PDA

View Full Version : A 50 Hz motor running on 100 Hz



Burrah Boy
03-06-2010, 07:00 AM
Hi people, a youngster in the trade asked me if a 3 phase 380V 50 Hz motor could run at 100 Hz via frequency drive.
The point is they want more RPM out the motor.
I said no, but dont think I gave him the best reasoning behind it. (Maybe I am wrong).
Wouldn`t speeding up the motor cause problems with a faster rotating rotor, and thus have balancing and centrifugal force issues? And what about the bearings?
What about the stator generating more heat!
Could someone please shed more light on the matter.
thanks!

goshen
04-06-2010, 02:27 PM
Hi people, a youngster in the trade asked me if a 3 phase 380V 50 Hz motor could run at 100 Hz via frequency drive.
The point is they want more RPM out the motor.
I said no, but dont think I gave him the best reasoning behind it. (Maybe I am wrong).
Wouldn`t speeding up the motor cause problems with a faster rotating rotor, and thus have balancing and centrifugal force issues? And what about the bearings?
What about the stator generating more heat!
Could someone please shed more light on the matter.
thanks!
Hi :
the answer is yes ,you could do it ,i know because i tried it ,
but you must pay attention :

you need approval from the manufacturer.
if you are turning a fan you will probably push it beyond the design specs ,and will have no rewarding affect.
the higher the frequency the lower the torque !!!
so basically pushing a motor this fast will probably on the long run trash it ,due to mechanical failure!
good luck:)

monkey spanners
04-06-2010, 07:50 PM
How quick does the existing motor turn? You may be able to get a 2 pole motor if the existing one is four pole, a two pole one will turn at around 2800rpm.

sachin230
08-06-2010, 09:12 AM
You should take care of safty things i.e proper earthing termination to motor body.safty settings for motor.
Exceed the motor design specification.Freq Invertor will trip due to motor electrical/mech failure.Its depend upon the application.
better way to change the motor pole or replace the motor for required rpm

Peter_1
09-06-2010, 11:38 AM
What kind of motor? On a fan, a train, a compressor, a pump, a hacksaw,...:confused:
Every motor is designed for its proper working range. So if you go beyond it, then you're never sure what will happen. But certainly premature failure.

chilliwilly
20-06-2010, 04:34 AM
Hi new member here sticking my nose in on this thread.

Won't a motor only do what it says on the tin no matter what you shove in it? Like the other posts say it will just get hotter and produce no more torque. Well hardly any more any way.

kkboy
20-06-2010, 05:27 AM
if you need more RPM just turn it up to 60Hz. If you need to double the Frequency to get the desired RPM then whats in there at the moment is too small