Do any motors under 1hp require overload protection or could I just put it on a hp rated switch fed by a breaker and be ok? Next question I see many exhaust fans in Industrial plants that are normally fed by a breaker and then a snap switch at the fan itself do the snap switches have to have integral overloads for that to be ok?
Motors Under 1hp and Overload selection
- Thread starter kjroller
- Start date
ptonsparky
Tom
- Occupation
- EC - retired
Some of the snap switches do have overloads in them. Some motors may have overloads on them. The red button on the peckerhead. Sometimes the CB is adequate depending on size etc. See 430.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Yes, IMO somewhat better protection than overloads that only respond to current levels. Bad bearing in a motor generating heat still heats up windings but may or may not increase current enough to trip current overload methods as soon as embedded thermal device in the motor.
They usually are not rated to carry motor current except maybe on some fractional HP motors and would need to interrupt a control circuit instead of directly interrupting motor current.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
They are usually called manual motor starters in product catalogs, and are more common from Square D, Siemens, Allen Bradley, etc. more so than from Leviton, or Legrand. I don't know about Eaton, they have acquired many companies in past 25 -30 years and may have a line that was once under some other name, thinking what once was cooper devices could have had some of those. Hubbell maybe has them as well as standard common wiring devices?