How clos is inrush point to the curve
How clos is inrush point to the curve
(OP)
Attached is a result of coordination study of a fault fiter fuse( S&C ) and low voltage ckb. What margine need to exist between the inrush point and the fuse curve to safely order the fuses?






RE: How clos is inrush point to the curve
I assume that the point is draw at 12x nominal current of the transformer. This is a conservative assumption, since every transformer is different and the utility impedance will limit the inrush current.
So if the curve doesn't touch the point, this is probably good. I saw a transformer with an instantaneous at 8x is nominal current, but it work fine, so why fix it.
The 12x point is to be sure, when the coordination is tight, I assume that it is less than that.
RE: How clos is inrush point to the curve
How would I be certain to tell the customer to change his existing fuse to fault fiter, spend alot of money and then , it trips for inrush.....
even if we measure the inrush..it might vary right?
RE: How clos is inrush point to the curve