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#77326 05/20/01 09:50 PM
Joined: Oct 2000
Posts: 5,392
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sparky Offline OP
Member
I am seeing many intermittent motors of various size over 1 hp without overload protection. I also see many 220V 1ph intermittent that disconnect only one hot leg.
Many of these have the maker's instructions pointing out 430-33.
My gut says something is fishy.

any input appreciated... [Linked Image]

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#77327 05/21/01 05:18 AM
Joined: Dec 2000
Posts: 38
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Sparky what application do you see motors controlled by only opening one grounded conductor? That sounds a little frightening . Who services these motors?art 430-103 says open all ungrounded supply conductors.

#77328 05/21/01 06:31 AM
Joined: Oct 2000
Posts: 5,392
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sparky Offline OP
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i recently 'got into it' with tec support on a motor that serves a car lift.
there was only a momentary contact switch to serve one leg of a 220v 1 ph motor.

as 430-33 allows them to basically get away without overload protection , thus starter, there is no disco for the motor, except the breaker.

to me, this is an example of manufacturer's using the NEC to weasle around the expense of doing things right.

[Linked Image]

#77329 05/21/01 08:44 AM
Joined: Nov 2000
Posts: 2,148
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The motor controller is only required to open enough conducotrs to stop the current flow. On a single phase motor this would be 1 conductor, and on a 3 phase it would be 2 conductors. See 430-84.
430-103 applies to the motor disconnect, NOT the condroller, and is required to open all of the ungrounded supply conductors.

Sparky,
Your car lift installation requires a disconenct loacted in sight from the controller (430-102). If the momentary switch directly operates the motor, it is the controller. If the momentary switch operates a contactor, the contactor is the controller.

Don(resqcapt19)


Don(resqcapt19)

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