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Thread: Motor Branch Circuit Protection

  1. #11
    Join Date
    Jul 2006
    Location
    San Francisco Bay Area, CA, USA
    Posts
    8,121
    That particular toggle switch does NOT have an OL heater in it. You CAN get ones that have it, but that one does not.

    All motors must have protection from overload. SOME small (typically fractional HP) motors come with built-in thermal overload protection so the control device, such as that toggle switch, do not need to provide it externally. IF the motor has thermal overload protection, it MUST state it on the nameplate, usually using the words “Thermally Protected”, or sometimes abbreviated as just “TP”, or words / abbreviations to that effect. It that is not CLEARLY designated or readable on the motor nameplate, you must assume it needs external.

    On small things like the aforementioned clock motor, it will often say it is “impedance protected”, which means it can be totally stalled and not be overloaded.
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  2. #12
    Join Date
    Sep 2012
    Location
    NJ
    Posts
    2,232
    Quote Originally Posted by Jraef View Post
    That particular toggle switch does NOT have an OL heater in it. You CAN get ones that have it, but that one does not.

    All motors must have protection from overload. SOME small (typically fractional HP) motors come with built-in thermal overload protection so the control device, such as that toggle switch, do not need to provide it externally. IF the motor has thermal overload protection, it MUST state it on the nameplate, usually using the words “Thermally Protected”, or sometimes abbreviated as just “TP”, or words / abbreviations to that effect. It that is not CLEARLY designated or readable on the motor nameplate, you must assume it needs external.

    On small things like the aforementioned clock motor, it will often say it is “impedance protected”, which means it can be totally stalled and not be overloaded.
    Thanks.

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