AM503 user
Contents
1. n n Can t degauss the probe n Stray DC component in measurement C 2 Turn the instrument off wait a few seconds then power up the instrument Review installation and operating information in this manual If the error condition persists refer the instrument to qualified service personnel for repair Probe is not locked Probe is improperly connected to the AM 503A input connec tor Coupling is set to REF position Change to AC or DC Probe is not locked Probe is improperly connected to the AM 503A input connec tor Probe has been overloaded bumped or exposed to magnetic field Degauss the probe Appendix C Troubleshooting Guide Problem Measurements are inaccurate Measurements roll off at high frequen cies Measurements roll off at low frequen Remedy AM 503A output is not terminated into 50 O load Set input impedance of oscilloscope to 50 Q or connect a 50 Q feed through termination to the oscilloscope input not to the AM 503A output Vertical amplifier of oscilloscope is not at 10 mV div The oscilloscope ground reference is improperly adjusted The AM 503A DC LEVEL control is not adjusted to the zero current reference line The measurement exceeds the maximum continuous current or amp second product ratings of the probe see Section 3 Operation for more information about maximum current rat ings If possible upgrade to a probe with a higher current rating or use a CT2. Current 0A Figure 3 7 Applying the Amp Second Product Rule AM 503S User Manual 3 23 L Step 2 To determine the maximum allowable pulse amplitude mea sure the pulse width at the 5096 points see Figure 3 7 Divide the specified amp second or us product of your probe by the pulse width in seconds or us The quotient is the maximum allowable current The peak amplitude of the measured pulse must be less than this value For example if a pulse measured with an A6302 probe had a width of 3 us the maximum allowable peak current would be 100 A us divided by 3 US or 33 3 A NOTE Always degauss the probe after measuring a current that exceeds the maximum continuous current maximum pulsed current or amp second product rating of the probe Exceeding these ratings can magnetize the probe and cause measurement errors 3 24 Operation How to Extend the You may encounter situations where your measurement exceeds the maxi mum current rating of the connected probe This section discusses meth Measurement Range ods for extending AC and DC current ranges of the AM 503S To avoid personal injury or equipment damage do not exceed the specified electrical limits of the AM 503S or any applicable acces sories Extending the AC Range You can extend the AC amplitude limit of the AM 503S by using the Tek tronix CT 4 High Current Transformer The CT 4 designed for use with the A6302 current probe extends the A6302 range
3. Electron current flow is in the opposite direction of conventional flow flux the density of a magnetic field As the number of flux lines increases the magnetic field strength increases Current in the conductor under test generates flux lines in the probe core by inducing a voltage in the core Appendix B Glossary of Terms AM 503S User Manual Hall device a thin rectangular piece of semiconductor material located in the core of the current probe The Hall device uses the Hall effect for DC and low frequency AC measurements Hall effect the effect that produces a voltage potential in the Hall device when magnetic lines of force pass through the device The voltage potential is directly proportional to the the magnetic field strength The voltage polarity is determined by the magnetic field polarity A bias supply is required to produce the Hall effect The AM 503S current probes use the Hall effect for DC and low frequency AC measurements insertion impedance the equivalent series impedance introduced to a test circuit when the current probe is clamped around a test conductor magnetic susceptibility a figure expressing the amount of current induced into the probe by an external magnetic field of known intensity The lower the figure is the less the probe is influenced by external magnetic fields saturation a condition that occurs when the magnetic field strength in the probe core exceeds the maximum level that the core can
4. The amp second rating is equal to the peak current times the pulse width at the 5096 point auto balance a process that removes unwanted DC offsets from the AM 503A circuitry to ensure maximum measurement accuracy This process is performed during the probe degauss routine bucking current current fed back by the AM 503A to the current probe during DC and low frequency AC measurements Bucking current nulls most of the magnetic field in the probe core allowing linear DC and AC measurements simultaneously AM 503S User Manual B 1 conventional current flow the flow of the positive charge in a conductor Conventional current flow is from positive to negative The arrows on the A6302 and A6303 current probes point in the direction of conventional current flow Conventional current flow is in the opposite direction of electron flow degauss a process of eliminating residual magnetism from the probe core by feeding a decaying sine wave into the core The degaussing process should be performed before clamping the probe around a conductor whenever the probe becomes saturated by current overloads or when ever the probe is exposed to a magnetic field One of the units used to describe magnetic flux density is the Gauss electron current flow the flow of the electrons in a conductor Electron current flow is from negative to positive The arrows on the A6302 and A6303 current probes point in the opposite direction of electron current flow
5. 4 transformer Bandwidth limit is turned on Verify that bandwidth limit switches of both the AM 503A and the oscilloscope are set to the full bandwidth position The coupling is set to AC Verify that the coupling switches of cies AM 503S User Manual both the AM 503A and the oscilloscope are set to the DC position C 3 Problem Remedy Measurements exhibit excessive noise a Measurement aberrations exceed the specified limit Probe is not locked Probe is improperly connected to the AM 503A input AM 503A output is not terminated into 50 O load Set input impedance of oscilloscope to 50 Q or connect a 50 Q feed through termination to the oscilloscope input not to the AM 503A output AM 503A output is not terminated into 50 O load Set input impedance of oscilloscope to 50 Q or connect a 50 Q feed through termination to the oscilloscope input not to the AM 503A output The measurement exceeds the maximum continuous current or amp second product ratings of the probe for more informa tion see Section 3 Operation If possible upgrade to a probe with a higher current rating or use a CT 4 transformer Appendix C Troubleshooting Guide Problem Remedy Measurements exhibit excessive delay m AM 503A output is not terminated into 50 Q load Set input or slowed pulse response impedance of oscilloscope to 50 Q or connect a 50 Q feed through termination to the oscilloscope input not to the AM 503A o
6. 503A input You must have the probe slide locked in order to degauss the probe or to accurately measure current PROBE DEGAUSS AUTOBALANCE Button When pressed this button performs two functions that maximize measure ment accuracy First the AM 503A generates a degauss signal to remove any residual magnetism from the attached current probe Second the AM 503A initiates an operation to remove any undesired DC offsets from its Circuitry NOTE The probe degauss autobalance routine will not work if the current probe is unlocked or disconnected from the AM 503A input To properly degauss the current probe remove the probe from the conductor under test and lock the probe Control Summary To initiate the probe degauss autobalance function press the PROBE DEGAUSS AUTOBALANCE button momentarily The button will light while operating and go out after the operation is complete If REF coupling is selected when the PROBE DEGAUSS AUTOBALANCE button is pressed the DC level is reset to zero no offset after the routine If either AC or DC coupling is selected when the PROBE DEGAUSS AUTO BALANCE bution is pressed the DC level remains at its current setting NOTE The AM 503A front panel digital readout will display an error code 54 if the AM 503A is not properly terminated into 50 Q at the oscilloscope input Refer to Connecting the AM 503A to an Oscil loscope in Section 3 Operation for more information AM 503S User Manual 2
7. absorb When saturation occurs the probe no longer responds linearly to an increase in magnetic field strength resulting in measurement inaccuracies The probe core usually retains residual magnetism also producing inaccu racies A current overload condition will cause core saturation The probe should be degaussed after saturation occurs Appendix B Glossary of Terms Emily Appendix C Troubleshooting Guide HN Problem Front panel displays error code 54 This appendix lists possible problems that you may encounter when mea suring current with the AM 503S Use this appendix as a quick troubleshoot ing reference For a more in depth discussion of current measurement problems see Section 3 Operation Remedy m Probe is not terminated into 50 Q Set oscilloscope input im pedance to 50 Q setthe oscilloscope input coupling to DC m f oscilloscope input impedance is fixed at 1 MO attach 50 Q termination AM 503S standard accessory to oscilloscope input Do not attach termination to AM 503A output m Termination is attached to AM 503A output Remove and re attach termination to oscilloscope input Front panel display flashes LO during Battery is weak Battery replacement should be performed by power up AM 503S User Manual qualified service personnel Refer to the AM 503S Service Manual for more information Problem Remedy Front panel displays an error code 5 Can t make current measurement
8. and Terms 0 00 c cece eee eee eee ees 1 9 Specific Precautions 0 c cee eee 1 11 Operating Temperature 000ee cece e eens 1 13 Operating Voltage cece eee eee eens 1 13 Installing the AM 503A Into the Power Module 1 17 Packaging for Shipment 0000e sees eee eee eee 1 20 Customer Support 2 0 ccc cece eee eee eens 1 21 Service Support 0 0 eee 1 21 Sales Support ise cere cee eee es 1 21 Control Summary eei uela in a 2 1 DC LEVEL Control Ta OE 0 0 ccc cece E een a 2 3 OVERLOAD Indicator 0 0 c cece eee eee 2 5 PROBE OPEN Indicator 00 00 cece eee eees 2 6 PROBE DEGAUSS AUTOBALANCE Button 2 6 CURRENT DIVISION Control 2 222222 seen 2 8 COUPLING Buttons 0 0 ccc cece ene eens 2 8 BW LIMIT Button 00 0c cece eens 2 9 OUTPUT Connector 0 ccc cece eens 2 10 INPUT Connector 0 0 cc cece eee eens 2 10 Release Lever 02 eee ee ee eh ne 2 11 Contents Operation ee eed urere eara eda ede ae 3 1 Choosing an Oscilloscope to Use with the AM 5038S 3 1 Connecting the AM 503A to an Oscilloscope 3 2 Adjusting the Oscilloscope seeeeeeeese 3 4 Using the Current Probes eeeeeeeee 3 5 Choosing a Probe 0 cece eee 3 5 Connecting a Current Probe to the System 3 6 Operating the Pr
9. buck ing current to the displayed measurement Operation Under no circumstances should you exceed the maximum continu ous or pulsed current limits of the probe or the conductors If the probe limits are exceeded remove the conductors from the probe and perform the probe degauss autobalance routine NOTE Adding a second conductor to the probe increases the insertion inductance and reduces the upper bandwidth limit of the probe Winding multiple turns further increases the insertion inductance further reducing the upper bandwidth limit AM 503S User Manual 3 27 N Current pu garen RN Conductor Under Test Conductor Under Test Extra Turns Added Bucking Current to Increase A6302 Supplied by A6302 Bucking Current Current Second Conductor Current Probe Probe a Adding a Second Conductor b Adding Multiple Turns Figure 3 8 Increasing the DC Measurement Range 3 28 Operation How to Increase the If you are measuring DC or low frequency AC signals of very small ampli MI tudes you can increase measurement sensitivity by winding several turns of Sensitivity of the the conductor under test around the probe as shown in Figure 3 9 The AM 503S signal is multiplied by the number of turns around the probe When viewing the signal on the oscilloscope screen divide the displayed amplitude by the number of turns to obtain the actual current value For example if a conduc tor is wrapped around the probe five time
10. of Multiple Conductor Cable 4 15 Appendix A Specifications seeeuueeeeeeeeeee A 1 Appendix B Glossary of Terms 000ceeeeee eee eens B 1 Appendix C Troubleshooting Guide C 1 Index a a Re en ie l 1 Change Information Contents Bi WU LLL List of Figures AM 503S User Manual Figure 1 1 Components of the AM 5038 Figure 1 2 TM 502A Voltage Selector Figure 1 8 Changing the TM 502A Operating Voltage Figure 1 4 Installing the AM 503A Into the Power Mo Figure 2 1 The AM 503A Front Panel dule Figure 3 1 Connecting the AM 503A to an Oscilloscope Figure 3 2 Connecting a Current Probe to the AM 503A Figure 3 3 Operating the A6302 Current Probe Slide Figure 3 4 Operating the A6303 Current Probe Slide Figure 3 5 Measuring Current with the AM 5038 Figure 3 6 Effect of Probe Coupling on Low Frequency Measurements 0 0 cee eee eee ees Figure 3 7 Applying the Amp Second Product Rule Figure 3 8 Increasing the DC Measurement Range Figure 3 9 Increasing Probe Sensitivity Figure 3 10 Measuring Differential Current and Nulls 1 4 1 14 1 16 1 19 2 2 3 3 3 7 3 10 3 11 3 16 3 19 3 23 3 28 3 30 3 32 ix Figure 4 1 Setup for Measuring Charging Current 4 3 Figure 4 2 Charge Current Waveforms sssssssss
11. shown in Figure 1 1 AM 503A Current Probe Amplifier A6302 Current Probe for optional probes see the options list TM 502A Power Module Toolbox AC Power cord BNC Output cable 50 Q Termination User Manual and Quick Reference card In addition to the AM 503S system you need an oscilloscope to display the AM 503S measurements The oscilloscope bandwidth should be approxi mately four times the bandwidth of your current probe and should be capa ble of displaying a vertical scale factor of 10 mV div 1 3 Output Cable User Manual Quick Reference Termination Toolbox TM 502A A6302 Probe A6303 Probe Optional Figure 1 1 Components of the AM 503S 1 4 General Information AM 503S User Manual AM 503A Current Probe Amplifier The AM 503A is a single width instrument that plugs into any Tektronix TM 500 or TM 5000 series power module The AM 503A amplifies the current sensed by the probe and converts the current to a proportional voltage that is displayed on an oscilloscope or other similar measuring device Current Probes The probes available for use with the AM 503S system are the A6302 and the A6303 These probes cover a wide range of applications for information about maximum operating limits see Appendix A Specifications A stan dard AM 503S system includes the A6302 Probe you may add or substitute the A6303 Probe see the Options list in this section for alternative syste
12. simultaneously measure AC and DC current The AM 503A amplifier converts the sensed current into a proportional voltage signal that you can measure directly with an oscillo scope or similar measuring device You can select the probe that best matches your application Each probe uses a moveable slide to clamp around the conductor under test Section 3 Operation and Section 4 Applications provide information to help you choose the correct probe for your application The AM 5088 provides better linearity than other current measurement Systems because of a current feedback process used with the probe DC measurement capability and high bandwidth allow the AM 5038 to accu rately represent square waves and fast rise signals The high sensitivity of the AM 503A maximizes measurement precision 1 1 Features Applications 1 2 The AM 503A Current Probe Amplifier includes these features m simultaneous DC and AC current measurements m high sensitivity m one button autobalancing and probe degaussing The AM 5088 Current Probe System can be used in a wide variety of DC and AC measurement applications m motor start up circuits m power supplies and inverters m automotive signals m inductance measurements Some typical applications of the AM 503S are presented in Section 4 Applications General Information AM 503S System Components AM 503S User Manual The standard AM 503S Current Probe System includes the following items
13. 1T ip Ua TUT Appendix A Specifications 1111 Appendix A lists some specifications of the AM 503S Current Probe System the system includes an AM 503A amplifier a current probe and a TM 502A power module These specifications are valid only under the following conditions m the system has been calibrated at an ambient temperature between 20 C and 30 C m the system is operating in an environment whose limits are described in Table A 3 the operating temperature limits are 0 C to 50 C unless otherwise stated m the system has had a warm up period of at least 20 minutes m the probe degauss autobalance routine has been performed after the 20 minute warm up period m the AM 503A is properly terminated into 50 Q AM 503S User Manual A 1 Because of a connector change these specifications apply only to probes above certain serial numbers Refer to the AM 503S Service Manual for more information Specifications are subject to change without notice Specifications are separated into two categories warranted specifications and nominal or typical characteristics Warranted characteristics Table A 1 are guaranteed performance specifica tions See the AM 503S Service Manual for the performance verification procedures Nominal and typical characteristics Table A 2 are not guaranteed and are provided to characterize the configuration performance or operation of typical systems Table A 1 Warranted AM 503S Characte
14. 2 A6303 669 g 1 475 Ib AM 503S User Manual A 7 A 8 Maximum Input Current Amperes P P A6303 200 Derating Curves Maximum Input Current 100 50 A6202 10 1 1 kHz 10 kHz 100 kHz 1 MHz 10 MHz 50 MHz Frequency Figure A 1 Frequency Derating Curves Appendix A Specifications Amperes Peak AM 503S User Manual 50 40 30 20 10 Max Peak Pulse A6302 System Amp Second Product Limits en Any Width 1 2 3 4 5 Allowable Pulse Width Microseconds Figure A 2 A6302 Amp Second Product Curve A 9 Max Peak Pulse 500 400 A6303 System Amp Second Product Limits 300 7 Amperes Peak 200 7 100 m Any Width 10 20 30 40 50 60 70 80 90 100 Allowable Pulse Width Microseconds Figure A 3 A6303 Amp Second Product Curve A 10 Appendix A Specifications 1 0 4 ne Typical Impedance T Impedance Deviation AT A A 7 A 02 7 7 o e ee 7 g x A S 0 1 r
15. 2 input of your oscilloscope Pull the release lever to remove the AM 503A from the power module e A l OSCILLOSCOPE AT 10mV DIVISION 20MHz BW LIMIT COUPLING AC REF DC INPUT e the attached current probe is unlocked The PROBE DEGAUSS AUTOBALANCE button removes magnetism from the attached current probe The probe must be removed from the test circuit and locked The CURRENT DIVISION knob changes the AM 503A scale factor The COUPLING switches select AC or DC probe coupling or a zero current reference The current probes connect to the AM 503A at the INPUT connector Figure 2 1 The AM 503A Front Panel 2 2 Control Summary DC LEVEL DC LEVEL Control The DC LEVEL control adjusts the DC offset that appears at the AM 503A output connector The DC LEVEL control has the same effect on the dis played waveform as the vertical position control of the oscilloscope After setting a zero current reference the oscilloscope vertical position control is not used Turn the DC LEVEL control clockwise to move the displayed waveform up the oscilloscope screen Turn it counterclockwise to move the waveform down the screen The adjustment sensitivity changes from fine to coarse if the waveform is moved more than approximately one major division during an adjustment Reversing direction restores the fine adjustm
16. 7 CURRENT DIVISION EE OSCILLOSCOPE AT 10mV DIVIS e ION 2 8 COUPLING REF IE 3 CURRENT DIVISION Control The CURRENT DIVISION control sets the scale factor sensitivity of the AM 503A in a 1 2 5 sequence The setting of this control is displayed on the digital readout and the units indicator Rotate the knob clockwise to de crease the scale factor increase the instrument sensitivity and counter clockwise to increase the scale factor decrease the instrument sensitivity The CURRENT DIVISION display indicates the AM 503A scale factor only The measurement output is displayed on the oscilloscope NOTE To maintain accurate measurements the vertical gain of the oscillo scope must remain at 10 mV div COUPLING Buttons The COUPLING buttons determine the coupling between the current probe and the AM 503A To couple the current probe for DC plus AC measure ments press the DC button To couple the current probe for AC measure Control Summary ments only press the AC button To establish a zero current reference press the REF button and adjust the DC LEVEL control described earlier When pressed a coupling button lights to indicate the selected mode NOTE To maintain correct operation of the AM 503A coupling buttons leave the input coupling of your oscilloscope at DC 20 MHz BW LIMIT Button BW LIMIT oe Pressing the BW LIMIT bandwidth limit button alt
17. 800 426 2200 AM 503S User Manual 1 21 1 22 General Information Igi ip u gig VU U U L Control Summary This section describes the function of each AM 503A front panel control and connector The overview in Figure 2 1 is followed by a more detailed de scription of each item For more information about using these controls in measurement applications see Section 3 Operation and Section 4 Ap plications The AM 503A has two modes of operation normal and test mode This section describes the normal mode function of each control and connector The test mode function is described in Section 3 Operation AM 503S User Manual 2 1 The DC LEVEL knob vertically positions the signal on the oscilloscope screen Rotate the knob to move the signal up or down the screen The OVERLOAD indicator lights when a AM 503A CURRENT PROBE AMPLIFIER DC LEVEL measurement exceeds the maximum continuous current ratings of the AM 503S system The CURRENT DIVISION display shows ERI The PROBE OPEN indicator lights when PROBE OPEN OVER LOAD DEGAUSS AUTOBALANCE REMOVE PROBE FROM CIRCUIT AND CLOSE CURRENT DIVISION r mA DIV ADV the current AM 503A scale factor in either mA division or A division The 20 MHz BW LIMIT button alternately selects or deselects a 20 MHz bandwidth limit for noise filtering The AM 503A output appears at the OUTPUT connector Connect this output to a 50
18. A from the power module To avoid equipment damage turn the power module off before removing or installing any plug in unit Control Summary Bi WU rr Operation This section describes how to operate the AM 503S and discusses factors you should consider when measuring current with the AM 503S system Appendix C Troubleshooting Guide provides a list of common measure ment problems and their solutions Choosing an Sr i Lar E to de us Er ea be o utilize the full bandwidth capability of the and attached curren eee probe the oscilloscope bandwidth should be approximately four times that WI of the current probe For example when using an A6302 probe the oscillo scope bandwidth should be at least 200 MHz When using an A6303 probe the oscilloscope bandwidth should be at least 60 MHz The oscilloscope must also be capable of displaying a vertical scale factor of 10 mV div AM 503S User Manual 3 1 Connecting the AM 503A to an Oscilloscope 3 2 To connect the AM 503A output connector to your oscilloscope use a 50 O BNC cable one is supplied with your AM 503S system Connect one end of the cable to the AM 503A output connector and the other end to the input of the desired vertical channel of your oscilloscope see Figure 3 1 The input impedance of the oscilloscope channel must be 50 Q otherwise you will encounter slowed pulse response increased aberrations or incorrect DC measurement amplitudes NOTE If your oscill
19. LEVEL control of the AM 503A Now you can view large DC component signals without the signal degrada tion that can occur when low frequency signals are AC coupled Operation a AC Coupled signal b DC Coupled signal Figure 3 6 Effect of Probe Coupling on Low Frequency Measurements AM 503S User Manual Probe Bandwidth If you want to observe a low frequency signal either DC or AC below 20 MHz that has high frequency noise activate the AM 503A bandwidth Considerations limit The noise level will be reduced To avoid personal injury or equipment damage do not exceed the specified bandwidth limits of your current probe Measuring fre quencies in excess of the specified limit can cause the probe to overheat severely 3 20 Operation Maximum Current Limits of the Probes AM 503S User Manual The current probes have three maximum current ratings continuous pulsed and amp second product Exceeding any of these ratings can saturate the probe core magnetizing the core and causing measurement errors Appendix A Specifications lists the maximum current ratings for each probe Maximum Continuous Current This rating refers to the maximum current that can be continuously mea sured at DC or at a specified AC frequency The maximum continuous current value is derated with frequency as the frequency increases the maximum continuous current rating decreases Maximum Pulsed Current This rating defines the maximum peak va
20. Step 2 Disassemble the voltage selector as shown in Figure 1 3 Step 3 Rotate the selector until the proper voltage appears in the window L Step 4 Reassemble the voltage selector and push it back into the power module until it snaps into place Step 5 Using the correct power cord connect the power module to the AC line receptacle AM 503S User Manual 1 15 Rotate fuse block so that the correct voltage appears in the window Fuse Fuse Block Selector Window Figure 1 3 Changing the TM 502A Operating Voltage 1 16 General Information Installing the AM 503A Into the Power Module AM 503S User Manual After you have connected the power module to the correct line source and have verified that the power switch is off you may install the AM 503A amplifier into the power module Make sure the power switch of the power module is off before installing the AM 503A and before connecting a current probe to the AM 503A If you install or remove a plug in instrument while the power module is on you might damage the equipment Align the grooves of the AM 503A with the rails of the power module and push the AM 503A into the power module until the instrument snaps into place see Figure 1 4 To remove the AM 503A grasp the release lever and pull the instrument out of the power module After you have installed the AM 503A and any other desired plug in instru ments into the power module you may turn the power module
21. Tektronix service center is located Customer shall be responsible for paying all shipping charges duties taxes and any other charges for products returned to any other locations This warranty shall not apply to any defect failure or damage caused by improper use or improper or inadequate maintenance and care Tektronix shall not be obligated to furnish service under this warranty a to repair damage resulting from attempts by personnel other than Tektronix representatives to install repair or service the product b to repair damage resulting from improper use or connection to incompatible equipment or c to service a product that has been modified or integrated with other products when the effect of such modification or integration increases the time or difficulty of servicing the product THIS WARRANTY IS GIVEN BY TEKTRONIX WITH RESPECT TO THIS PRODUCT IN LIEU OF ANY OTHER WARRANTIES EXPRESSED OR IMPLIED TEKTRONIX AND ITS VENDORS DISCLAIM ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE TEKTRONIX RESPONSIBILITY TO REPAIR OR REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND EXCLUSIVE REMEDY PROVIDED TO THE CUSTOMER FOR BREACH OF THIS WARRANTY TEKTRONIX AND ITS VENDORS WILL NOT BE LIABLE FOR ANY INDIRECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER TEKTRONIX OR THE VENDOR HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES Kain WU WLLL Welcome Conventions AM 503S User Manual This ma
22. User Manual Tektronix 7 AM503S Current Probe System 070 8170 00 Please check for change information at the rear of this manual First Printing March 1992 Copyright Tektronix Inc 1992 All rights reserved Tektronix products are covered by U S and foreign patents issued and pending Information in this publication supercedes that in all previously published material Specifications and price change privileges reserved Printed in the U S A Tektronix Inc P O Box 1000 Wilsonville OR 97070 1000 TEKTRONIX and TEK are registered trademarks of Tektronix Inc WARRANTY Tektronix warrants that this product will be free from defects in materials and workmanship for a period of one 1 year from the date of shipment If any such product proves defective during this warranty period Tektronix at its option either will repair the defective product without charge for parts and labor or will provide a replacement in exchange for the defective product In order to obtain service under this warranty Customer must notify Tektronix of the defect before the expiration of the warranty period and make suitable arrangements for the performance of service Customer shall be responsible for packaging and shipping the defective product to the service center designated by Tektronix with shipping charges prepaid Tektronix shall pay for the return of the product to Customer if the shipment is to a location within the country in which the
23. aging the AM 503A do not connect or disconnect a current probe while the probe is clamped around a live conductor or while the AM 503A is turned on Excessive voltages and surge currents can result To connect a current probe to the AM 503A input connector align the tab of the probe connector with the slot in the AM 503A input connector see Figure 3 2a Align the dot on the probe connector with the groove opening of the input connector as shown in Figure 3 2b Push the probe connector in while twisting the barrel clockwise to lock the connector Operation AM 503A Push connector in and twist to lock A SE Probe Connector S a AM 503A Alignment Slot Groove Dot a Aligning the Tab with the Connector Slot b Inserting the Connector into the AM 503A Figure 3 2 Connecting a Current Probe to the AM 503A AM 503S User Manual 3 7 3 8 Each current probe is calibrated before it is shipped and should not require further adjustment If a probe requires calibration refer to the AM 503S Service Manual for calibration instructions or contact your Tektronix service representative Operating the Probe Slide The A6302 and A6303 current probes each have a slide mechanism that opens and closes the probe jaw allowing you to clamp the probe around a test conductor The slide must be locked to accurately measure current or to degauss the probe If a probe is
24. aking AC current measurements leave the oscillo scope coupling on DC You need only change the AM 503A cou pling to AC If you need to measure high amplitude AC currents consider using a CT 4 High Current Transformer with an A6302 probe The CT 4 provides step down ratios of 20 1 or 1000 1 For more information about the CT 4 consult your Tektronix sales representative AM 503S User Manual Probe Coupling Considerations 3 18 You can couple the current probe to the AM 503A with either DC or AC coupling DC coupling shows the DC and AC measurement components while AC coupling quickly and conveniently removes the DC component AC coupling can present some problems at frequencies below 7 Hz For example pulsed currents may exhibit rolloff or decreased amplitude Fig ure 3 6a shows a low frequency square wave observed using AC coupling The signal exhibits low frequency rolloff By changing the AM 503A coupling to DC the pulse flattens out as shown in Figure 3 6b If you are trying to examine a low frequency signal that is superimposed on a comparatively large DC component you can resolve the signal by per forming these steps C Step 1 Set the AM 503A coupling to AC C Step 2 Adjust the CURRENT DIVISION control of the AM 503A so that the signal shows maximum detail without going off the oscilloscope screen C Step 3 Set the AM 503A coupling to DC Center the DC component on the zero current line by adjusting the DC
25. as started and the lights were turned on to add a significant load to the circuit Applications Battery To Ground Alternator To Ground Figure 4 1 Setup for Measuring Charging Current AM 503S User Manual 4 3 4 4 After adjusting the equipment to the following settings the waveform repre sented in Figure 4 2a was obtained AM 503A COUPLING DC DC LEVEL eee 0 V zero current reference is set at oscilloscope ground reference line CURRENT DIVISION 10A BW LIMIT off Oscilloscope Coupling DC Volts Division 10 mV Zero Current Reference center graticule line Timebase 200 us division Applications The waveform in Figure 4 2a shows the three phase ripple frequency The average charge current is about 27 A with a minimum peak of about 23 A and a maximum peak of about 31 A The waveform shows a continuous cycle with no dropouts so the alternator circuit appears to be functioning properly A single phase diode failure would normally appear as an extreme drop in charge current every third cycle as shown in Figure 4 2b a Normal Waveform b Waveform with One Bad Phase Figure 4 2 Charge Current Waveforms AM 503S User Manual 4 5 Inductance Measur
26. at the desired zero current reference C Step 3 Set the input coupling of the oscilloscope to DC L Step 4 Turn off any oscilloscope bandwidth filters L Step 5 Make sure the oscilloscope input is terminated with a 50 Q impedance Operation Using the Current Probes AM 503S User Manual NOTE Do not change the vertical amplifier settings of the oscilloscope while using the AM 5038S All subsequent measurement adjust ments should be made on the AM 503A amplifier To maintain accurate readings the vertical gain of the oscilloscope channel must remain at 10 mV DIV and the coupling must remain at DC This section describes how to select a current probe for your application and how to operate the current probes available with the AM 503S Choosing a Probe Before choosing a current probe carefully consider your application If you need to measure low amplitude or high frequency currents try using an A6302 probe If you need to measure higher current values at lower fre quencies consider using the A6303 probe or a CT 4 High Current Trans 3 5 3 6 former with an A6302 probe Consult the specification tables in Appendix A Specifications to determine which probe will work best with your specific application and read Section 4 Applications Connecting a Current Probe to the System Handle the current probes with care To avoid damaging the probe core do not drop the probe or subject it to impact Also to avoid dam
27. by a factor of 20 1 or 1000 1 and can provide external DC bucking current up to 300 A For more in formation about the CT 4 consult your Tektronix sales representative Because the CT 4 has a lower AC bandwidth limit than the A6302 probe set the AM 503A coupling to DC when using the CT 4 AM 503S User Manual 3 25 3 26 Extending the DC Range If you want to measure a low amplitude AC component that is superim posed on an extremely large steady state DC component such as ina power supply or if you want to extend the DC current range of your probe you can add offset bucking current with a second conductor To supply additional bucking current place a second conductor that has a pure DC component of known value in the probe jaw with the conductor under test see Figure 3 8a Orient the second conductor so that the buck ing current flows in the opposite direction of the DC flow in the conductor under test You can increase the value of the bucking current by winding multiple turns of the second conductor around the probe as shown in Figure 3 8b The bucking current is equal to the current flowing in the conductor times the number of turns wound around the probe For example if the second conductor has a current of 100 mA DC flowing through it and it is wrapped around the probe five times the additional DC bucking current is 100 mA multiplied by 5 or 500 mA DC To determine measurement values simply add the value of the extra
28. d Ld 3 Z z ZH c 05 a 7 9 7 Z 2 Z S Ral 02 01 0 1 0 2 0 5 1 2 5 10 20 50 Frequency MHz Figure A 4 A6302 Insertion Impedance Curve AM 503S User Manual A 11 1 0 05 Typical Impedance Impedance Deviation 02 X Q o 0 1 3 Q c 05 2 o o S 02 01 0 1 0 2 0 5 1 2 5 10 20 50 Frequency MHz Figure A 5 A6303 Insertion Impedance Curve A 12 Appendix A Specifications Maximum Wire Size 3 8 mm 0 15 in A6302 Jaw Dimensions Figure A 6 AM 503S User Manual 40 6 mm 21mm 1 6 in gt lt 0 83 in LL 67 3 mm n 25 4 2 65 in 1 0 in N y Y L Maximum Wire Size 21 1 mm 0 83 in A6303 Jaw Dimensions Probe Jaw Dimensions A 13 Appendix A Specifications 1T ip INS Appendix B Glossary of Terms ML This appendix defines some technical terms used in this manual amp second product the unit of measure defining the maximum amount of pulsed current that can be measured before the probe core becomes saturated The amp second rating applies only to measurement values between the maximum continuous and maximum pulse current ratings of the probe
29. d the input impedance is set to 50 Q C Step 2 Adjust the ground reference of the oscilloscope so the zero current trace appears at the desired graticule line L Step 3 Lock the probe press the AM 503A REF coupling button and then press the AM 503A PROBE DEGAUSS AUTOBALANCE button C Step 4 After the degauss autobalance routine completes reposition the ground reference if necessary on your oscilloscope using the AM 503A DC LEVEL control C Step 5 Open the probe slide place the probe around the conductor under test and then lock the slide NOTE For correct measurement polarity make sure the probe arrow is pointing in the direction of conventional current flow conventional current flow is from positive to negative L Step 6 Press the AM 503A DC coupling button and set CURRENT DI VISION to the desired scale Operation AM 503S User Manual L Step 7 To vertically position the resulting waveform use the DC LEVEL control of the AM 503A C Step 8 Adjust the oscilloscope time base as needed Figure 3 5 shows a current probe connected to a power supply line Notice that the probe arrow points toward the negative terminal of the power supply 3 16 A6302 Current Probe Figure 3 5 Measuring Current with the AM 503S Operation AC Measurements To measure AC current only follow the same basic instructions for DC current measurements except change the AM 503A coupling to AC NOTE Even when m
30. e should be oper ated by qualified service personnel only Test mode is entered by performing these steps L Step 1 Press and hold the BW LIMIT button Operation L Step 2 Momentarily press the PROBE DEGAUSS AUTOBALANCE button Step 3 Release the BW LIMIT button The AM 503A readout will dis play a routine number To exit the test mode perform these steps C Step 1 Press the BW LIMIT button so that the button is dark L Step 2 Rotate the DC LEVEL knob or press one of the COUPLING buttons The instrument should return to normal operation AM 503S User Manual 3 35 Maintenance The AM 5038 requires little maintenance during normal use The primary maintenance involves cleaning accumulated dirt from the probe body and if necessary cleaning the exposed core surfaces in the probe jaw To clean the probe body use a soft cloth dampened in a solution of mild detergent and water To clean the core open the jaw and clean the exposed core surfaces with the cloth Avoid using chemical cleaning agents that damage plastic For example avoid using chemicals that contain benzene toluene xylene acetone or similar solvents Recommended cleaning agents are isopropyl alcohol Isopropanol or ethyl alcohol Foto col or Ethanol For additional maintenance and repair information refer to the AM 503S Service Manual available as an optional accessory or send the component to your nearest Tektronix service center 3 36 Op
31. eed the amp second product Maximum Voltage 500 V 700 V bare wire Power Consumption 17 Watts maximum 17 Watts maximum Random Noise 4 MVRMS 4 MVRMS A 4 Appendix A Specifications Table A 3 AM 503S Environmental Characteristics Name Description Ambient Temperature Operating 0 C to 50 C Non Operating 55 C to 75 C Humidity Operating 50 C to 9596 R H Non Operating 60 C to 9596 R H Altitude Operating 4 570 m 15 000 ft maximum Non Operating 15 200 m 50 000 ft maximum AM 503S User Manual A 5 Table A 4 AM 503S Physical Characteristics Name Description A6302 Probe Body Length 200 mm 7 875 in Width 15 9 mm 0 625 in Height 31 8 mm 1 25 in Jaw Opening see Figure A 6 3 81 mm 0 15 in Cable Length 2 m 6 56 ft Maximum Conductor Diameter see Figure A 6 A6303 Probe Body Length Width Height Jaw Opening see Figure A 6 Cable Length Maximum Conductor Diameter see Figure A 6 A 6 3 81 mm 0 15 in or 8 ga AWG solid bare wire 268 mm 10 55 in 40 6 mm 1 60 in 156 mm 6 13 in 21 1 mm 0 83 in x 25 4 mm 1 0 in 2 m 6 56 ft 21 1 mm 0 83 in or 500 ga AWG stranded bare wire Appendix A Specifications Table A 4 AM 503S Physical Characteristics Name Description TM 502A AM 503A excluding knobs Length 40 7 cm 16 6 in Width 14 5 cm 5 7 in Height 14 0 cm 5 5 in Net Weight TM 502A 4 0 kg 8 75 Ib AM 503A 0 91 kg 2 Ib A6302 250 g 8 8 0
32. ements You can use the AM 5038 to measure inductance of coils Two different methods can be used One method applies to low impedance pulse sources and the other method applies to higher impedance pulse sources of known value Low Impedance Pulse Sources Figure 4 3 shows a measurement setup using a constant voltage pulse generator of extremely low output impedance The inductor is connected across the output terminals of the pulse source The current probe is at tached to one of the source leads and the current ramp is measured The inductance is effectively defined by the slope of the current ramp shown in Figure 4 4 and is mathematically expressed by the following formula pat omar where L is the inductance in henries E is the voltage of the pulse generator dt is the change in time and di is the change in current Applications Flow i Pulse Generator Inductor Current A6302 Current Probe en Figure 4 3 Measuring Inductance with a Low Impedance Source AM 503S User Manual Current Flow i Y Time t Figure 4 4 Linear Current vs Time Ramp 4 8 Applications Higher Impedance Pulse Sources If the pulse source has a higher impedance of known resistance such that the output voltage drops as the current increases the inductance of a coil can be calculated by the time constant of the charge curve Figure 4 5 shows the setup diagram wh
33. ent mode If REF coupling is selected when the PROBE DEGAUSS AUTOBALANCE button is pressed the DC level is reset to zero no offset after the routine If either AC or DC coupling is selected when the PROBE DEGAUSS AUTO BALANCE bution is pressed the DC level remains at its current setting AM 503S User Manual 2 3 NOTE To maintain measurement accuracy position the signal with the AM 503A DC LEVEL control Do not adjust the vertical position control of your oscilloscope once you have established a zero cur rent reference Control Summary OVERLOAD Indicator LOAD When lighted this indicator informs you that the measurement you are taking exceeds the continuous amplitude limit of the AM 5038 To correct an overload situation use an A6303 probe or use a CT 4 High Current Trans former with the A6302 Probe If the overload problem persists then the current is too high to accurately measure with the AM 503S system Since overloads can magnetize the probe you should always degauss the probe after an overload condition occurs To avoid personal injury or equipment damage do not exceed the specified electrical limits of the AM 503S or any applicable acces sories AM 503S User Manual 2 5 2 6 PROBE OPEN PROBE DEGAUSS AUTOBALANCE REMOVE PROBE FROM CIRCUIT AND CLOSE PROBE OPEN Indicator When lighted this indicator informs you that the current probe is unlocked or that no probe is connected to the AM
34. eration To avoid injury or equipment damage refer servicing to qualified service personnel only AM 503S User Manual 3 37 3 38 Operation EREW UU rrr Applications This section describes the following typical measurement applications of the AM 5038 Current Probe System AM 503S User Manual automobile charging systems inductance measurements inductor turns measurements continuity checks 4 1 Automobile Charging Systems This application examines the charging current from an automobile alterna tor circuit Most automotive charging systems are three phase alternators with a corresponding diode network Observing the charge current wave form can quickly reveal if a diode circuit is shorted or open A simple current meter will not detect a single phase diode problem because the meter averages the total charge current The AM 503S current measurement system can detect a diode failure by instantaneously monitoring any abnor mal fluctuation in charge current The diagram in Figure 4 1 shows the equipment setup Since the currents associated with charging systems are somewhat high and the frequencies are fairly low an A6303 Current Probe was used for this application The A6303 was degaussed and then clamped around the positive battery lead from the alternator Because the probe is referenced to conventional current flow the probe arrow points away from the alternator and toward the battery side of the circuit The automobile w
35. ernately selects the full EXE bandwidth capability of the current probe AM 503A combination or a limited 20 MHz bandwidth Use the bandwidth limit function when you are measur ing DC or low frequency currents and you want to filter high frequency noise When the BW LIMIT button lights the bandwidth limit is on and when the button is unlighted the bandwidth limit is off AM 503S User Manual 2 9 2 10 INPUT N A OUTPUT Connector The AM 503A measurement output appears at the OUTPUT connector Attach one end of a 50 Q BNC cable to this connector and the other end to a 50 Q vertical input of your oscilloscope The output impedance of the AM 503A is 50 Q NOTE To obtain accurate measurements the input impedance of your oscilloscope must be 50 Q With 1 MOQ oscilloscopes use a 50 Q feedthrough termination one is supplied with the AM 503S sys tem Connect the termination to the oscilloscope input not the AM 503A output Failure to properly terminate the AM 503A will result in an error code 54 being displayed on the AM 503A front panel digital readout INPUT Connector The current probes attach to the AM 503A at the INPUT connector a 12 pin female connector For information about attaching a probe to this connector see Section 3 Operation Control Summary AM 503S User Manual Release Lever The release lever has the Tektronix name printed on it Pull the release lever to remove the AM 503
36. esigned to operate from a power source that will not apply more than 250 Vams between the supply conduc tors or between either supply conductor and ground A protective ground connection by way of the grounding conductor in the power cord is essen tial for safe operation Grounding the Product This product is grounded through the ground ing conductor of the power cord To avoid electrical shock plug the power cord into a properly wired receptacle before connecting equipment to the product input or output terminals The protective ground conductor in the power cord is essential for safe operation Danger Arising from Loss of Ground Upon loss of the protective ground connection all accessible conductive parts including knobs and controls that may appear to be insulating can render an electrical shock Use the Proper Power Cord Use only the power cord and connector specified for your product and use only a power cord that is in good condi tion Any changes to the cord or power connector should be performed by qualified service personnel only Use the Proper Fuse To avoid fire hazard use only the fuse of correct type voltage rating and current rating as specified in the parts list for your product Fuse replacement should be performed by qualified service per sonnel only Do Not Operate in Explosive Atmospheres To avoid explosion do not operate this product in an explosive atmosphere unless it has been specificall
37. he pre viously described one except the reference coil and the test coil are in serted into the current probe so that the currents oppose each other see Figure 4 8 You must observe the polarity of coil current to determine whether the test coil has more or fewer turns than the reference coil The turns are calculated by using the formula N N Im I where N3 is the number of turns in the test coil N is the number of turns in the reference coil I is the measured coil current and is the input cur rent Applications Measure Input Current Here gt Current Flow i ur Figure 4 7 Measuring the Number of Turns in a Coil AM 503S User Manual Clamp probe around coil to measure current from coil turns 4 13 A6303 Current Probe Electron Flow in Coil 1 Y ee N Input Current a Now EL Electron Flow in Coil 2 Figure 4 8 Turns Measurement Using Reference Coil 4 14 Applications Continuity Test of Multiple Conductor Cable AM 503S User Manual Individual conductors of a multiple conductor cable can be tested with the AM 5038 To check a conductor clamp the current probe around the entire cable and check for a specific known current signal If there is no current or the current is abnormally low then the conductor has a continuity problem If the current is abnormally high then the conductor may have a short to ground Applications
38. ich is similar to the previous example The current ramp represented in Figure 4 6 shows how the values for the induc tance formula are obtained Use this formula to calculate the inductance based on the current measure ment L tR where L is the inductance in henries t is the time required for the current to rise or fall 63 2 of the total current value and R is the source resistance of the pulse generator AM 503S User Manual 4 9 Resistance Flow i Current Pulse Generator B Inductance A6302 Current Probe an Figure 4 5 Measuring Inductance with a High Impedance Source Applications Current Flow i 100 63 2 36 8 0 Time t Figure 4 6 High Impedance Source Current Ramp AM 503S User Manual 4 11 Measuring Inductor Turns Count To obtain an approximate turns count of an inductor connect the inductor to a current limited source as shown in Figure 4 7 Measure the input current on one of the inductor leads then clamp the current probe around the inductor and note the current value The number of turns is equal to the ratio of coil current to input current The accuracy of this method is limited by the current measurement accuracy The following method allows more precise turns measurement For a more precise turns count you need a coil with a known number of turns to use as a reference The measurement setup is similar to t
39. l controls 2 7 G Gauss B 2 glossary of terms B 7 l 2 increasing bucking current 3 26 increasing probe sensitivity 3 29 inductance measurements 4 6 INPUT connector 2 10 insertion impedance B 3 installing the AM 503A 1 17 L locking the probes 3 8 low battery indication 3 33 M maintenance 3 36 maximum continuous current rating 3 21 maximum pulsed current rating 3 21 measuring continuity 4 15 measuring current AC 3 17 current nulls 3 31 DC 3 13 differential current 3 31 measuring inductance 4 6 O optional accessories 1 8 optional power cords 1 8 options 1 7 OUTPUT connector 2 10 OVERLOAD indicator 2 5 Index P parts i power cords 1 8 PROBE DEGAUSS AUTOBALANCE button 2 6 3 12 PROBE OPEN indicator 2 6 probes bandwidth considerations 3 20 coupling 3 18 degaussing demagnetizing 2 6 3 12 description 1 5 increasing the current limit 3 25 maintenance 3 36 maximum current limits 3 27 operation 3 8 saturation 3 27 selecting 3 5 AM 503S User Manual R rear interface output 3 2 release lever 2 77 replaceable parts S Safety Symbols 1 10 safety information 1 9 saturation B 3 specifications A 1 susceptibility B 3 T termination resistor 1 6 3 2 test mode 3 34 toolbox 1 7 troubleshooting C 1 V voltage selector 1 13 W WARNING statement in manual 1 9 Index
40. lue of pulsed current the probe can accurately measure regardless of how short within bandwidth limita tions the pulse duration is 3 21 3 22 Amp Second Product The amp second product defines the maximum width of pulsed current that you can measure when the pulse amplitude is between the maximum continuous and maximum pulsed current specifications don t forget to derate the maximum continuous specification according to the pulse fre quency If a measurement exceeds the specified amp second product probe saturation occurs For convenience Appendix A Specifications rates the probes in amp microseconds and provides an amp second curve for each probe To determine if your measurement exceeds the amp second product perform one of the following steps C Step 1 To determine the maximum allowable pulse width measure the peak current of the pulse see Figure 3 7 Divide the specified amp se cond or microsecond product of your probe by the measured peak current of the pulse The quotient is the maximum allowable pulse width The pulse width at the 50 point of the measured signal must be less than this value For example if a pulse measured with an A6302 probe had a peak current of 40 A the maximum allowable pulse width would be 100 A us divided by 40 A or 2 5 us Operation Maximum Imax Do Not Exceed Pulsed Current Pulse Width at 50 50 Pulse Width i at 50 50 Maximum Imax Continuous
41. m configurations The A6302 and A6303 probes may also be ordered sepa rately You can significantly extend the AC dynamic range of the A6302 Probe by using the CT 4 High Current Transformer The CT 4 can be ordered from your Tektronix sales representative For more information about using the CT 4 with the AM 503S system see Section 3 Operation 1 5 1 6 TM 502A Power Module The TM 502A Power Module is a lightweight portable power supply that operates on either 110 or 220 VAC 50 or 60 Hz and accepts up to two single width TM 500 instruments such as the AM 503A or TVC 501 Time to Voltage Converter Power Cord The power cord supplies power to the TM 502A Power Module Several options of the power cord are available see the power cord options list Output Cable The output cable a 50 O BNC cable connects the output of the AM 503A to your oscilloscope or measuring device 50 Q Termination Because the output impedance of the AM 503A is 50 Q the input imped ance of your oscilloscope must be 50 Q If the input impedance of your oscilloscope is 1 MQ attach the 50 O feed through termination to the oscil loscope input General Information Options AM 503S User Manual Toolbox The AM 5038 system includes a toolbox for storing probes cables acces sories and small tools The toolbox can be plugged into the TM 502A next to the AM 503A Amplifier User Manual and Quick Reference Card This user manual explains how
42. nspection Safety Summary AM 503S User Manual After carefully unpacking your AM 503S Current Probe System verify that you have all of the items for your system configuration as described in this manual If any item is missing consult your Tektronix representative for assistance Observe the safety precautions described in this summary when operating the AM 503S Current Probe System Specific warnings and cautions appear throughout the manual but may not appear in this summary Symbols and Terms These two terms appear in manuals statements identify conditions or practices that could result in damage to the equipment or other property m statements identify conditions or practices that could result in personal injury or loss of life 1 9 These two terms appear on equipment m CAUTION indicates a personal injury hazard not immediately accessible as one reads the marking or a hazard to property including the equip ment itself DANGER indicates a personal injury hazard immediately accessible as one reads the marking This symbol appears in manuals Static Sensitive Devices These symbols appear on equipment 7 A DANGER Protective ATTENTION High Voltage ground earth Refer to terminal manual General Information AM 503S User Manual Specific Precautions Observe all of these precautions to ensure your personal safety and to prevent damage to your equipment Power Source This product is d
43. nual describes how to operate the AM 503S Current Probe System with emphasis on the AM 503A Current Probe Amplifier A6302 Current Probe and A6303 Current Probe To obtain operating and servicing informa tion for the TM 502A Power Module refer to the TM 502A Instruction Manu al To obtain servicing information for the AM 503A A6302 and A6303 including a replaceable parts list refer to the AM 503S Service Manual Tektronix part number 070 8174 00 This manual uses the following conventions m AM 503S refers to a combination of a TM 502A Power Module an AM 503A Current Probe Amplifier and an A6302 or A6303 Current Probe m TM 502A refers to a TM 502A Power Module Power module refers to any Tektronix TM 500 or TM 5000 Series power module AM 503A refers to the AM 503A Current Probe Amplifier m A6302 refers to the A6302 Current Probe and A6303 refers to the A6303 Current Probe m Items in bold capital letters such as DC LEVEL represent a button knob indicator or connector on the AM 503A front panel m Items in bold such as 50 represent values displayed on the AM 503A front panel Notes appear throughout the manual They provide information that helps you get the best performance from your product NOTE Read note statements for helpful information Welcome Organization AM 503S User Manual This manual is divided into four sections and three appendices Section 1 General Information describes the comp
44. obe Slide 00 cece eee eee 3 8 Degaussing the Probes 0 cece eee ee eee es 3 12 Making Current Measurements se 3 13 DC Measurements ssss esses esee 3 13 AC Measurements sssssssessee eren 3 17 Probe Coupling Considerations uu 3 18 Probe Bandwidth Considerations 3 20 Maximum Current Limits of the Probes 3 21 Maximum Continuous Current essen 3 21 Maximum Pulsed Current 2 222222 cece eee eee ee eens 3 21 Amp Second Product 0000 cee ee cece 3 22 How to Extend the Measurement Range of the AM 503S 3 25 Extending the AC Range 00 cc cece eee eee 3 25 Extending the DC Range 2 2 2222 seen nenn 3 26 AM 503S User Manual vii viii How to Increase the Sensitivity of the AM 503S 3 29 Measuring Differential Currents or Current Nulls 3 31 Error Codes ui piv nn ee ete 3 33 Test Mod 4 oe eee he ial a tae ile te a 3 34 Maintenance seeseeeeee nennen 3 36 Applications 222 cee Rem Ie RE a 4 1 Automobile Charging Systems seeese 4 2 Inductance Measurements uu uueesus 4 6 Low Impedance Pulse Sources sssuuue 4 6 Higher Impedance Pulse Sources sssuuue 4 9 Measuring Inductor Turns Count 4 12 Continuity Test
45. on A digital readout should appear on the AM 503A front panel and a coupling light should come on see Section 2 Control Summary for the location of the coupling lights General Information Release Lever Figure 1 4 Installing the AM 503A Into the Power Module AM 503S User Manual 1 19 Packaging for Should you ever need to return an AM 503S component to Tektronix for Shipment repair attach a tag to it with the following information m name and address of owner m name ofa contact person at your firm m type of AM 5035 component and serial number m description of the service required If available reuse the original shipping carton and packing material when shipping the AM 503S component If the original carton is not available then wrap the instrument in anti static sheeting to reduce the risk of static damage and surface scratches and pack the instrument in a carton with specifications similar to the original If you have any questions about ship ping the instrument contact your Tektronix representative 1 20 General Information Customer Support To help you get the best performance from your AM 503S system Tektronix offers the following customer support services Service Support Should your AM 503S system need repair and you do not wish to service it yourself contact your nearest Tektronix Service Center Sales Support To order optional equipment and accessories call the Tektronix National Marketing Center at 1
46. onents included with the AM 5038 describes how to install and power up the system and provides general safety guidelines Section 2 Control Summary briefly describes the functions of the AM 503A front panel controls Section 3 Operation tells how to operate the AM 503S system and highlights specific operating considerations Section 4 Applications shows some typical applications of the AM 5038 Appendix A Specifications lists major specifications of the AM 503S Current Probe System Appendix B Glossary of Terms defines key technical terms used in this manual Appendix C Troubleshooting Guide lists possible solutions to some of the most common measurement problems iii iv Welcome Bi UU rr Contents AM 503S User Manual General Information Features Applications AM 503S System Components seese AM 503A Current Probe Amplifier 20 Current Probes sse rered eurrien iea A A TM 502A Power Module 2 22 2222 eee eee eee Power Cord Output Cable 50 O Termination 5i iss Toolbox User Manual and Quick Reference Card Options Power Cord Opti ONS osx escena centu a arate iu es ana Uu RR Optional Accessories 0cccceeee eee nun nn nun nn Initial Inspection 1 1 1 2 1 2 1 3 1 5 1 5 1 6 1 6 1 6 1 7 1 7 1 8 1 8 1 9 vi Safety Summary 00 0 ccc e cece eee eens 1 9 Symbols
47. oscope impedance is 1 MQ install a 50 Q feedthrough termination at the oscilloscope input connector not at the AM 503A output connector a 50 Q termination is supplied with the AM 5038 Failure to properly terminate the AM 503A will result in an error code 54 being displayed on the AM 503A front panel digital readout if you attempt to degauss autobalance the system Some optional power modules allow you to re route the plug in instrument output to the rear interface of the power module refer to the Tektronix catalog or your Tektronix sales representative The AM 503A can be confi gured for operation with these power modules Instructions for configuring Operation the AM 503A for rear interface operation are contained in the AM 503S Service Manual and should be performed only by qualified service person nel Test Oscilloscope AM 503A A6302 Probe 50 Q Input Figure 3 1 Connecting the AM 503A to an Oscilloscope AM 503S User Manual 3 3 Adjusting the Oscilloscope 3 4 After you have connected the AM 503A to the oscilloscope make the follow ing adjustments to the corresponding oscilloscope channel NOTE Before making any adjustments allow the equipment including the current probe to warm up for at least 20 minutes L Step 1 Setthe vertical gain of the oscilloscope to 10 mV div L Step 2 Set the oscilloscope ground reference so the trace appears at the center graticule line or
48. ristics Characteristic AM 503A with A6302 AM 503A with A6303 Bandwidth DC to 50 MHz DC to 15 MHz DC Measurement Accuracy 3 3 Rise Time lt 7 ns lt 23 ns A 2 Appendix A Specifications Table A 2 Nominal and Typical AM 503S Characteristics Characteristic Aberrations Amp Second Product Deflection Factor oscilloscope at 10 mV div Frequency Derating Insertion Impedance Low Frequency Limit AC coupled AM 503S User Manual AM 503A with A6302 5 100 x 10 100 A us see amp second curve in Figure A 2 1 mA div to 5 A div in 1 2 5 increments maximum continuous current rat ing decreases above 20 kHz see frequency derating curve in Figure A 1 0 1 Q at 1 MHz 0 5 O at 50 MHz see insertion impedance curve in Figure A 4 lt 7 Hz AM 503A with A6303 5 10 000 x 10 6 10 000 A us see amp second curve in Figure A 3 10 mA div to 50 A div in 1 2 5 increments maximum continuous current rat ing decreases above 20 kHz see frequency derating curve in Figure A 1 0 02 O at 1 MHz 0 15 O at 15 MHz see insertion impedance curve in Figure A 5 lt 7 Hz A 3 Table A 2 Nominal and Typical AM 503S Characteristics Cont Characteristic AM 503A with A6302 AM 503A with A6303 Maximum Continuous Current 20 A DC peak AC 100 A DC peak AC derated with frequency 14 14 Anus 70 7 Arms see Figure A 1 Maximum Pulsed Current 50A 500 A not to exc
49. rrent division scale factor In the unlikely event an instrument failure occurs the display will flash an error code number ranging from 10 to 88 NOTE The AM 503A front panel digital readout will display error code 54 if the AM 503A is not properly terminated into 50 Q at the oscillo scope input Refer to Connecting the AM 503A to an Oscillo scope in this section for more information If the AM 503A is totally inoperative a seven segment readout inside the AM 503A may display an internal error code ranging from 1 to 5 If an error code other than 54 appears turn the instrument off and then on again If the error condition persists have the instrument serviced by qual ified service personnel For a definition of error codes refer to the AM 503S Service Manual AM 503S User Manual 3 33 Test Mode 3 34 When the internal backup battery becomes weak the CURRENT DIV dis play will momentarily flash the characters LO when the instrument is turned on For battery replacement instructions refer to the AM 503S Service Manual In addition to normal operation the AM 503A has a test mode which is used exclusively for servicing the instrument The test mode is briefly mentioned here so that you can recover should you accidentally initiate it for more information about the test mode refer to the AM 503S Service Manual Do not run test mode routines Some routines can destroy RAM data and impair instrument operation Test mod
50. s 4 5 Figure 4 3 Measuring Inductance with a Low Impedance Source 4 7 Figure 4 4 Linear Current vs Time Ramp ssssessssss 4 8 Figure 4 5 Measuring Inductance with a High Impedance Source 4 10 Figure 4 6 High Impedance Source Current Ramp 4 11 Figure 4 7 Measuring the Number of Turns in a Coil 4 13 Figure 4 8 Turns Measurement Using Reference Coil 4 14 Figure A 1 Frequency Derating Curves uuuuusssss A 8 Figure A 2 A6302 Amp Second Product Curve A 9 Figure A 3 A6303 Amp Second Product Curve A 10 Figure A 4 A6302 Insertion Impedance Curve A 11 Figure A 5 A6303 Insertion Impedance Curve A 12 Figure A 6 Probe Jaw Dimensions 00 0c eee A 13 Contents Bi WU LLL ATL List of Tables Table A 1 Warranted AM 503S Characteristics Table A 2 Nominal and Typical AM 503S Characteristics AM 503S User Manual Table A 3 AM 503S Environmental Characteristics Table A 4 AM 5038 Physical Characteristics A 2 A 5 A 6 xi xii Contents Igi ip u l1 VU LI L General Information AM 503S User Manual The Tektronix AM 503S Current Probe System consists of an AM 503A Current Probe Amplifier an A6302 Current Probe the A6303 Current Probe may be ordered separately or as an option and a TM 502A Power Module The AM 5038 lets you use one probe to
51. s and the oscilloscope shows a reading of 5 mA DC the actual current flow is 5 mA divided by 5 or 1 mA DC NOTE Winding multiple turns around the probe increases insertion induc tance and reduces the upper bandwiath limit of the probe AM 503S User Manual 3 29 Conductor Under Test Extra Turns for Increased Sensitivity A6302 Current Probe Figure 3 9 Increasing Probe Sensitivity 3 30 Operation Measuring Differential Currents or Current Nulls AM 503S User Manual You can use two AM 503A amplifiers two identical current probes and a differential amplifier with your oscilloscope to measure differential current however you can also measure differential current or adjust current nulls with just one AM 503A amplifier and one current probe by performing these steps C Step 1 Orient the two conductors under test so that the polarities oppose each other and clamp the current probe around them see Figure 3 10 L Step 2 Measure the current The polarity of the displayed measure ment indicates which conductor is carrying the greater current L Step 3 To adjust for a current null adjust the current in one of the conductors until the displayed measurement is zero 3 31 d Conductor 2 Conductor 1 MS c Gene SS A6302 Current Probe Figure 3 10 Measuring Differential Current and Nulls 3 32 Operation Error Codes During normal operation the digital readout of the AM 503A displays the cu
52. tine perform these steps C Step 1 Verify that the current probe is connected to the AM 503A and removed from the conductor under test L Step 2 Lock the probe slide see Figures 3 3 and 3 4 C Step 3 Press the PROBE DEGAUSS AUTO BALANCE button NOTE The AM 503A front panel digital readout will display an error code 54 if the AM 503A is not properly terminated into 50 Q at the oscilloscope input Refer to Connecting the AM 503A to an Oscil loscope in this section for more information Operation Making Current Measurements AM 503S User Manual To maintain measurement accuracy degauss your probe for each of these circumstances after turning the AM 503A on and allowing a 20 minute warm up period before connecting the probe to a conductor or changing conductors whenever an overload condition occurs whenever the probe is subjected to a strong external magnetic field You should degauss the probe periodically during use Failure to degauss the probe is a leading cause of measurement errors After you have completed the oscilloscope adjustments and the AM 503S degauss autobalance procedure your system is ready to measure current This section describes how to make DC and AC measurements for more measurement examples see Section 4 Applications DC Measurements To measure DC current perform these steps L Step 1 Verify that the vertical gain of the oscilloscope is 10 mV div the input coupling is DC an
53. to use the AM 503S current measurement system The quick reference card provides an annotated front panel illustra tion lists several important operating guidelines and lists the essential steps for making a current measurement Service information for the A6302 and A6303 Current Probes and the AM 503A Current Probe Amplifier is provided in the AM 503S Service Manual Operating and servicing instruc tions for the TM 502A are in the TM 502A Instruction Manual You can order the following options for the AM 5038 Current Probe System Option 01 Add the A6303 Probe Option 03 Substitute the A6303 Probe for the A6302 Probe 1 7 Power Cord Options Optional Accessories 1 8 You can order the following power cord options for the AM 503S Current Probe System Option Al Universal European 220 V Option A2 United Kingdom 240 V Option A3 Australia 240 V Option A4 North America 240 V Option A5 Switzerland 220 V You can order the following optional accessories for the AM 503S Current Probe System m AM 5038 Service Manual Tektronix part number 070 81 74 00 m Current Loop Tektronix part number 015 0601 50 The AM 5088 Service Manual provides information for testing calibrating and troubleshooting your AM 503S system The current loop is used for checking the performance characteristics of the AM 5038 Refer to the AM 503S Service Manual for more information about these accessories General Information Initial I
54. unlocked or disconnected from the AM 503A the PROBE OPEN indicator will light Figure 3 3 illustrates the slide operation of the A6302 probe To open the probe pull the slide back until the jaw is open To lock the probe push the slide forward until the detent snaps into place Figure 3 4 illustrates the slide operation of the A6303 probe To open the probe press the bottom of the lock button and squeeze the handle until the core is open To lock the probe release the squeeze handle and press the top of the lock button Operation AM 503S User Manual The exposed core pieces are not insulated To avoid equipment damage remove power from an uninsulated wire before clamping the current probe around it 3 10 Probe Open Figure 3 3 Operating the A6302 Current Probe Slide Operation 1 Unlock the probe P Release squeeze handle 2 Squeeze the handle a Opening the Probe b Closing and Locking the Probe Figure 3 4 Operating the A6303 Current Probe Slide AM 503S User Manual 3 11 Degaussing the Probes Before measuring current perform the probe degauss autobalance routine Degaussing the probe removes residual magnetism from the probe core Magnetism can introduce a measurement error such as an extraneous DC offset Autobalancing removes unwanted DC offsets in the amplifier circuitry The AM 503A combines and automates these functions in one button To initiate the degauss autobalance rou
55. utput m The measurement exceeds the amp second product of the probe see Section 3 Operation for more information about amp second product If possible upgrade to a probe with a higher current rating or use a CT 4 transformer m Bandwidth limit is turned on Verify that bandwidth limit switches of both the AM 503A and the oscilloscope are set to the full bandwidth position AM 503S User Manual C 5 Appendix C Troubleshooting Guide BR I Index A AC coupling 2 8 3 17 3 18 accessories 1 3 adjustments AM 503A 3 13 oscilloscope 3 4 amp second product 3 22 B 1 applications 4 1 auto balance B 1 B bandwidth limits 2 9 3 20 battery low indicator 3 33 AM 503S User Manual bucking current 3 26 B 1 BW LIMIT switch 2 9 C CAUTION statement in manuals 1 9 statement on equipment 7 70 changing the operating voltage 1 13 choosing a probe 3 5 continuity measurements 4 15 control summary 2 1 conventional current flow B 2 coupling modes 3 18 COUPLING switch 2 8 current limitations amp second product 3 2 maximum continuous 3 21 maximum pulsed 3 21 CURRENT DIV switch 2 8 customer support 1 21 D DANGER statement on equipment 1 10 DC coupling 2 8 3 18 DC LEVEL control 2 3 3 15 3 18 degauss function 2 6 3 12 B 2 E error codes 3 33 error 54 3 2 C 1 LO C 1 extending the current range of the probes 3 25 F frequency derating 3 27 front pane
56. y certified for such operation Do Not Remove Covers or Panels To avoid personal injury do not remove the product covers or panels Do not operate the product without the covers and panels properly installed General Information Operating Temperature Operating Voltage AM 503S User Manual The AM 503A Current Probe Amplifier can be operated in ambient tempera tures between 0 C and 50 C and stored in ambient temperatures from 55 C to 75 C If stored at temperatures outside the operating limits allow the chassis to reach the specified operating temperature range before applying power The TM 502A Power Module can operate from one of four AC line voltages The operating voltage is determined by the voltage selector located on the rear panel of the TM 502A see Figure 1 2 To avoid personal injury or equipment damage do not connect the power module to the AC line receptacle or turn the power module on until you have verified that the proper operating voltage is selected Selector Window 120 M Latch Voltage Selector Pij Lyi sA TM 502A Power Module Figure 1 2 TM 502A Voltage Selector 1 14 General Information The value displayed in the voltage selector window should match the value of your line voltage If the two values don t match perform these steps to select the correct value L Step 1 Push up on the latch and pull the voltage selector assembly out
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