480/60hz motors running on 400/50Hz

[doug glasscock]

The plant in europe says their voltage is 400V/50Hz.

What affect does running the 480v/60Hz motor at 400V/50Hz have on Horse Power. I know it will run 5/6 the speed, but I am unsure about the HP.

 

[tom baker]

Re: 480/60hz motors running on 400/50Hz

The NEMA voltage tolerance is +/- 10%. The lower voltage will cause a big increase in amps, torquie will drop off, and its a violation of 110.3(B).

 

[frenchelectrican]

Re: 480/60hz motors running on 400/50Hz

also most electric motor manfactures will listed for hp rating and s.f. (service factor ) will derated to 1.0 some case less and the horsepower will some case stay the same or less really the best best is check on the manfacture of electric motours ( i am organally from france ) and yes it can be confused the speed will drop and horse power rating will somehow drop also so . and nec codes have specal side bar i cant find it. but most motor have specal rating on it so just check out the manfactures .

tom : read the HZ again usa have 60 and european have 50 HZ and it do apply diffrent speed and hp and toqures it do change a bit

merci marc

 

[Ed MacLaren]

Re: 480/60hz motors running on 400/50Hz

The motor should operate OK as long as the volts-per-hertz is maintained, and it appears that this is the case.

This would be no different, in principle, than a Variable Frequency Drive set at 50 Hz

I'm not sure what the reduction in HP would be.

Ed

 

[gramps]

Re: 480/60hz motors running on 400/50Hz

Example:-->a four-pole motor's synchronous speed is 1800 r.p.m. at 60 hz., and approx. 1500 r.p.m. at 50 hz.(no load). since output power=torque X motor speed, the motor will have to draw more amps. to produce the rated output power. in doing this, there is a possibility of "core saturation" occurring, with serious overheating problems, and winding failure as the final result. same scenario as trying to operate a 60 hz. transformer at 50 hz. you'll have to de-rate the motor's power factor and reduce its load to compensate.


hope this helps,
gramps


ps: forgot to add this comment: you'll need to look at re-sizing the operational controls too, if your going to run the motor with a higher current draw.

[ March 13, 2003, 06:57 AM: Message edited by: gramps ]

 

[Ed MacLaren]

Re: 480/60hz motors running on 400/50Hz

the motor will have to draw more amps. to produce the rated output power.

It goes without saying that the motor's nameplate full-load amps (FLA) rating cannot be exceeded, therefore, as in the case of VFD control of a motor, it is understood that a motor that is "oversized" for the load will be required.

Doug's question is, as I read it, - by how much? I recommend that the motor manufacturer be consulted.

Provided the setting (or heater selection) for the motor's overload relay is based on the nameplate FLA and Service Factor (SF) ratings, the windings would be protected from overheating no matter which voltage/hertz it is operated at.

However, some motors are not suitable for use with a VFD due to balance problems, and reduced cooling fan efficiency.

Ed

[ March 13, 2003, 10:32 AM: Message edited by: Ed MacLaren ]

 

[jcormack]

Re: 480/60hz motors running on 400/50Hz

The Volts/HZ ratio is being maintained - there is no problem running this motor with this input. the vast majority of motors are are designed to run at 50 hz for European use - ABB motors for example typically have both 60/50 numbers stamped on nameplate - Reliance & GE only put 50 hz data on motors going overseas - Typical derate would be 1.0 on a 1.15 sf motor (HP is related to RPM, so derate 15%), but consult motor provider.

 

[gramps]

Re: 480/60hz motors running on 400/50Hz

motors of cast-iron construction are much more susceptible to the "core saturation, over-heated windings" scenario, than motors made from aluminum or stamped steel. the cast-iron doesnt dissipate heat nearly as well. thats why some of the TEFC motors dont fair very well, under these conditions. i agree that some of the motors wont have a problem, at least in the short-term.


gramps

[ March 13, 2003, 02:33 PM: Message edited by: gramps ]

 

[doug glasscock]

Re: 480/60hz motors running on 400/50Hz

Just wanted to thank everyone, AGAIN.