What Happens if 2K2 & 2K3 Close Simultaneously?

[kenneth edmiston]

TL;DR

What happens when run and shorting contactors are closed in at the same time.

Can someone give me some insight into what would happen at the motor terminals and on the line if 2K2 (run Contactor) and 2K3 (auto xfmr wye contactor) were to close simultaneously. There are interlocks to prevent this, but I would like to know out of curiosity. My theory is that you would have reduced voltage and increase current at motor due to voltage drop and load torque demand, and a circulating current in the auto-xmfr.

thanks

 

[Tom.G]

Potentially a big BANG as the relay contacts vaporize.
But that's why there are fuses in the supply lines.

If you try the experiment be sure to have something substantial between it and you, a concrete wall perhaps. If you must watch it, use a video camera that you are willing to replace.

Cheers,
Tom