3 phase 240 with 208 high leg

[sketchy]

How would machines and motors react to changing from the delta high leg to a 120/208 wye system? Burn them out, not work at all?

 

[roger]

In many cases motors are dual rated and will be fine except they will operate at less capacity, as far as machines go, you would need to look at any control transformers and make a tap change if necessary.

Roger

 

[gar]

120924-0856 EDT

sketchy:

If the motor is rated to operate at 208 and the mechanical load remains approximately the same, then the motor current will increase by about 15% compared to its running current at 240. There won't be much change in slip, thus RPM is about the same.

.

 

[Strathead]

In many cases motors are dual rated and will be fine except they will operate at less capacity, Roger

What does this mean? I thought that an AC motor would produce the same amount of torque and RPM and horsepower at 208, or 240V That the amperage would increase inversely to the voltage to compensate. Meaning that a dual rated (208/240) motor has the insulation rating for 240V and the wire ampacity for the 208V.

 

[roger]

What does this mean? I thought that an AC motor would produce the same amount of torque and RPM and horsepower at 208, or 240V That the amperage would increase inversely to the voltage to compensate. Meaning that a dual rated (208/240) motor has the insulation rating for 240V and the wire ampacity for the 208V.

And you are correct, I didn't give any thought to my answer, just shot from the hip.

Roger