SparkyRules
Member
- Location
- United States
I have a 300HP (480V 3Ph) motor that table 430.250 tells me has a FLA of 361A and a start up (LR) per 430.251(B) of 2200A. What is the best way to reduce this start up current, VFD? Any other suggestions? :? And how much can this LR- amps be reduced? (as in the smallest size fuse that would be expected to hold after said starting current IS reduced)? Also per 430.6 the next standard fuse size is 2500A but table 430.52 says a 175% TD fuse will hold the start up current ( 2200 amps) Anyone have experience to know a dual element fuse at 700A will hold this motor? (361X 175=631.75A or 700A next standard size.). as I read 430.52(B)(1) exp does allow us to round up to the next standard size. Also am I correct that is the 700a does not hold then per exp 2 would be able to increase to an 800A TD fuse, using the same fuse holder. I mean really how expensive can it be if I get this wrong??? (Yikes)