How to use the ground resistance test megger

　　How to use the ground resistance test megger

　　1. The instrument terminal wiring should be correct.

　　2. Adjust the mechanical zero position of the galvanometer after the instrument is placed horizontally.

　　3. Set the "magnification switch" to the maximum magnification. Gradually increase the crank speed to 150r/min. When the galvanometer pointer deflects in a certain direction, rotate the dial so that the galvanometer pointer points to the "0" point. At this time, the magnification gear on the dial is the measured resistance value.

　　4. If the dial reading is less than 1 and the balance has not been achieved, you can set the magnification switch to a smaller magnification until it is adjusted to complete balance.

　　5. If it is found that the instrument galvanometer pointer is shaking, the crank speed can be changed to eliminate the shaking.

　　6. If the sensitivity of the instrument galvanometer is too low, you can add water or salt water around the probe to moisten it.

　　Structural features of ground resistance test megohmmeter

　　The ground resistance test megger consists of a hand-operated generator, a current transformer, a slide resistor and a galvanometer. The entire mechanism is installed in a plastic case with a leather case outside for easy portability. Accessories include auxiliary probe wires, etc., which are packed in the accessory bag. Its working principle uses a relatively large reference voltage.

　　1. Benchmark range and accuracy (Table 1)

　　2. The auxiliary ground resistance affects the change amount. When the auxiliary ground resistance changes from 500Ω to the value specified in the table below, the allowable change amount should not exceed the value specified in the table (Table 2):

　　3. Other parameters are as follows (Table 3):

　　Precautions for ground resistance test megger

　　1. It is forbidden to measure when there is lightning or when the object under test is charged.

　　2. When carrying and using the instrument, you must handle it with care and avoid violent vibrations.