# Will 400V, 50hz, 3phase, 3A, 1.5KW motor run safely on 440V, 60hz power



## Trike1903

I have a German mill (Optimum F30) and the motor label says 400V, 50hz, 3phase, 3A, 1.5KW. Can I safely plug this into a 440V, 60hz power power supply. I realize the RPM will be effected but will it hurt the motor?


----------



## Micke S

3-phase motors will normally not be damaged by +/- 10 percent over/under voltage. The motor will spin about 20% faster due to 60 Hz. It will also draw more current due to the higher voltage. So the motor will be more stressed. But in case it was me I would make a test and check if the motor can be used under the conditions you state. Don't blame me though if problems occur.

It would not be wrong to listen what the manufacturer will say if you ask them http://www.optimum-maschinen.de/produkte/fraesmaschinen

http://www.optimum-machines.com/contact/index.html


----------



## Ulma Doctor

it's not going to hurt the 50 hz motor to run it on 60hz.


you would not want to run a 60Hz transformer on 50hz, 
the transformer would experience high temperatures as a result trying to operate at a lower frequency.


----------



## John Hasler

Trike1903 said:


> I have a German mill (Optimum F30) and the motor label says 400V, 50hz, 3phase, 3A, 1.5KW. Can I safely plug this into a 440V, 60hz power power supply. I realize the RPM will be effected but will it hurt the motor?



In the name of "harmonization" the EU invented new standard voltages with wide enough tolerances to include existing national standards.  

http://www.schneider-electric.co.uk...t&country=UK&lang=en&id=FA163890&locale=en_US

You should be ok.   You're slightly above the design voltage maximum but the higher frequency will make up for that.


----------



## Micke S

The reason I was a bit careful in the answer is that line voltages will vary. A motor that is designed for 400 V is normally able to handle up to 440 V (+10 %). This gives room for using it in a 440 V system IF this will be the ACTUAL voltage. But when 440 V is the nominal voltage it can be up to about 485 V depending in where you are connected in the distribution chain and other factors. So the risk for a real over-voltage situation is much higher.

A simple solution is to have a volt meter connected and take a quick look on it when the machine is used to see that the actual voltage is within a reasonable level (e.g. below 445 V or so) :bitingnails:.


----------



## JimDawson

Mike S you are correct to be a bit concerned. The North American power grid is a nominal 480 Volt system.  I have never run a 400 Volt (nominal 380 volt) European motor on 480 volt without a transformer.  Normally one would install a 3 phase auto transformer to buck the voltage.  (see Buck/Boost transformer)

A VFD would work in this application and just program the output voltage limit to the correct value.


----------



## Micke S

Good info Jim. I would not connect a 400 V motor to anything that normally produces 480 V. There are  also transients (voltage spikes) in any power system that will raise the voltage more for short periods.

Some equipment like certain high end VFDs are designed to handle all this for several markets. Then they are rated for e.g. 380-550 V input voltage.


----------



## mzayd3

If you keep the volt : hertz ratio the same, there is no harm done.


----------



## John Hasler

mzayd3 said:


> If you keep the volt : hertz ratio the same, there is no harm done.



Right.  It's the same as if you running the motor on a VFD powered by 50Hz 400V and pushed the speed up to 120%.  The VFD would raise its output frequency to 60Hz and its output voltage to 480V.


----------



## Micke S

John Hasler said:


> Right.  It's the same as if you running the motor on a VFD powered by 50Hz 400V and pushed the speed up to 120%.  The VFD would raise its output frequency to 60Hz and its output voltage to 480V.



I agree this is how it should be to keep the torque at a constant rate above the nominal frequqncy. But when I now checked my two VFDs, one Chinese and one High End Danfoss VFD, they both bottom out at the same voltage as the line voltage (400 V). The voltage is however reduced proportionally from 400 V when the frequency is decreased.


----------



## Wireaddict

I don't think you'll have any problems either, certainly not for 5 minute test.  During that time you can check the motor & any controls such as a motor starter for early signs of overheating which would give you ample warning in this case.  One thing that hasn't been mentioned, though, would be incandescent lamps & DC electronic components because they'd receive 20% higher voltage than normal which may exceed their rating & shorten lamp life slightly.  Check on that before powering it up.


----------



## Trike1903

Thank you all for the help. I checked the voltage and it reads 441. The voltage comes from a transformer that is suppose to output 440. A 20 minute test did not show any heat or power problems. You are correct the spindle does turn faster. I will be machining 1/4 steel , 1/2 brass, and aluminum. I will be drilling and boring 1/2 steel. So I will not be taxing the system very much. 
Thanks again for the help, you can take the rest of the day off.


----------

