- #1
bachir1994
- 18
- 2
HelloLast week I was confronted with a situation where an industrial equipment, with a large equipotential mass (metal casing) that was not grounded, had a ground tension, measured with Fluke, of 382 vac. I put a 220 Vac bulb and nothing happens, the bulb remains off and is not burned out.
By measuring the voltage with the lamp as a charge it is a few millivolts. I even touch the carcass without feeling anything.
My interpretation is:
The voltage measured with the impedance of the fluke (Zfluke) >>> 20 M Ohm which is surely much higher than the internal impedance of the generator that is seen between the ground and the carcass of the equipment (E generator, Z generator), gives a high voltage (Vfluke) (voltage divider).
As soon as a 100 watt bulb is placed with an impedance close to 500 ohm (Z bulb), this impedance is considerably less than the internal impedance of the generator seen between the ground and the carcass of the equipment, which makes That the voltage at the voltage divisor point drops to the millivolt range.Thank you
By measuring the voltage with the lamp as a charge it is a few millivolts. I even touch the carcass without feeling anything.
My interpretation is:
The voltage measured with the impedance of the fluke (Zfluke) >>> 20 M Ohm which is surely much higher than the internal impedance of the generator that is seen between the ground and the carcass of the equipment (E generator, Z generator), gives a high voltage (Vfluke) (voltage divider).
As soon as a 100 watt bulb is placed with an impedance close to 500 ohm (Z bulb), this impedance is considerably less than the internal impedance of the generator seen between the ground and the carcass of the equipment, which makes That the voltage at the voltage divisor point drops to the millivolt range.Thank you