ELECTRICAL MOTORS AND CONTROLS
ELECTRICAL MOTORS AND CONTROLS
(OP)
I HAVE A WESTING HOUSE CONTROL CENETR WITH 100A ADUSTABLE INSANTANEOUS TRIP BREAKER INSTALLED FEEDING A THIRTY H.P. THREE PHASE 480V INDUCTION TYPE B ENERGY EFFIENT MOTOR NEED TO CHANGE TO A FIFTY H.P. OF THE SAME TYPE WHAT SIZE BREAKER DO I NEED ?





RE: ELECTRICAL MOTORS AND CONTROLS
The feeder is probably too small, however.
RE: ELECTRICAL MOTORS AND CONTROLS
This is just a recommendation, do your own calcs and compare them. See NEC Table 430.52 for example.
Regards
RE: ELECTRICAL MOTORS AND CONTROLS
RE: ELECTRICAL MOTORS AND CONTROLS
These mag-only breakers used in motor starters are available with different instantaneous ranges for the same nominal breaker size.
To be absolutely safe, the instantaneous range should be adjustable up to about 1500 A.
RE: ELECTRICAL MOTORS AND CONTROLS
The max. inst. setting = 11 x 65 =715A
You are allowed to go up to 17 x 65 =1100A if the 715A is proven to be too small for the starting current.
A 100A Square D Mag. only CB will work nicely. I assume your brand is similar, you'll have to verify that.
RE: ELECTRICAL MOTORS AND CONTROLS
"Whenever you are asked if you can do a job, tell them, certainly I can! Then get busy and find out how to do it." Theodore Roosevelt.