Motor voltage
- Thread starter j rae
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kingpb
Senior Member
- Location
- SE USA as far as you can go
- Occupation
- Engineer, Registered
It is technically at the lower end of the voltage rating, i.e. +/- 10%. So,
230 x 0.9 = 207V
Keeping in mind that means you have no more than a 0.5% voltage drop from source to load.
With that said, there are other factors such as loading. Is the motor fully loaded or lightly loaded? Is the load to be started require a lot of torque, because the low voltage may not be sufficient?
So, the answer is maybe.
If there is a transformer ahead of the motor, consider tapping it so you get 208V x 1.05 = 218V on the LV side. It gives you a little more margin to play with.
230 x 0.9 = 207V
Keeping in mind that means you have no more than a 0.5% voltage drop from source to load.
With that said, there are other factors such as loading. Is the motor fully loaded or lightly loaded? Is the load to be started require a lot of torque, because the low voltage may not be sufficient?
So, the answer is maybe.
If there is a transformer ahead of the motor, consider tapping it so you get 208V x 1.05 = 218V on the LV side. It gives you a little more margin to play with.
broadgage
Senior Member
- Location
- London, England
It depends on the actual supply voltage and how heavily loaded and well cooled the motor is.
If the nominal 208 volts supply is generous at perhaps 215 volts actuall, then it should be fine since the voltage is well within 10% of the nominal.
If however the nominal 208 volt supply is on the low side at perhaps 200 volts actual at the service, and 195 volts at the motor then it may be a problem.
A 230 volt motor run at 195 volts will draw more current in order to provide the same HP and will therefore run hotter.
If the motor is over sized, perhaps 6 HP but only required to produce 5HP then it should be OK.
If the motor is a continous duty type, but only run intermitantly it should be OK.
If the motor is worked in very cold and well ventilated conditions, then the extra heat should be carried away without it running any hotter, again no problem
If however the motor is to be fully loaded, continually, in a warm enviroment, then I would advise against it.
Either obtain a 200 volt motor, or a voltage increasing transformer, or a larger 230 volt motor in order that it wont be fully loaded.
If the nominal 208 volts supply is generous at perhaps 215 volts actuall, then it should be fine since the voltage is well within 10% of the nominal.
If however the nominal 208 volt supply is on the low side at perhaps 200 volts actual at the service, and 195 volts at the motor then it may be a problem.
A 230 volt motor run at 195 volts will draw more current in order to provide the same HP and will therefore run hotter.
If the motor is over sized, perhaps 6 HP but only required to produce 5HP then it should be OK.
If the motor is a continous duty type, but only run intermitantly it should be OK.
If the motor is worked in very cold and well ventilated conditions, then the extra heat should be carried away without it running any hotter, again no problem
If however the motor is to be fully loaded, continually, in a warm enviroment, then I would advise against it.
Either obtain a 200 volt motor, or a voltage increasing transformer, or a larger 230 volt motor in order that it wont be fully loaded.
That depends if you run this motor from a "stiff" voltage source, because inrush current will drop the voltage even further with a non-zero source impedance, which will shorten motor life rapidly.
Inrush current duration will be less when running a fan than when running a compressor.
Source impedance for 50' of #14 copper @ room temp. will be about 0.26 ohms. For a 3% drop at 120 v you'd be drawing 14 A.
What's your wire gauge and length?
stew
Senior Member
- Location
- federal way,washington
is this motor already installed? If so do a full load running test. Check the current draw against the full load current of the nameplate. If you are running below nameplate current then no worries. Also I would like to know what the duty cycle rating on the nameplate says??
That depends on the parameter of that motor. If the fluctration of that motor allows, you can use the motor rated 230 volts for your voltage of 208.
Hope it helps.
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