Regarding the issue of induced electricity in the electrical control box
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Dear fellow sailors, I’ve run into a problem and would like to ask the experts here for any suggestions or solutions. Thank you in advance. It’s like this: our company sold a piece of equipment overseas. The voltage specified at the time was 3-phase AC440V/50HZ for the main circuit, and single-phase AC250V for the secondary circuit (three-phase five-wire system). At the customer’s site, the equipment was powered by a generator, which could provide only 3 live wires at 440V, with no neutral or ground wires. So the customer obtained an AC230V supply from another source for the secondary circuit (the relay coils and buttons can operate with a voltage range of 220V to 250V). The equipment managed to start the motor and functioned, but when it was ready to operate properly, all the start/stop indicator lights as well as the lights on the intermediate relays came on. Does anyone know what’s causing this? Is there any solution? Thank you
It is caused by induced voltage; this can be mitigated by using shielded cables, spare conductors, and shield grounding to reduce the induced voltage
The equipment manages to start the motor and it functions, but when it is ready to operate properly, all the start and stop indicator lights as well as the light of the intermediate relay come on. Does the motor here refer to a generator? What exactly is the difference between running and starting? All the start and stop indicator lights are on. Are the brightness levels of these lights consistent? All the lights of the intermediate relays are also on; does that mean all the relays have activated? It isn’t described clearly, so it’s hard for others to answer.
It’s the same in my factory too; everything is lit, but upon closer inspection, the brightness levels vary
This post was last edited by chb1534 on 2018-5-29 at 13:26. Based on your description, since there are no neutral and ground wires, I assume the grounding of this box isn’t properly done; generally speaking, as long as the grounding is proper, this phenomenon can basically be eliminated. Our company has encountered many similar situations during the debugging of products before they leave the factory, but by grounding the enclosure, this phenomenon of induced electricity is basically eliminated.
The grounding issue is that the light isn’t very bright, and there is an induced voltage of over 100 V. Use a wire to connect the generator housing to the equipment housing