Motor Rotation CW vs CCW
Motor Rotation CW vs CCW
(OP)
We have a 400 HP, ODP, 4160 volt, 3 phase motor that was built by the manufacture to run CCW. We have a different pump we would like to couple this CCW motor to. Problem is the different pump needs a clockwise rotating motor. Will most likely run louder. Not an issue. Will cooling be an issue with this ODP? Will the internal cooling fins not function correctly runing CW? My main concern is if this motor running CW will have close to the same torque output as it does running CCW??? Don't want to risk damaging this expensive motor. Any comments or previous threads would be appreciated. Searched previous threads for a few hours. No luck.





RE: Motor Rotation CW vs CCW
If it is an ODP, there may be a chance that you can peak through the inlet air opening (with motor secured) to get a look at the rotor fan. Or else boroscope. Or else contact oem. Or else, do you feel lucky?
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(2B)+(2B)' ?
RE: Motor Rotation CW vs CCW
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(2B)+(2B)' ?
RE: Motor Rotation CW vs CCW
But, if the motor has unidirectional fans, it will not be cooled properly with the fans running backwards.
The best course of action is to inspect the fans. You may be able to interchange the DE and NDE fans.
Bill
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"Why not the best?"
Jimmy Carter
RE: Motor Rotation CW vs CCW
I have come across (quite a few times) where the internal directional fans are reversable simple by turning them around.
Thanks.
RE: Motor Rotation CW vs CCW
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
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RE: Motor Rotation CW vs CCW
RE: Motor Rotation CW vs CCW
And no, the motor torque is not affected in any way change in direction.
Muthu
www.edison.co.in
RE: Motor Rotation CW vs CCW
RE: Motor Rotation CW vs CCW
Interesting to use the arrow as an indicator whether the fan is unidirectional. I haven't heard of that, but there may be something to it.
At our plant, I think all large motors have arrows, whether directional or not. I'm not sure if we added them ourselves, or if it was part of our purchase spec. I realize of course motors without unidirectional cooling don't care, but I thought maybe it coordinates with a connection labelplate.
I see that NEMA MG-1 requires arrow for unidirectional fan, but they don't prohibit it for non-unidirectional.
I'm still a little unsure what to make of all that. I know at our plant, presence of an arrow wouldn't prove anything one way or another.
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I don't think external fans is a good option. It is not likely it will create the correct internal cooling pattern.
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(2B)+(2B)' ?
RE: Motor Rotation CW vs CCW
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(2B)+(2B)' ?
RE: Motor Rotation CW vs CCW
"I see that NEMA MG-1 requires arrow for unidirectional fan, but they don't prohibit it for non-unidirectional."
When a motor is sold as a package in an equipment like compressor or pump, then the motor (with bidirectional fan) will be stamped for direction by motor OEM / equipment OEM / assembler.
All motors with unidirectional cooling fans are required to have the direction stamped.
Muthu
www.edison.co.in
RE: Motor Rotation CW vs CCW
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies
RE: Motor Rotation CW vs CCW
Thanks
RE: Motor Rotation CW vs CCW
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(2B)+(2B)' ?
RE: Motor Rotation CW vs CCW
Bidirectional fans are of the centrifugal type with a fan blade angle of 90 degrees. Such fans are not very efficient as far as the power is concerned they absorb from the shaft. Curved fan blades are more efficient and axial fans are most suitable for large output motors (and generators). Such motors, however, have to be directional ones, with the sense of rotation marked somewhere.
Wolf
www.hydropower-consult.com
RE: Motor Rotation CW vs CCW