Auto change Over Scheme

What do you want? Circuit/application.

You have already explained the function.

For MCC- since the rating is only 400 Amps, you can consider motorised MCCB with suitable electrical and mechanical interlock.Since there are two sources and seperate control supply,you should have two nos under voltage relays located in each of the incoming source

Alternatively you can consider two 400 A contactors with Switch disconnectors.the 400A contactors can be electrically and mechanically interlocked.

same logic will be applicable for 100 Amps DB

Thank you dear ramvinod,

The already case was Medium voltage and with bus-coupler.

I think the contactor solution is cheaper than motorized MCCB. But 400 A contactors with Switch disconnectors combination can withstand 50kA/1S short circuit current? However a simple circuit will be useful for both cases.

Check with Vacuum Contactor sckt level.

The question need to be clearly stated.Any how wth what I have understood i think u can use contactors to change over.You will need a monitoring relay which will ensure change over and control sequence.RTU ATS panels are available these days.