Determining field flash current values

[trev]

Hi All,

New member here so I hope that this post follows the rules of the forum. I did a quick search and didn't find what I was looking for so I thought I'd make a new post.

I'm sizing a station DC battery system and my preliminary thoughts have the exctation field flash the largest momentary current draw.

Is there a 'rule-of-thumb', IEEE reference, or a standard calculation I should be aware of to determine what a six second field flash current would be? I'd like to have something better than an estimate based off from other jobs.

Thanks in advance,
Trev

 

[rcwilson]

No standard that I am aware of. Usually that data comes from the generator supplier or the excitation equipment supplier.

I don't recall having much more than a 20 A, 125VDC circuit feeding the field flashing circuit, but most of our generators have seperately fed exciters that can provide field flashing from their 480V or 4.16 kV auxiliary power input. DC may only be used for control.