6 wires 3P motor with no diagram for connection 240 or 480?

[don_resqcapt19]

If you just take a 480V (or 460V) Wye connected motor, each phase winding would be 277V.

That is correct, but if you take that very same motor and connect it delta, and supply it with 480, you will smoke it because you are applying 480 volts to a 277 volt winding. It will work fine delta connected with a phase to phase or supply voltage of 277 volts as the windings are getting their design voltage. This is a 1.73 to 1 ratio.

you are saying but you're still confusing the voltage across each phase with the voltage rating of the machine.

No I am not. Lets try this another way.
If you have 3 single phase transformers with a secondary voltage of 240 volts, and you connect them in a delta what will the phase to phase voltage be? Now reconnect those same 3 transformers in a wye and tell me what the voltage is.
Don

 

[james wuebker]

Jim,

Just got done wiring a Siemans 5 hp motor with 6 leads. Either 240 or 480.

How does that work? I thought that the two voltages on a 6 lead motor had to vary by a factor of 1.73 to 1 and not 2 to 1. It is my understanding that you change the voltage on a 6 lead motor by connecting in a wye for high voltage and a delta for low voltage.
Don

Don, On this Siemens motor there's 6 leads, U1,U2,V1,V2,W1 &W2. For 240v you connect (delta) W2+U1+L1, U2+V1+L2, V2+W1+L3. For 480V you connect (Y ) W2+U2+V2 connect together then U1+L1,V1+L2,W1+L3. This is how I wire this Siemens motor.
Thanks!
Jim

 

[don_resqcapt19]

Jim,

On this Siemens motor there's 6 leads, U1,U2,V1,V2,W1 &W2. For 240v you connect (delta) W2+U1+L1, U2+V1+L2, V2+W1+L3. For 480V you connect (Y ) W2+U2+V2 connect together then U1+L1,V1+L2,W1+L3. This is how I wire this Siemens motor.

In that case the coils will see 240 volts when connected for low voltage and 277 volts when connected for high voltage. My only point is that you cannot not have a true 480/240 volt six lead motor. I'm sure that the motor is designed for this application and that in the 480 volt connection you actually have a more with more horsepower than the nameplate shows, however if the FLA is in a 2 to 1 ratio, the required overload protection will limit the use of this additional horsepower.
Don

 

[scott thompson]

teal854t,

I am a bit late to this thread, but wanted to post this anyway.

Does this Schematic look anything like your Motor?

This drawing is located at ECN's Technical reference area, under the topic:

3 Phase Wye Connected Motor Drawings #1

Scott35

 

[relbas]

Maybe this motor is a part winding start up?

Is is pre wired with 6 leads in the splice box.

 

[don_resqcapt19]

This motor is a 6 lead dual voltage motor. Delta run for low voltage and wye run for high voltage. My whole point with my comments is that the name plate shows the motor as a 480/240 volt motor. I'm sure that the motor is listed and tested for those voltages, but a 2 to 1 voltage change is not possible with a 6 lead 3 phase motor. The actual change is 1.73 to 1. In the case of this motor I expect the the internal coils are designed for 240 volts and operated at that voltage for the low voltage (delta) connection and operated at 277 volt for the high voltage (wye) connection.
Don