Discussion on the problem of induced electricity
Thread Content
During a fault repair on the electrical instrumentation panel in our facility (which monitors the status of pumps and motors, as well as contains relay cabinets for start/stop signals), it was accidentally discovered that the dry contact signals indicating the status of the electrical motors were mixed in with the 24V power supply of those relays； When disconnecting the connections at both ends of the cable ； Each of the two wires has a voltage of 170V with respect to ground, while there is no voltage between the two wires ； When the instrument side is connected back, this voltage cannot be measured with respect to ground, and moreover, it has no impact during actual operation! I asked the electrical technician, and they said it’s normal: Where does this voltage come from? Is there really no impact? How to eliminate it?
I didn’t understand what ‘dig’ means. . . . . . . . .
Induced electromotive force is a common phenomenon, as signals from high-voltage electrical equipment generally exhibit this. So generally, such signals use 220VAC for voltage acquisition. Regarding the acquisition (measurement) voltage used for detecting switch signals, 24VDC is generally employed, but for high-voltage electrical switches, 220VAC must be used; this is something that needs to be taken into account during the design phase.
It’s the cable coming from the electrical supply that has an induced voltage of around 170V
It’s about detecting voltage; digital signals aren’t fed into the current either, so how is it detected?
Using shielded cable with single-sided grounding can solve this problem