I. Insulation resistance tester powered by hand-cranked generator
1. It is forbidden to measure insulation resistance during lightning or near high-voltage equipment, and the insulation resistance tester cannot be used to measure the insulation resistance of live equipment, otherwise it will damage the measured object or the insulation resistance tester;
2. When using the insulation resistance tester, it should be placed on a stable and firm place, and kept away from large external current conductors and external magnetic fields;
3. Correctly select a meter with appropriate range for measurement. When measuring the insulation resistance of high-voltage equipment, a high-voltage insulation resistance tester should be used; otherwise, a low-voltage insulation resistance tester should be used;
4. The insulation resistance tester generally has three terminals, marked L (line), E (ground), and G (shield). L is connected to the conductor part of the measured object that is insulated from the ground, E is connected to the shell or ground of the measured object, and G is connected to the shield ring of the measured object;
5. The external connection wires of the insulation resistance tester should be single wires with good insulation, and it is not advisable to use twin wires or twist the external connection wires together;
6. When using the insulation resistance tester, first check whether the instrument itself leaks electricity. The specific method is: check whether the pointer points to zero and infinity when the ground wire and the "line" terminals are short-circuited and open-circuited; during measurement, uniformly shake the generator handle, generally at about 120 r/min, and read after it stabilizes.
7. When measuring, the shaking speed of the handle should start from slow to fast, reach and stabilize at 100~140 r/min, and read only after the pointer stabilizes; only then is the reading correct.
8. When the measured object is a capacitive load, after obtaining the reading from the insulation resistance tester, it is not advisable to stop turning the handle immediately. Instead, gradually reduce the speed while removing the wire from the line terminal to avoid damaging the insulation resistance tester due to discharge of the capacitive load after the handle stops immediately. In addition, before measuring a capacitive load, the residual charge should be discharged to ensure operation without electricity.
9. When testing the insulation resistance of electrical equipment, the temperature, humidity, etc. during measurement should be recorded for analysis of the measurement results.
10. Before the insulation resistance tester stops rotating or the measured equipment is discharged, it is strictly forbidden to touch it by hand. When disconnecting wires, do not touch the metal parts of the leads.
11. After measurement, wait until the generator inside the meter stops rotating before disconnecting the wires, and discharge the measured object on site.
II. Insulation resistance tester powered by battery
When using this type of insulation resistance tester, pay attention to the following points:
1. Confirm that the measured object is safely grounded and not live.
2. Confirm that the E terminal (ground terminal) of the meter is grounded.
3. After testing, turn off the high voltage and working power supply in time. Keep the external surface clean, and wipe with a clean cloth if necessary. If the meter is not used for a long time, the battery must be removed to prevent corrosion of the instrument, and the meter should not be exposed to moisture, rain, sunlight, or dropped.
4. After reading, first press the button to turn off the high voltage, and the high voltage indicator goes out. Then set the function selector switch to the "ON" position to turn off the power. For capacitive loads, the residual charge on the test object should be discharged before disconnecting the test leads to avoid electric shock.
5. When measuring high insulation resistance values, a conductor guard ring should be placed on the surface between the two ends of the measured object, and this conductor guard ring should be connected to the guard terminal of the meter with a test lead to eliminate measurement errors caused by surface leakage current of the measured object and ensure accurate testing.
