Motor RPM Sizing
Motor RPM Sizing
(OP)
Qusetion, if a OEM motor is size at 208/230v 1050 rpm. Could you replace it with the same voltage but a 1075 rpm motor. How much is the different between cfm with a 1050 verses a 1075 rpm? Thanks
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RE: Motor RPM Sizing
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RE: Motor RPM Sizing
If you were to remove the load completely off of both motors there would be very little difference, if any, in RPM between the two.
So you can replace the motor with the 1075. You just may need to consider, as Pete pointed out, the new CFM output of the blower and possibly (I doubt if you will need to) restrict the output a bit!
RE: Motor RPM Sizing
RE: Motor RPM Sizing
There are additional factors or parameters needed for the correct answer, namely:
1. NEMA Design Code Letter, either A, B, C, D, or E often appearing on the motor nameplate
2. The motor loading, e.g. 80%
3. Motor manufacturing tolerance since the 1075rpm/1050rpm=1.0238 suggesting 2.38% increase only, which is a very small increase. I.e. the motor marked with 1075rpm may actually run slower than the motor with 1050rpm depending on the motor manufacturing tolerance. Also, meters often have a 5% accuracy, 2% accuracy, 1% accuracy, etc.
RE: Motor RPM Sizing
RE: Motor RPM Sizing
Controls the speed (vfd) or switches the motor on/off based on pressure?
I think Steve has a lot of experience with small motors and I believe him most likely the 2.5% change in speed will not cause any problems.
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Eng-tips forums: The best place on the web for engineering discussions.
RE: Motor RPM Sizing
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Eng-tips forums: The best place on the web for engineering discussions.
RE: Motor RPM Sizing