Safety precautions for the use of megohmmeter:

(1) Because the working voltage of electrical appliances and the requirements for its insulation resistance are different, when measuring the insulation performance of different electrical appliances, a megohmmeter of the corresponding specifications should be used.

(2) Generally, there are 3 terminals on the megohmmeter, marked with (E) grounding, (L) circuit, (G) guard ring marks near the terminals, and (E), (L) on the terminals Connect the test rods respectively. When using a megohmmeter, perform an open circuit and short circuit test on the megohmmeter to check whether the megohmmeter is in good condition. When the two test rods are open, shake the generator handle and the pointer should point to the infinity of the surface scale; when the two test rods are short-circuited, shake the handle and the pointer should point to 0Ω, otherwise the megohmmeter will malfunction.

(3) When measuring the insulation resistance of the electrical circuit to the earth, the circuit under test is connected to the (L) test rod and the earth to the (E) test rod. When measuring the insulation resistance of electrical equipment such as motors and transformers, (L) connect the test rod to the wire of the motor and transformer coil windings, and (E) connect the test rod to the metal shell of the motor and transformer.

(4) When measuring the insulation resistance between the cable core and the cable shell, in addition to connecting the (L) and (E) test rods to the cable core and the cable shell respectively, it is also necessary to connect the insulation between the cable shell cores to the The protective ring (G) of Eurometer is attached to the terminal to eliminate errors caused by measurement. When measuring the insulation resistance between the core wires of the cable, connect the (L) and (E) test rods to the two core wires respectively, and connect the protective ring terminal (G) to any insulation of the core wire to be tested .

(5) When using a megohmmeter to measure the insulation resistance of electrical equipment, the power supply of the electrical equipment must be cut off first to ensure the equipment and personal safety.

(6) Turn the handle of the megohmmeter to maintain a certain speed, requiring 120 revolutions per minute, at least not less than 90 revolutions, and at most not more than 150 revolutions.

(7) When measuring the insulation resistance of electrical appliances, if the pointer of the megohmmeter has pointed to 0Ω, you can no longer shake the handle at this time to avoid damage to the coil in the meter.