User Guide Model 380260 Insulation Tester / Megohmmeter
Contents
1. This section applies to any device under test that uses a line cord For double insulated power tools the meter s leads should be connected to the device s housing chuck blade etc and the lines of the power cord Testing AC Motors Disconnect the motor from the line by disconnecting the wires from the motor terminals or opening the mains switch If the mains switch is opened and the motor also has a motor starter then the starter must be held in the ON position With the mains switch opened the measured resistance will include the resistance of the motor wire and all other components between the motor and the main switch If a weakness is indicated the motor and other components should be checked individually If the motor is disconnected at the motor terminals connect one meter lead to the grounded motor housing and the other lead to one of the motor leads Refer to diagram at below GND i 3 Notes no 1 The STARTER must be in the ON position during the test 2 The motor to meter connection must be made to the motor housing ground 3 The meter to main switch connection must be to the motor side of the main switch as shown Testing DC Motors 1 2 Disconnect the motor from the line To test the brush rigging field coils and armature connect one meter lead to the grounded motor housing and the other lead to the brush on the commutator If the resistance measureme2. User Guide EXT INSTRUMENTS Model 380260 Insulation Tester Megohmmeter UC 10 J Introduction Congratulations on your purchase of Extech s Insulation Tester Megohmmeter The Model 380260 provides three test ranges plus continuity and AC DC voltage measurement A handy test lock feature and a data hold function are also included This professional meter with proper care will provide years of reliable service Safety 1 Circuits under test must be de energized and isolated before connections are made except for voltage measurements 2 Circuit connections must not be touched during a test Use extreme caution when working near bare conductors and bus bars Accidental contact with conductors could result in electrical shock Use caution when working near voltages above 60VDC or 30VACrms After insulation tests capacitors must be discharged 5 Test leads including alligator clips must be in good working order clean and without broken or cracked insulation 6 When servicing use only specified replacement parts International Safety Symbols A Caution refer to this manual before using this meter A Dangerous Voltages O Meter is protected throughout by double or reinforced insulation Meter Description LCD Display Hold Button Test Button Rotary Switch Backlight Button Lock Button Noo Pp N Input Terminals 2 Model 380260 EU Version 2 0 4 06 Operation Warn
3. d 1000V 10 0 Range Test Current Short Circuit Current 200MQ 250V 250kQ load 200MQ 500V er 500kQ load SAA 0 1000MQ 1000VDC 1000 2000M 2 1000VDC Me AC VOLTAGE 40Hz 400Hz Range Resolution Accuracy Input Overload Impedance Protection 750VAC 1V 1 2 10d 10MQ 750Vrms DC VOLTAGE Range Resolution Accuracy Input Overload Impedance Protection 1000VDC 1V 0 8 3d 10MQ 1000Vrms 6 Model 380260 EU Version 2 0 4 06 RESISTANCE Range Resolution Accuracy Max Open Overload Circuit Voltage Protection 2000 0 10 1 2d 4 5V 250Vrms 200kQ 0 1kQ 1 2d 3V 250Vrms General specifications Display Sampling rate Continuity beeper Over range indicator Zero adjust Low battery indicator Environmental Power source Operating conditions Storage conditions Dimensions Weight IEC 1010 Approvals LCD with dual display 2 5 readings per second lt 400 short circuit current lt 200mA open circuit voltage 4 5V T displayed Automatic Low battery symbol displayed when battery voltage is low Installation category II Pollution Degree 2 Altitude up to 2000 meters Indoor use only Six 6 1 5 AA batteries 32 to 104 F 0 to 40 C 80 RH 14 to 140 F 10 to 460 C lt 80 RH 7 8 x 3 6 x 1 9 200 x 92 x 50mm 24 60z 700g CAT III 1000V CE 7 Model 380260 EU Version 2 0 4 06 Maintenance Battery Replacement When the low battery symbo
4. ed Press and hold the TEST button The upper right display shows the test voltage applied and the flashing high voltage symbol 4 will be displayed The main display shows the resistance 5 Keep the test leads connected to the equipment under test and release the TEST button The circuit will discharge through the meter Keep the test leads connected until the circuit is completely discharged and the upper right display shows 0 volts Lock Function For hands free operation use the LOCK feature 1 With the test leads connected to the equipment under test simultaneously press the TEST and LOCK keys 2 The LOCK icon Lock will appear on the display A beeper will sound every 2 seconds to indicate that the meter is in Lock mode 3 Press the LOCK key to disable the Lock function and end the test 3 Model 380260 EU Version 2 0 4 06 Notes on IR Megohmmeter testing 1 The maximum measurement range for the 380260 is 2000MQ Frequently insulation resistance will exceed this value When this happens the display will indicate 1 meaning the resistance is very high and the insulation being tested is good 2 Ifthe device being tested is highly capacitive the display will indicate an increasing resistance value over time Always wait until the reading has stabilized before recording the value AC DC Voltage Measurement 1 Set the Rotary switch to the ACV or DCV position 2 Connect the red test lead to the VQ terminal a
5. ing Ensure that the circuit under test does not include components that can be damaged by 1000VDC such devices include power factor correction capacitors low voltage mineral insulated cables electronic light dimmers and ballasts starters for fluorescent lamps Connecting Test Leads For all measurements connect the red test lead to the VQ input terminal and the black test lead to the COM input terminal Test Lead Check Set the rotary switch to the 200Q range Touch the test lead tips together Resistance should read less than 0 5Q and the audio tone should sound With the leads not touching the display should read infinity indicated by 1 BR R NA Readings displayed other than the readings described above are indicative of a test lead problem The test leads must be replaced before using the meter Failure to do so could result in damage to equipment and electrical shock Insulation Resistance Measurements Megohmmeter Tests Warning Do not perform Insulation Resistance measurements if AC Voltage is present on the device under test 1 Connect the red test lead to the VQ input terminal black lead to the COM terminal Set the function switch to the desired MQ test voltage position 3 Connect the tips of the test leads to the equipment under test If there is a voltage present a constant beep will sound and the voltage will be displayed 4 The display will show 1 until the TEST button is push
6. l appears on the LCD the six 1 5V AA batteries must be replaced 1 Turn the meter off and remove the test leads 2 Unsnap the tilt stand from the rear of the meter 3 Remove the four Phillips head screws holding the battery cover A 4 Remove the battery compartment cover si 5 Replace the batteries observing polarity 6 Affix the rear cover and secure the screws p 7 Reattach the tilt stand e mej Cleaning Periodically wipe the case with a dry cloth Do not use solvents or abrasives to clean this instrument Copyright O 2006 Extech Instruments Corporation All rights reserved including the right of reproduction in whole or in part in any form 8 Model 380260 EU Version 2 0 4 06
7. nd the black test lead to the COM terminal 3 Connect the test leads to the circuit under test Read the voltage value on the LCD Resistance Measurement WARNING Do not run this test unless ACV 0 Do not use this mode to check diodes Set the Rotary switch to the 200kQ position Connect the red test lead to the VQ terminal and the black lead to the COM terminal Connect the tips of the test leads to the circuit under test SiN 4 Read the resistance value on the display Low Resistance Continuity Measurement 1 Set the Rotary switch to the 2000 position 2 Connect the red test lead to the VQ terminal and the black lead to the COM terminal 3 Connect the tips of the test leads to the circuit under test 4 Read the resistance value on the display When the resistance of a circuit is less than approx 40Q the audible tone will sound Auto Power Off To conserve battery life the meter will automatically turn off after approx 15 minutes of non use To turn the meter back on turn the rotary switch to OFF then to the desired function Hold Function The hold function freezes the reading in the display Press the HOLD key momentarily to activate or to exit the hold function Backlight Press the key for to turn on the display backlight function The backlight will automatically turn off after 15 seconds 4 Model 380260 EU Version 2 0 4 06 Applications Measuring Power Tools and Small Appliances
8. nt indicates a weakness raise the brushes off of the commutator and separately test the armature field coils and brush rigging one at a time Leave one lead connected to the grounded motor housing while testing the motor components This also applies to DC Generators 5 Model 380260 EU Version 2 0 4 06 Testing Cables 1 Disconnect the cable under test from the line 2 Disconnect the opposite end of the cable to avoid errors as a result of leakage from other equipment 3 Check each conductor to ground and or lead sheath by connecting one meter lead to ground and or lead sheath and the other meter lead to each of the conductors in turn 4 Check insulation resistance between conductors by connecting meter leads to conductors in pairs Refer to diagram at right In the diagram note that the 3 conductor cable has two wires shorted to the ground shield This two wire shield connection is then connected to one side of the meter The remaining conductor is connected to the other side of the meter Specifications Range Specifications Accuracies are specified as reading digits at 23 C 5 C lt 80 RH MEGOHMMETER RANGES Range Resolution Accuracy Terminal Voltage 200MQ 250V 0 1MQ 3 5d 250V 10 0 200MQ 500V 0 1MQ 3 5d 500V 10 0 0 1000MQ 1000VDC 1MQ 3 5d 1000V 10 0 1000 2000M 2 1000VDC 1MQ 5 5
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