motor question

[Designer69]

We just got some Teco Westinghouse 25 horse 3 ph motors. I thought they would come with intergral overloads because I thought most new motors come with integral overloads these days. Guess I was wrong. No big deal just curious

 

[markstg]

motor integral overloads

motor integral overloads

We buy many Teco Westinghouse Motors, 460V, 3 phase, and None of them ever come with integral overloads (or internal thermal switch). The specification we purchase them under, of course, does not call for such to provided.

I have seen one or two come in with an internal thermal switch, but it is not wired up.

Motor overload protection is provided by the Overload Heaters mounted in the motor starter, sized for the Motor FLA and Service Factor.

 

[cpal]

Motor overload protection is provided by the Overload Heaters mounted in the motor starter, sized for the Motor FLA and Service Factor.

This is true but the Code recognizes integral protection also refer to 430.32.

 

[Jraef]

Integral protection is typically only found on small 120V single phase motors, usually 10A and under. The thermal device (called a "Kilxon") must be capable of switching the entire load, and all power poles, unlike a separate OL relay which turns off a contactor. So on something like a 25HP 3 phase motor, the "integral" device would still need to be the size of a 3 phase contactor, and where are you going to stuff it?