Before measuring, first perform an open circuit and short circuit test on the megger to check whether the megger is in good condition. If both connecting wires are open and the handle is shaken, the pointer should point to ∞. (infinity). At this time, if both connecting wires are connected, momentarily short the wires and the pointer should point to 0. At this time, the meter is in good condition.
Connect the L terminal (line end) of the megger to the water pump motor terminal box and connect the E terminal (ground end) of the megger to the water pump motor housing. water.
When measuring, press the meter housing with one hand (to prevent the meter from vibrating). When the needle indicates 0, stop shaking immediately to avoid burning the meter;
When measuring, place the meter in a horizontal position and turn the generator crank at a speed of about 120revolutions per minute
The reading after the pointer is basically stable after shaking for about 1 minute, this is the insulation resistance value of the motor.
Principles of selection of megohmmeters: ?
(1) Selection of rated voltage level. Generally speaking, for equipment with a voltage rating below 500 V, a 500 V or 1000 V megger should be used; For equipment with a rated voltage above 500V, a 1000V~2500V megometer should be used. For equipment with a voltage rating greater than 10 KV, a 2500 V megger should be used.
(2) Resistance range selection. There are two small black dots on the scale of the megger dial, and the area between the small black dots is the precise measurement area. Therefore, when selecting a table, the insulation resistance value of the equipment under test should be within the measurement areae specifies.