Motor starter contactor question

[1carwash1]

Looking to upgrade some older motor starters (contactors). Are contactors with overload protection (heaters) needed? Over the years I have seen some pumping plants with overload protection and others with contactors only, (i.e contactors with no built in overload protection).
Thanks

 

[mjwalsh]

Looking to upgrade some older motor starters (contactors). Are contactors with overload protection (heaters) needed? Over the years I have seen some pumping plants with overload protection and others with contactors only, (i.e contactors with no built in overload protection).
Thanks

I like the heavy duty contactors with the piggyback overload protection because you can get a more precise adjustable protection vs a set size of breaker or fuse size.

mike

 

[MEP001]

Something like this is what you want:

http://www.kleen-ritecorp.com/p-4119-allenbradley-motor-starter.aspx
http://www.kleen-ritecorp.com/p-4120-allenbradley-overload-protector-for-motor-starter.aspx

You may not need it for electrical code, but it's a really good idea. If for some reason you lose the third or high leg, your controls might still work but the motor will be fried.

The thermal overload does not cut the voltage to the motor like the old style contactor with heaters. IMO the best way to use one of these is to run the control voltage for the bay through the N/C circuit. That way if the overload trips the power to the bay is cut, and no one else loses money.