the physical difference between the 50Hz and 60Hz motor
the physical difference between the 50Hz and 60Hz motor
(OP)
guys, is there really a phsical difference in the 50Hz and 60Hz Motor ??? I always though that they are just rated differently, and what I meant by that is since they are made to be used in a country thats either 50 or 60 hz therefore they are factory test and rated at that frequency. thus if they are ever use on a different electrial system with different frequency, and thats when the motor perfermance doesn't match the spec. I am correct???





RE: the physical difference between the 50Hz and 60Hz motor
There are design differences due to the difference in inductive reactances and flux as a function of frequency.
David Castor
www.cvoes.com
RE: the physical difference between the 50Hz and 60Hz motor
Keith Cress
kcress - http://www.flaminsystems.com
RE: the physical difference between the 50Hz and 60Hz motor
The all other things being equal seems like something to watch our for, and I doubt there are many situations where all other things are exactly equal.
A related FAQ
http://www.eng-tips.com/faqs.cfm?fid=1224
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RE: the physical difference between the 50Hz and 60Hz motor
RE: the physical difference between the 50Hz and 60Hz motor
Muthu
www.edison.co.in
RE: the physical difference between the 50Hz and 60Hz motor
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RE: the physical difference between the 50Hz and 60Hz motor
Keith Cress
kcress - http://www.flaminsystems.com
RE: the physical difference between the 50Hz and 60Hz motor
Muthu
www.edison.co.in
RE: the physical difference between the 50Hz and 60Hz motor
Since the 60 Hz application called for that very same frame size anyway, is that a good solution or not? Or was it just coincidence?
Is this the same as a dual rated motor or is it just a pick where both frequencies happened to fall into a common frame whether that frame would have been picked for either of the individual 50 or 60 Hz applications?
rmw
RE: the physical difference between the 50Hz and 60Hz motor
If R and L scale proportionately, it would correspond then the product of R*L has to increase by 20% so each one increases by sqrt(1.2) ~ 1.1.
But there are a lot of things that can change (flux density, current density. Also frame can be oversized.
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RE: the physical difference between the 50Hz and 60Hz motor
I think that you got lucky and by coincidence, either rating would use the same frame size.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: the physical difference between the 50Hz and 60Hz motor
If we assume (as I did before) that the flux density and current density (amps per meter of circumference) are constant, then the total force is proportional to D*L, but the total torque is proportional to D^2 * L, which is roughly proportional to the volume or weight of the motor..
So if motor rated torque goes up by 20%, we may roughly expect the weight goes up by 20%, and the dimensions go up by (1.2)^0.333 ~ 1.063 (6% increase in dimensions).
Here is a link that provides a far better discussion than I could ever provide:
http://b
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RE: the physical difference between the 50Hz and 60Hz motor
We'll get approximately 20% more power from same core at 60 Hz than at 50 Hz.
This means that , for same power, the core at 50 Hz must be "greater" then at 60 Hz.
It's hard to say what it means "greater". Motor power depends on the internal diameter but also on the core-length. Manufacturer can modify one of these measures or both. Also, it is often the case that the manufacturer uses the same core and frame (due to practical reasons) for the two motors, whose power does not differ too much.
Zlatkodo
RE: the physical difference between the 50Hz and 60Hz motor
RE: the physical difference between the 50Hz and 60Hz motor
460vac 60hz 100hp motor
... and a
380vac 50hz 80hp motor
wiring differences?
I guess if you were trying to hook up the 460vac 60hz motor to 460vac 50hz power supply, there might be some wiring changes you could make to keep volts/hz roughly constant such as changing to wye for 460v 50hz if original 460v 60hz connection was delta. In that case I think the 50hz rating of the motor might be around 58hp (100hp/sqrt3).
Sorry if I'm not addressing the question. I don't know how OEM's approach it... most of the catalogues I look at only mention 60hz. I'm sure others can add more insight.
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RE: the physical difference between the 50Hz and 60Hz motor
No, generally there is not.
Peter