Motor Problem

[PhillDubya]

Been a while...

Another question for the pros here.

Control System Problem

If I told you I had a single phase motor with:
3 leads, one common, one forward, and finally, one reverse, and I was having a controls issue, and just for grins I measured the voltage between each of these leads, and ground, and got a 220VAC. Now, the motor is NOT running, it is NOT bad, and it is not drawing current, what would you say it was? How is this even possible?

I am baffled... I have this Beckwith: The Control This is where I thought the problem was, but I have a manual control that circumvents the Beckwith tap changer, that will not operate the motor either, yet, again, there is 240 between each of the motor leads and ground???

Your thoughts are appreciated as always.

Thanks

 

[BrownOut]

Your screen name cracks me up!

How do you know the motor is not bad?

 

[PhillDubya]

Your screen name cracks me up!

How do you know the motor is not bad?

Dubya needs some help!

To answer your question...
Winding resistance measurements are good. This is how I know the motor is good.

 

[BrownOut]

My guess is there is an opening somewhere in the controller feeding the "common" connection. I'd try bypassing the common on the board.

 

[PhillDubya]

My guess is there is an opening somewhere in the controller feeding the "common" connection. I'd try bypassing the common on the board.

Yeah, but I have 220VAC on the common. Is there any reason why you would ever intentionally put a voltage on all three of the terminals?

To lock the motor maybe? I am grasping at straws...

Thanks

 

[Diver300]

Usually the common line would be at 0 V. If there is no connection to the common line and the power is applied to one of the other connections, the common will appear at 220 V if you measure with an voltmeter.

You are just measuring the supply voltage. As there is no current flowing, there is no voltage drop across the motor.

 

[PhillDubya]

The 250VAC on all three terminals was a grounding issue, yet didn't solve the problem.

Thanks for all the help. Have yet to figure the whole problem out yet, will update.