NEC definitions
NEC definitions
(OP)
Hi, I am trying to get my head clear around the following definitions. Can anyone specify the differences between the following devices to control motor in LV assemblies:
Motor controller,
Motor combination starter
Combination motor controller
self protected combination controller
Full voltage none reverse (FVNR) motor starter
Full voltage Contactor (FVC)
Which ones provide short circuit, overload and ground fault protection all in one unit, which ones required an additional Circuit breaker or fuse on the input, etc.
I understand these definitions change from country to country, so i want the North american definitions.
Regards,
Motor controller,
Motor combination starter
Combination motor controller
self protected combination controller
Full voltage none reverse (FVNR) motor starter
Full voltage Contactor (FVC)
Which ones provide short circuit, overload and ground fault protection all in one unit, which ones required an additional Circuit breaker or fuse on the input, etc.
I understand these definitions change from country to country, so i want the North american definitions.
Regards,





RE: NEC definitions
A starter is a contactor (or manual switch) plus overload protection.
Controller is a generic NEC term used for any type of motor control. A starter is a controller, but not all controllers are starters.
"Full voltage" is just referring to the starting method.
None of these provide ground fault protection unless it is specified to be provided.
RE: NEC definitions
"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
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RE: NEC definitions
RE: NEC definitions
"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies
RE: NEC definitions
Motor Controller: Any device that can start and stop a motor (this is from the NEC). ---From this I get i can use an instantaneous, or inverse time, circuit breaker, or a switch, but can not use a fuse.Correct?
Motor Starter: A controller with overload protection. ---- From this a motor starter is a inverse time CB, or a switch (contactor) with a time delay fuse, or a contactor with an overload protection. Correct?
Combination Motor Starter: Is a motor starter that includes Short circuit protection---I can use an inverse time CB, a switch with a time delay fuse, or a contactor with an overload and a fuse. Or by definition all this needs to be include in one big unit ?, so the only equipment that will fullfill the definition will be the CB with time delay? If all this came in one big unit isnt this a self protected controller?.
From my experience all this devices goes inside the MCC, so if i install a fuse, a contactor and an overload protection inside the module, can i call the module a Motor combination starter, FVNR for example?, but if i take the overload protection away i can call the module a FVC (Full voltage contactor) combination starter?.
Regards,
RE: NEC definitions
Starters do not have to be in an MCC - they can be separately mounted in their own enclosure or part of a control panel.
A controller does not have to be a circuit breaker. A contactor is a motor controller per NEC.
RE: NEC definitions
"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies