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Guru
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CW / CCW Electric Motors

07/28/2009 3:08 PM

Is there a standard convention for electric motor rotation? In other words, when a rotation direction is specified as CW or CCW, are you viewing the motor from the shaft end or non-shaft end?

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Guru
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#1

Re: CW/CCW electric motors

07/28/2009 3:20 PM

Typically, in my experience, it's stated CW or CCW facing the shaft.

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Guru
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#2
In reply to #1

Re: CW/CCW electric motors

07/28/2009 3:51 PM

I'm not saying you're right or wrong, but I have seen it stated both ways.

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Guru
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#3
In reply to #2

Re: CW/CCW electric motors

07/28/2009 4:07 PM

I have seen it stated both ways also, but the vast majority of times it is stated, "facing shaft."

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Guru

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#6
In reply to #2

Re: CW/CCW electric motors

07/28/2009 11:32 PM

The standard is as viewed from drive end in India

Indian Standard IS 325 Annexure B (Information to be given at the stage of enquiry and placement of order)

Clause 13 states : "Direction of rotation Viewing from Drive End"

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Guru

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#4

Re: CW/CCW electric motors

07/28/2009 4:32 PM

It should be as viewed from the shaft. That's the standard way in the US. Europeans used to do it reverse, but I think they've all standardized now.

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#5

Re: CW / CCW Electric Motors

07/28/2009 8:08 PM

Usually, we will base on the motor driving shaft for the direction to specified as CW or CCW rotation as the driving shaft is that one that drive the load.

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#7

Re: CW / CCW Electric Motors

07/29/2009 1:39 AM

Normally the specification dictates this. IEC specification specifies from the shaft of the motor. Not too familiar with Nema specifications, so I'm not sure what they specify.

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#8

Re: CW / CCW Electric Motors

07/29/2009 7:16 AM

I don't normally revert to theology since Chris and Moose take a dim view, but I went to scripture for this. McMaster-Carr consistently says, "...CW as viewed from shaft end...", or "...CW as viewed from lead end..." Almost always, it's from shaft.

Now, the hard part is figuring out how to spec it when it has a shaft on both ends.

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Guru
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#9

Re: CW / CCW Electric Motors

07/29/2009 10:50 AM

Thank you all for your input. Shaft end it is.

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#10
In reply to #9

Re: CW / CCW Electric Motors

07/29/2009 11:17 AM

DC motors go's buy the outher end

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Guru
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#11
In reply to #10

Re: CW / CCW Electric Motors

07/29/2009 11:51 AM

It doesn't matter with a DC motor because their rotation is determined by how you connect it to the power source.

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Guru

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#12
In reply to #11

Re: CW / CCW Electric Motors

07/29/2009 12:33 PM

Same for most of the ACs too.

The direction of the motor is decided most of the time based on the cooling air flow rather than anything else.

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#13
In reply to #11

Re: CW / CCW Electric Motors

08/13/2009 2:58 PM

Not necessarilty true. You can reverse the direction of a DC motor without accessing the feed connections by reversing the armature leads.

As to direction, I have always seen it to be referended from the load end.

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#14

Re: CW / CCW Electric Motors

11/26/2010 11:51 AM

it differs from make to make

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