determining input voltage

[Armstrong13]

a question from a noob

how can you determine the input voltage of an electric motor with only the ampere rating is given, the motor is ac, im finding a hard time determining whether its 110 or 220.

thanks!

 

[davenn]

have you got a photo of it ?

Dave

 

[ohfour]

Do you know the power factor of the motor? It should be printed on the motor's rating plate (but then so should the voltage, so who knows).

If so, you should be able to measure the winding resistance(s) and calculate the winding impedance using the resistance and power factor. Then you can use the impedance and rated current to calculate what the voltage ought to be.

 

[Armstrong13]

the plate shows

input = 71 B 14
amp = 7.5
WGR (?) = 0 40
there is power portion on the data plate but there's nothing in there

thanks!

 

[ohfour]

Can you take a photo of the motor and rating plate? Or google the model number?

 

[larsen81]

Its true, photo copy of the motor gives a clear view and can able to get model number.

 

[Electrobrains]

the plate shows

input = 71 B 14
amp = 7.5
WGR (?) = 0 40

I suppose you are in North America and it's a 1-phase, asynchronous motor!?
How about just connecting it to 110V and measure the current? For sure it will not be damaged at that voltage.

Of course the 7.5A is specified at full load. Maybe you can try loading it a bit and see what current you reach?

See how it starts up (if possible under load). If it's tough and slow to speed up, it's probably a 220V type.

Also, you can let it run on 110V (and 220V) for a while and measure the temperature. Without load the motor must not get "very warm".

You can compare size and weight with other similar motors. Either a 0.8kW or a 1.6kW motor.