Motor math question... Feeder Fuse. - 06/14/07 12:58 AM
I thought I had motors figured out. After some reviewing I'm missing something.
Anyone wanna help?
All conductors are THW 75*C terminations.
25hp, 25hp, 15hp, 5hp
208V three phase
w/ non-time-delay fuse.
What is the Feeder fuse size?
This is how I think the problem is done but Its not Im missing something.
Take the largest motor FLC @ 125% = 93.5A
Get the fuse size for 93.5A = 100A
Now add that 100A with the FLC of the remianing motors.
100
74.8
46.2
+ 16.7
= 237.7A
Round down and the Feeder fuse should be 225A
Thats wrong, apparently the answer is 350A Feeder Fuse.
Help me out here I'm missing something. Thanks.
Anyone wanna help?
All conductors are THW 75*C terminations.
25hp, 25hp, 15hp, 5hp
208V three phase
w/ non-time-delay fuse.
What is the Feeder fuse size?
This is how I think the problem is done but Its not Im missing something.
Take the largest motor FLC @ 125% = 93.5A
Get the fuse size for 93.5A = 100A
Now add that 100A with the FLC of the remianing motors.
100
74.8
46.2
+ 16.7
= 237.7A
Round down and the Feeder fuse should be 225A
Thats wrong, apparently the answer is 350A Feeder Fuse.
Help me out here I'm missing something. Thanks.