Home › Electrical Engineering Forum › General Discussion › Thermal O/L Relay setting › Re: Thermal O/L Relay setting
2011/05/07 at 8:38 pm
#12071
erickench
Participant
NEC 430.32 gives the rules for sizing motor overloads. You must either determine the service factor which should be on the nameplate or determine the marked temperature rise also on the nameplate.
Motors with a marked service factor 1.15 or greater 125%
Motors with a marked temperature rise 40'C or less 125%
All other motors 115%