?

[resistance]

All checks out well at the main panel. The poco will check there side.

 

[macmikeman]

When you checked the voltage at the main, did you check at the output of the breaker feeding the motor. Maybe you have a loose connection at the main, I would pull the breaker and check for burning on the bussing and then switch the two phase conductors, then see if you have 100v on the other wire. If so the problem is in the main, if the problem follows the conductor then it is the conductor or a splice in the conductor.

Ding, Ding, Ding. Correct answer. It is not always a loose neutral that causes voltage unbalances on specific branch circuits. Impedance problems on one of the conductors will also throw off the line to ground or line to neutral readings. In the absence of higher than normal voltage readings on the "good" conductor this is the likely case.

 

[resistance]

The feeder is a #10 cu, so I don't believe there is too much of a difference between resistance and impedance--based on the conductor size. Yet, i can agree that the distance in this case is playing a vital role---seeing that it's over 150ft. New news: the customer now claims "they" did an underground splice:roll:.

 

[don_resqcapt19]

The current through the motor is not the issue. A difference in voltage from each hot leg to ground, as measured at the motor's location, is the issue. A lost neutral at the panel can cause the two voltages at the panel to become different from each other, as measured to the neutral/ground point at the panel. That would in turn cause a difference in voltages throughout the system.

Charlie,
I don't see that as changing the line to line voltage at the motor. The motor does not see the line to neutral voltages.

 

[charlie b]

I don't see that as changing the line to line voltage at the motor. The motor does not see the line to neutral voltages.

Agreed. But that is not the issue at hand; we are not talking aobut line to line voltage. The OP speaks of L1 to EGC and L2 to EGC.

There is no neutral at the load, and even if there was one it would not be connected to the EGC at the load. So the voltage L1 to EGC as measured at the load will be fairly close to the voltage of L1 to EGC as measured at the panel. That in turn will be almost exactly the same as the voltage of L1 to netural, as measured at the panel. If the two voltages L1-N and L2-N are not close to one another at the panel, then it can explain the symptom described in the OP.

 

[don_resqcapt19]

Charlie,
I was combining questions one and two and assuming they were directly related.