Monorail System Powered by Generated --> 3-Phase Motors Started Arcing!!!

[quark555]

Hi,
I really need help to find out what happned ... At work we had power shutdown, and we had to use a generator to get the systems running. (One of the systems is a monorail system, (3-phase bus bar, with 3-phase motors being fed and running).

After running the generator, and wiating for some time to have everything settled down with the generator, upon running the monorail system, arcing ang sparking was noticed , even one busbar section got completely burned!!!.

I couldn't find any explanation for what had happened.... Waiting for your help plz..

 

[Diver300]

You haven't told us much information about the size of the generator, the rating of the monorail system etc, so I'm having to guess what the system is like.

The voltage regulation of a generator will be worse than the mains. There could also be a big problem with inductance and load dump. That means when the monorail motors stop, there could be a voltage spike from the inductance and a voltage surge as the voltage regulator in the alternator responds to the reduced load.

A spike is excessive voltage for a few µs. It could be thousands of volts.

A surge is excessive voltage for a few tenths of a second. It could be twice the normal voltage.

The problem is worse if you have nothing else connected to the generator.

The excessive voltage could cause the insulation to break down on the bus-bars, which could cause the sparking. If there is any dirt around the bus-bars, that would make the insulation less effective.

 

[Willbe]

Be careful
https://en.wikipedia.org/wiki/Arc_Flash

 

[quark555]

Thank you all for your replies... Regarding being dirty, actually we are having a problem of carbon accumulation.. (we are removing it from time to time, but we still have accumulation there).
But we never faced any spikes when using normal power.. (not the generator).