What are the drawbacks of Using a 50hz motor on a 60hz system
What are the drawbacks of Using a 50hz motor on a 60hz system
(OP)
Question for you guys, I work in a industrial plant that is owned by italians but we are located in north america. The spare parts we recieve come from our parent plant in italy. We have been dealing with alot of premature motor failure in the plant and i was curious if it could be related to the name plate rating's on the motors. I.E. we have a machine that uses a 18.5kw 1440rpm 50 hz motor that cycles on/off around 20 times a minute. I was wondering if running this motor on a 460v 60hz supply could be leading to the motor failures. We are getting an average life of around 4 months per motor. These motors are not locking up bearings, most all are burning up the windings.
Thanks
Thanks





RE: What are the drawbacks of Using a 50hz motor on a 60hz system
Doing this with 20 % higher speed than rated causes 44 % more rotor losses and correspondingly higher stator losses.
That, coupled with the fact that the cooling isn't active all the time, will definitely shorten motor life. And it is, in my mind, no wonder that your windings are burning.
I can guess that the motors live somewhat longer in Europe. But probably not the 10 - 20 years you expect from an induction motor.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: What are the drawbacks of Using a 50hz motor on a 60hz system
I agree with Gunnar - this is probably not going to work well for any induction motor of this size. You really need to rethink your process and find a way to reduce the number of motor starts/stops.
David Castor
www.cvoes.com
RE: What are the drawbacks of Using a 50hz motor on a 60hz system
Speaking of leaving things out, can we assume the motor was rated somewhere between 380 and 415V at 50Hz?
What kind of load?
Why is is cycling so fast?
Was the motor over sized for the load in order to accommodate the high duty cycle? If so, did anyone consider the effects Gunnar mentioned when operating in 60hz power?
In other words it might be as simple as using a larger motor to allow for the added heating effect of running it here. But if the load is a centrifugal pump for instance, the load on the motor will actually increase to 172% with a 20% increase in speed! (However I can't imagine a centrifugal pump cycling every 3 seconds.)
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RE: What are the drawbacks of Using a 50hz motor on a 60hz system
thanks for your imput.
RE: What are the drawbacks of Using a 50hz motor on a 60hz system
I agree with the others. This would probably be borderline at 50 Hz. and is tougher on the motor at 60Hz.
Bill
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"Why not the best?"
Jimmy Carter
RE: What are the drawbacks of Using a 50hz motor on a 60hz system
It is all about accelerating to a higher speed which means speed ratio squared. Good that you have external blowers.
Extrusion means that torque also increases with speed squared (usually) because it is viscious load. That doesn't exactly help. Jraef mentioned that. An increase from rated to 1.72 times rated is nothing to take lightly. A magnetic or hydraulic clutch as proposed by waross, is probably the way to go. Remember to cool the clutch, as well.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: What are the drawbacks of Using a 50hz motor on a 60hz system
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: What are the drawbacks of Using a 50hz motor on a 60hz system
RE: What are the drawbacks of Using a 50hz motor on a 60hz system
So i'm guessing that the particular relay could work for both 50Hz and 60Hz system.
RE: What are the drawbacks of Using a 50hz motor on a 60hz system
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: What are the drawbacks of Using a 50hz motor on a 60hz system
Muthu
www.edison.co.in
RE: What are the drawbacks of Using a 50hz motor on a 60hz system
Isn't language an adventure! I still remember struggling to get along in Swedish and having my rep keep telling me "It can't be that hard. I see little children speaking it every day!"
It was always said kindly and in jest so it is a pleasant memory.
RE: What are the drawbacks of Using a 50hz motor on a 60hz system
You have not told us the most important thing: what is the full-load and no-load currents of motor?
Without these details it is difficult to say anything.
Zlatkodo
RE: What are the drawbacks of Using a 50hz motor on a 60hz system
I suggest you do a sizing analysis on this application, or get someone who can. Twenty starts per hour is not crazy, but is tough for the wrong motor. I know that SEW Eurodrive has an Engineering Manual that goes through a very rigorous methodology that sizes their motors including a given starts per hour quantity. It usually results in applying a larger motor for a given application just to absorb & dissipate the heat generated from frequent starts.
TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering
www.bluetechnik.com