How to size frequency converter

[Dbronx]

I have a 3 phase 208 volt 400 amp load to feed. The primary is 400 volts 200 amps, what size frequency is converter needed?

 

[ActionDave]

Some more information is needed. From what I gather reading your post it sounds like you are needing a transformer.

What are you hooking up?

 

[Jraef]

I have a 3 phase 208 volt 400 amp load to feed. The primary is 400 volts 200 amps, what size frequency is converter needed?

Chances are that at 400V, it is 50Hz, 208V would be 60Hz. So yes, you would theoretically need a frequency converter, then a transformer. But first, you will need to find a bigger source of power. You need 400A at 208V, that is 83.2 kVA. You have a source capable of delivering 400V x 200A = 80kVA, you are a little short, especially when you factor in the losses in the transformer and whatever you use to convert the frequency. You likely really only have about 60-65 kVA available to use ay 208V 60Hz by the time you get done. To get to where you have the full 83.2kVA, you will need to start out with a 400V 50Hz circuit capable of at least 250A, 300A would be safer.