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#163127 - 05/01/07 03:17 PM How to phase a motor
bwise121 Offline
Member

Registered: 09/11/03
Posts: 113
Loc: Sacramento, CA USA
I've been asked to phase a 3-phase motor. I'm not sure if this is normally the electrician's job or the HVAC's. What type of meter do I need and what is the process?

Thanks,
Byron

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#163131 - 05/01/07 05:25 PM Re: How to phase a motor [Re: bwise121]
RobbieD Offline
Member

Registered: 02/23/03
Posts: 238
Loc: Canada
Question-

Do you just have to do a rotation test?

or

Do you have this 3 phase motor and all of the winding connections are all apart and you need to connect them up?

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#163132 - 05/01/07 05:39 PM Re: How to phase a motor [Re: RobbieD]
bwise121 Offline
Member

Registered: 09/11/03
Posts: 113
Loc: Sacramento, CA USA
Rotation test only.

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#163133 - 05/01/07 05:56 PM Re: How to phase a motor [Re: bwise121]
RobbieD Offline
Member

Registered: 02/23/03
Posts: 238
Loc: Canada
If its for a piece of equipment that won't mind it going the wrong way for a short time then I would just do the 50/50 test. If you find it going the wrong direction just change it. No meters required just eyes.


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#163134 - 05/01/07 06:16 PM Re: How to phase a motor [Re: RobbieD]
bwise121 Offline
Member

Registered: 09/11/03
Posts: 113
Loc: Sacramento, CA USA
But... if I want to meter it and have it going the right way to begin with?


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#163136 - 05/01/07 06:34 PM Re: How to phase a motor [Re: bwise121]
togol Offline
Member

Registered: 09/15/05
Posts: 426
Loc: NW In. USA
there are two types of phase rotation meters one requires line voltage to operate and the other is self-powered to check motors that are unwired...or going back into service

you use the powered type by connecting the three meter leads to your source voltage usually at the equipments last termination such as a starter or disconnect to verify your incoming voltage...and if you have an arrow on the motor..you then connect the motor leads 1,2,3, for the correct rotation..which as I recall is CCW opposite the shaft end

if you want to check a dead motor and can turn the shaft, use the self-powered type ...again connecting the meter leads to the motor leads and turn the shaft

several are available from Fluke, AEMC, Knopp,....
and Ideal makes a multimeter that you can use


_________________________
Tom

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#163137 - 05/01/07 06:48 PM Re: How to phase a motor [Re: bwise121]
togol Offline
Member

Registered: 09/15/05
Posts: 426
Loc: NW In. USA
BTW, in my opinion the Fluke is overpriced at almost $200.00

the AEMC PMR-2 is the most economical, <<<<I own this one

while the Knopp is the most rugged and has been around a long time
_________________________
Tom

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#163138 - 05/01/07 07:47 PM Re: How to phase a motor [Re: bwise121]
togol Offline
Member

Registered: 09/15/05
Posts: 426
Loc: NW In. USA
and there are several to choose from right here at the ECN Store
http://www.electrical-contractor.net/The_Store/EX/480300_303.htm


Edited by togol (05/01/07 07:48 PM)
Edit Reason: spelling
_________________________
Tom

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