Max. Motor Size for MV MCC 4.16 400A Contactor

Also, you need to check the current transformer primary rating, so the CTs aren't overloaded during normal operation. Typically the starter will have R type motor starting fuses. You need to install the correct fuses so they coordinate with your overload relay protection. They are sized according to motor HP.

Some of the larger fuses are double barrel type, you need to confirm the clips will handle the correct fuse for the contactor.

This information is only available from the manufacturer of the equipment, which includes the testing of the starting assembly as designed to start the size motor.

i have no doubt that the contactor is capable of starting the motor across the line, but you must confirm that and the other details to successfully apply and operate the equipment.

Rough guesstimate on FLA of 4000V motors is 0.14A/HP.

^{"A 1.320 MW motor 230 A ,..."}

1320kW x .746 = 985HP x 0.14 = 138A, your numbers are off somewhere.

But can a 230A motor be controlled by a 400A contactor? Why not? 400 > 230 isn't it?

Assuming you are looking at Vacuum Contactors, a typical 400A VC is rated for 2750HP max at 4000V, so just over 2,000kW (2MW).

Air contactors may have slightly lower ratings because of arcing when attempting to interrupt current flow (not an issue with VCs), but I don't know of anyone using that any more and I don't have any data sheets for them.

Shouldn't that be 1320 kW ÷ 0.746 ≈ 1769 hp?

Yes... yes it should. I have made that same mistake twice today.

There needs to be a better emoticon for "shame"...

That sort of thing happens to me once in a while, too.
There is a blush emoticon:

Contactors generally have a HP rating on them.

A rule of thumb that is generally accepted is 1 KVA per hp.

This allows for starting loads,etc.

A link that will help is below.

https://www.geindustrial.com/techtuesday/dec/Technical_Tuesday_11-8-16_MV_MCC.pdf

Be careful.Be Very Careful.

I have seen the results of 4160V arcing in the form of the shadow of a rat copper-sprayed onto the enclosure wall.You could still see the surprise on his face.

Well,there were a few of pieces of singed fur,but that was it.

Remember the old adage:There are bold electricians,and there are old electricians,but there are no old,bold electricians"

Here is an additional link to information that you may find helpful in many areas.

https://www.geindustrial.com/publibrary

It depends on what the motor is driving and its starting current and starting duration.

This is not because of limitation on the contactor rating, instead, it is about the back up fuse.

Presuming the contactor comes with a 400A back up fuse, this may not be able to withstand two successive hot starts without blowing.

Please look into this aspect.