Digital multimeter to measure whether the wire leakage method is working.
With a multimeter to measure the wire to the ground whether leakage, there are two methods: one is charged measurement, multimeter adjusted to the AC file, in the case of equipment energised to measure the voltage between the equipment shell and the ground, the voltage in the dozens of volts is generally induced electricity, more than one hundred volts or more can be sure that the equipment has a leakage. This detection method is generally not recommended, the second method is to disconnect the power supply, measure the insulation resistance of the firewire and zero line firewire and ground, measured with a multimeter is not too accurate, accurate should be used to another instrument shaking table. Measured with a multimeter, generally more serious leakage can be shown from the multimeter, the resistance value is generally in the hundreds of ohms to dozens of ohms.
Digital multimeter measurement method:
1, the multimeter adjusted to the AC file, in the case of equipment energised, measuring the voltage between the equipment shell and the ground (determined to be the ground), if the voltage range of dozens of volts or one hundred and ten volts, is that the induction power, if it is 220V or 380V, is that the leakage.
2, the multimeter adjusted to the AC file, in the case of equipment power, measuring equipment shell and zero line voltage, if the voltage range of tens of volts or one hundred and ten volts, it is induced electricity, if it is 220V or 380V, it is a leakage.
But strictly speaking, the measurement of line insulation resistance circuit whether leakage should use a shaking table, shaking table is equivalent to a 1000v or 500v generator, leakage current through the shaking table internal sampling resistance, on the resistor to produce a sampling voltage signal. Normally, a stable greater than 0.5 megohm is qualified.
Digital multimeter to measure whether the wire leakage method
The method is as follows:
1, the equipment will be de-energised, fully discharged, do a good job of safety measures and hanging tips, and then unlock the cable two-side terminals to be measured. Never allow equipment charged for measurement to ensure personal and equipment safety.
2, before the measurement to check whether the megohmmeter is in normal working condition, mainly check its "0" and "∞" two points. That is, shake the handle, so that the motor to reach the rated speed, megohmmeter in the short-circuit should be pointed at the "0" position, open-circuit should be in the "∞" position.
3, L "line end knob connected to the measured equipment conductor," E "ground end knob grounded equipment shell," G "shield end connected to the insulated part of the equipment being tested, turn the table to 120 rpm average speed rotation, if the reading is stable Greater than 0.5 megohm is qualified, and vice versa, the insulation is not enough, there is the possibility of leakage.
