The megohmmeter is used to measure the insulation resistance of insulating materials, electrical products, and various components; when matched with a constant temperature water bath, it can also measure the insulation resistance of plastic wires and cables (without shielding layer) at different temperatures. This instrument has measurement accuracy High, stable performance, simple operation, short circuit at the input end, etc.

The following various preparations need to be made before megger measurement:

(1) Before measurement, the power supply of the equipment under test must be cut off and short-circuited to ground. Never allow the equipment to be charged for measurement to ensure the safety of people and equipment.

(2) For equipment that may induce high voltage, this possibility must be eliminated before measurement.

(3) The surface of the measured object should be clean to reduce the contact resistance to ensure the accuracy of the measurement result.

(4) Before measuring, check whether the megohmmeter is in normal working condition, mainly check its "0" and "∞" points. That is, shake the handle to make the motor reach the rated speed. The megohmmeter should be at the "0" position when it is short-circuited, and at the "∞" position when it is open.

(5) When using the megohmmeter, it should be placed in a stable and firm place, and far away from large external current conductors and external magnetic fields.

After the above preparations are done, the measurement can be carried out. When measuring, pay attention to the correct wiring of the megohmmeter, otherwise it will cause unnecessary errors or even errors.