Breaker Instantanious Settings
Breaker Instantanious Settings
(OP)
Dear Friends,
I need to adjust instantaneous settings on a 600AMP magnetic breaker that feeds a 250KVA 600/208V transformer. This breaker only has instantaneous settings.
I don't have any background in this field and appreciate any feedback on this subject.
Thanks
I need to adjust instantaneous settings on a 600AMP magnetic breaker that feeds a 250KVA 600/208V transformer. This breaker only has instantaneous settings.
I don't have any background in this field and appreciate any feedback on this subject.
Thanks






RE: Breaker Instantanious Settings
JRaef.com
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: Breaker Instantanious Settings
RE: Breaker Instantanious Settings
RE: Breaker Instantanious Settings
And, as mentioned by others, why do you need to change the settings?
RE: Breaker Instantanious Settings
Two loads were fed from a single breaker,we are seperating the protection for each load.
We are in Canada.This is a new installation and I need to adjust the breaker settings.
RE: Breaker Instantanious Settings
"Turn the adjustments with a screwdriver."
RE: Breaker Instantanious Settings
Thanks for the reply.
Its a 600AMP thermal-magnetic breaker to protect a 250KVA 600V/208. What other information is missing?
RE: Breaker Instantanious Settings
RE: Breaker Instantanious Settings
Chiller and transformer were fed from a same breaker. Now, chiller will be on seperate 600AMP and Transformer on new 600AMP breaker.
RE: Breaker Instantanious Settings
Your 600A C/B typically would have an Inst range of 5x to 10x the rating (3000A - 6000A), so any setting shouldn't cause a nuisance trip, though it will apparently allow a 250% overload of the transformer. This may or may not be acceptable for your application.
The proper way to do this, though, is to plot the C/B curve and the transformer damage curve to verify protection.
RE: Breaker Instantanious Settings
The reason I ask is that if it is 3 phase 225kVA, the FLA will actually be around 217A. If it is 3 phase and 250kVA then it is a custom wound transformer, making DanDel's comment on attaining the damage curve even more important.
If it is a 1 phase 250kVA, the primary current will be around 417A, which makes a difference in your magnetic settings (as far as the amp rating, not the percentages).
JRaef.com
Eng-Tips: Help for your job, not for your homework Read FAQ731-376