Working principle and operating steps of an insulation multimeter
Overview: An insulation multimeter is a functional instrument used by technical personnel to verify the quality of electrical equipment, ensure that the equipment meets regulations and standards, determine changes in equipment performance over time, and determine the cause of faults by conducting insulation resistance tests on conductors, electrical parts, circuits, and devices.
1、 Importance of insulation resistance measurement
Maintenance technicians use insulation resistance testing to minimize the probability of equipment failure or malfunction and maximize production efficiency. At the same time, it can also prevent the occurrence of dangerous accidents such as electric shock and fire, ensuring the personal safety of employees.
2、 Insulation resistance measurement process
Before using an insulation common meter for testing, technicians must first conduct basic voltage, current, and resistance measurements.
After the equipment is powered off, use a FLUCK insulated multimeter to determine the integrity of the windings or cables in the motor, transformer, and switchgear. Measure the insulation resistance and leakage current of the insulation material to generate an insulation resistance value.
3、 Safe operation
（1） Before testing
1. Work on uncharged circuits as much as possible, using appropriate locking/marking procedures
2. Assuming that the tested circuit is live, use appropriate personal protective equipment and safety tools.
3. Remove all jewelry and stand on a rubber insulated school.
（2） During testing
1. Do not connect insulated public meters to live conductors or equipment, and strictly follow the manufacturer's recommendations.
2. Turn off the tested equipment through an open circuit fuse, switch, or circuit breaker. Lock and label the tested device.
3. Disconnect branch wires, grounding wires, and all other equipment from the tested unit.
4. Before and after the test, discharge the conductor capacitance separately.
3、 Precautions
1. Check all leakage currents in the de excitation circuit through fuses, switching devices, and circuit breakers. Leakage current can cause inconsistent and incorrect readings.
2. Since the instrument will generate electric arc when the insulation is damaged, please do not use the insulation resistance tester in dangerous or explosive gas environment.
3. Do not use an insulation resistance tester on electronic devices.
4. Please use insulated rubber gloves with leather protection when connecting the test line.
4、 Maintenance principle
（1） When installing and updating equipment
It will avoid wiring errors and defective equipment in the system, ensure high-quality installation, and prevent electric shock or equipment fire.
（2） Eliminate hazards
By conducting high-voltage insulation resistance tests between the current carrying wire and the grounding wire, maintenance personnel can eliminate the possibility of dangerous short circuits or short circuits to ground.
（3） Preventive
Using an insulation multimeter for routine monitoring of insulation resistance values can provide information on insulation degradation status, ensuring timely repair or replacement of equipment.
