MICROHMMETER CA-10
Contents
1. LCD 6 LOW and CHARGING indicators of battery condition Measurementcurrent FAULT indicator Thermal safety THERMAL PROTECTION indicator Power supply mounted socket for connection of the battery charger lead Directly accessible screwed fuse holder 6 INDICATORS 6 1 BATTERY e LOW CIRCUTOR MICROHMMETER CA 10 Page N25 The battery voltage is permanently checked When it is getting low the flashing red LOW indicator warns the user that there is only enough power for a few measurements It becomes urgent to charge the battery If the user reaches the limit of battery use the red LOW light stops flashing the instrument is out of service and will not make any more measurements It is then essential to recharge the battery Once the battery is recharged press the ON OFF button twice to switch on the instrument again e CHARGING The green CHARGING light indicates that the battery is currently being recharged This indicator will remain lit as long as the instrument is connected to the power supply 6 21 VALIDATING MEASUREMENT e FAULT e The current input by the instrument into the measurement circuit is electronically checked The FAULT light comes on in the two following cases If this current is null open circuit or protective fuse in the instrument has blown The user must check the circuit clamp contact condition of the resistance condition of the two fuses because2. m CIRCUTOR MICROHMMETER CA 10 Cod 7 70 118 USER S MANUAL M981184 99A GB oc CIRCUTOR S A aj CIRCUTOR MICROHMMETER CA 10 Page N 1 1 SAFETY PRECAUTIONS 1 1 MEASUREMENT Before any measurement check that the resistance to be tested is not live Check that the battery has a charge sufficient for the reguirements of the measurement otherwise recharge it 1 2 MAINTENANCE To preserve the service life of the battery take care not to exceed a charge time longer than 14 h for a completely discharged battery Before opening the case check that the instrument is disconnected from any supply source When replacing the battery reconnect the wires according to the polarity red and black When reclosing the case reconnect the linking cables connecting the supply board on the back of the case to the upper board mounted on the chassis 2 PRESENTATION The CA 10 MICROHMMETER is a portable 2000 count digital onmmeter designed for the measurement of very low resistance values Presented in a robust worksite case the CA 10 MICROHMMETER is an autonomous instrument powered by a cadmium nickel battery with a dual voltage charger 110 V 220 V incorporated 6 ranges from 0 2000 uQ to 200 are available to the user The CA 10 MICROHMMETER operates according to the 4 wire method a DC current is injected through the resistance under test a measurement of voltage U is made at the terminals of
3. 1 digit on the left of the display indicates range overload so you should change to a higher range Nevertheless if the digit 1 is still displayed even on the highest range 200 Q 0 01A this means that the value of the resistance under test is above 199 9 Q max value of the measurement range of the instrument CIRCUTOR MICROHMMETER CA 10 Page N 8 e To obtain higher accuracy reduce the range and on the range switch read the value of the test current corresponding to this new range to guard yourself against problems due to the injection of a current that is too high e To switch off the instrument press the ON OFF button again the display should then go out NOTE During any operation it is important to keep a watch on the different indicators which were explained on LED INDICATORS 8 2 VERY LOW RESISTANCES When measuring very low resistances the presence of thermal electromotive forces can reduce the accuracy of the measurement You can eliminate their effect by reversing the direction of the current The real measurement will then be obtained by taking half the value of the sum of the absolute values of the and readings as indicated below e Take anormal measurement as described in In general see preceding paragraph IN GENERAL and note down the value A displayed By definition the range will be 2000 uQ because you are making a test of very low resistance e Press the inver
4. the measurement isn t valid Note that if the circuit isn t re closed after approx 4 minutes the instrument switches off automatically If the measured resistance is very high in relation to the range used The user should then change to the higher ranges 6 3 THERMAL PROTECTION 6 e THERMAL PROTECTION For the 2000 uQ range 10 A thermal protection of the electronics is provided by an internal thermostat which interrupts the 10 A current in the case of prolonged use When overheating the THERMAL PROTECTION indicator lights and blocks the 2000 uQ range The other ranges are nevertheless usable The 2000 uQ range will again be accessible as soon as the light goes out approx 10 minutes 7 ELECTRICAL PROTECTION Protection of the instrument from incorrect use is by oversized sensitive components and by fuses accessible from the front panel The fuses F1 and F2 see 10 p 6 with a high breaking capacity provide good protection for the instrument in case of incorrect connection by the operator CIRCUTOR MICROHMMETER CA 10 Page N 6 380 V rms applied to the socket terminals two by two in any order To make a rapid test of the fuses simply short circuit terminals C1and C2 see 1 p 6 and switch on the instrument by pressing the ON OFF button see 3 p 6 If the FAULT light comes on this confirms that at least one of the two fuses F1 or F2 is blown In this case replace the blown fuse with o
5. The charger is protected against incorrect programming of the power supply by internal electronic protection f this protection comes into play wait approx one minute before switching on the charger again The cooling time of the protective varistance Voltages permissible on the charger 187 V to 253 V 230 V rated frequency 47 Hz to 450 Hz 94 V to 127 V 110 V rated frequency 47 Hz to 450 Hz Battery charge time 14 hours for a completely discharged battery Number of charge discharge cycles more than 300 cycles Once the battery has been recharged press ON OFF twice to switch on the instrument again NOTE During charging measurement is possible Wait for the instrument to come on according to the condition of the battery then make measurements The charger capacity 800 mA makes it possible to use the 20 42200 uQ 2000 uQ 20 Q 200 Q ranges continuously and the 2000 uQ range temporarily CIRCUTOR MICROHMMETER CA 10 Page N 10 9 2 REMOVING THE LID To unclip the lid of the case apply vertical pressure to the back of the lid while holding it 9 3 OPENING THE CASE To open first remove the lid then use the allen key which is in the pouch in the lid of the case Unscrew the six screws holding the chassis located under the case Me ai a e y CS Wit PAO oo T lt ta he eo NA FONT tava Le NA x f A ES S Sa De V g aill I a st 3 sii a ei eae P Lift away th
6. digits 18 mm height good readability down to 1 lux 1 s on the left of the display indicates range overload On the left of the display indicates a reversal of connection of the measuring leads crossing the voltage or current leads e 2second time constant approx for the display to settle whatever the resistance being measured example inductive winding CIRCUTOR 4 ELECTRICAL SPECIFICATIONS MICGROHMMETER CA 10 Page N 3 e Max permitted overload on the measurement terminals 380 V rms e Protection by HBC 380 V fuse and oversized sensitive parts class 2 instrument to CEI 348 rated insulation voltage 250 V rms e Minimum dielectric strength 1500 V for the terminals and 3000 V for the power socket e Electrostatic discharge level 2 4 kV to CEI 801 2 e Radiated field level 2 3 V m to CEI 801 3 e Electric shocks on supply socket level 4 8kV to CEI 801 5 4 1 MEASUREMENT RANGES Ranges 0 2000uUQ 0 200Q 0 200uUQ 10 20004 0 200 0 200Q Resolution 1pyuQ 1048 10048 1uQ 1048 100428 Measureme 10A 1A 1A 100mA 10mA 10mA nt current Typical 0 25 0 25 0 25 0 25 0 25 0 25 accuracy in reading reading reading reading reading reading the 2 1 count 1 1 count 1 count 1 count reference counts count conditions Accuracy 0 5 0 5 0 5 0 5 0 5 0 5 max in the reading reading reading reading reading reading reference t2 counts 1 coun
7. e chassis without forgetting to disconnect the linking cables 1 and 2 connecting the power supply board located at the bottom of the case to the upper board fixed on the chassis CIRCUTOR MICGROHMMETER CA 10 Page N 11 9 4 CHANGING THE BATTERY e Affer having dismantled the base plate see p 33 OPENING THE CASE unscrew the two butterfly screws on the battery support e Rernove the battery support plate e Disconnect then remove the battery and exchange it for the recommended battery BATTERY N 2 Cd Ni reference P01 2960 12 Buttertly Support Programming the a plate of Supply voltage batterie 110 V 220 V able 2 Link cable 1 9 5 CLEANING THE CASE Preferably use a soft cloth moistened with soapy water Avoid using alcohol or oil based products 9 6 CALIBRATION It is essential that all measuring instruments are regularly calibrated For occasional daily use we recommend that an annual check be carried out When the instrument is used continuously every day we recommend that a check is made every 6 months 9 7 REPAIR Maintenance repairs under or out of guarantee Please return the product to your distributor
8. ne of the correct type and value 8 A 380 V 8 OPERATING PROCEDURE 8 1 IN GENERAL e Check that the resistance to be tested isnt live e Switch ON the instrument by pressing the ON OFF button CIRCUTOR MICROHMMETER CA 10 Page N27 Connect the resistance to be measured according to the diagram shown next to the measurement terminals 0 With the instrument operating according to the 4 wire method check the correct position of the uoltage measurement points To do this apply the voltage measurement instruments the 10 A clamps supplied with the instrument can be used both to input the measurement current and to measure the voltage at the precise points defining the resistance terminals Oc cys O P2 Oc2 The value displayed by the CA 10 MICROHMMETER corresponds to the resistance of the dotied part e Select the measurement range using the range switch The user should be aware that the choice of a low measurement range implies a high test current e f you don t know the order of magnitude of the resistance we advise using the highest range 200 0 0 01A e Read the value on the LCD directly in the unit indicated by the range switch e The appearance of the sign on the left of the display indicates poor connection of the measurement leads crossing the voltage or current leads Simply change over the current connections C1 and C2 or the voltage terminals P1 and P2 e The appearance of the
9. t 1 count 1 count 1 count 1 count 4 2 REFERENCE CONDITIONS e Ambient temperature 23 C 3 C e Relative humidity 40 to 60 HR e Supply voltage 6 V 0 1 V 4 3 VARIATION IN THE WORKING RANGE Type of Limits of working range Average variation of the measurement in relation to distortion the reference conditions Typical Max Temperature 10 Cto 55 C 0 1 measur 10 C 0 25 measur 10 C Humidity 10 to 90 0 5 max in the range working Voltage 4 5V a7V 0 1 0 15 e Transportation and storage temperature 20 C to 55 C 5 DESCRIPTION Cod 7 70 118 CIRCUTOR MICROHMMETER CA 10 Page N 4 MICROHMMETER CA 10 oo a 3 1 Avan oS of Ns x A Ci 910 eS Se er 10 2 3 4 big terminals for connection with 4 mm diameter plugs or by spade clips tightened under the terminals C1 and C2 correspond to the current outputs P1 and P2 to voltage measurements The terminals are marked by colours corresponding to those of the connection accessories C1 and P1 are red P2 and C2 are red P2 and C2 are black Rotary switch with 6 positions to select the range and the measurement current from 2000 pQ 1 0 A to 200Q 0 01A 8 ON OFF button for switching the instrument ON OFF nvertor to invert the measurement current to take into account the possible presence of thermal electromotive forces principally for the 2000 pQ range
10. the resistance The instrument then displays the value of the resistance corresponding to the ratio U I The CA 10 MICROHMMETER has as its principal application the precise measurement of the resistance of the windings of rotary machines or transformers switch contacts motor collectors cable junctions solder points 3 GENERAL FEATURES 3 1 CASE e Work site plastic case with 50 glass aj CIRCUTOR MICROHMMETER CA 10 Page N22 e Protection rating to CEI 529 IP 520 lid open IP 543 lid closed e Dimensions 390 x 260 x 250 L x x H e Mass approx 8 kg 3 2 POWER SUPPLY e Cadmium nickel battery 6 V 7 A h rechargeable on mains supply with incorporated dual voltage charger 110 V 220 V e Automatic power cut out if the current terminals are in the air for more than 4 minutes approximately e Voltage operating range 4 5 V to 7 V 3 3 SERVICE LIFE e 200 to 300 measurements of 8 seconds with a measurement current of 10 A e Approx 900 measurements of 30 seconds with a measurement ourrent of 1 A e Approx 5000 measurements of 30 seconds with a measurement current less than or equal to 0 1 A e The LOW indicator shows when flashing a remaining service life sufficient for about 10 measurements at 10 A and more than 100 for the others 3 4 CONNECTION e Four large terminals for 4 mm diameter banana plugs or spade connectors with a minimum opening of 6 mm 3 5 DISPLAY e 2000 counts 7 segments LCD 3
11. tor see 4 p 6 changing it from the high position 1 to the low position 1 and hold it for the time required ta note down the displayed value B This should be preceded by the sign indicating that you have reversed the measurement current e Make the following calculation IAI IBI e The result of this calculation gives the precise value of the resistance tested overcoming problems of interference voltages in the measurement circuit NOTE To benefit from all the accuracy guaranteed by the instrument take measurements taking care to make the current lines homogeneous in the measured zone CIRCUTOR MICROHMMETER CA 10 Page N 9 9 MAINTENANCE 9 1 RECHARGING THE BATTERY e The incorporated battery is dual voltage 110 V 220 V switching is done inside the instrument by a sliding switch on the supply board e A small plate fastened by screws below the charger socket on the front panel indicates the voltage that the charger is programmed for e Check that the supply voltage matches the voltage marked on the voltage supply plate e Ifthe programming of the charge voltage has to be changed then this little plate should be turned over so that it always matches the programmed voltage and the voltage indicated on the front e panel e Connect the power lead to the socket e Once the lead has been connected to the power supply the CHARGING light comes on indicating that the battery is being charged e
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