Voltage/Current Imbalance

[Electromatic]

I have a pumping station whose pumps are not running smoothly. We think it's mostly a mechanical/plumbing issue, but while investigating, I found what I consider a significant voltage and current imbalance with a motor running. The motor is 25HP, and the system is a high-leg 240V.
With the motor running, I have:
AB 240V
BC 237V
AC 235V

A 51.5A
B 53.5A
C 44.0A

Oddly, I get similar results with both an old motor and a newly-installed one. Also, there is a backup generator with slightly better voltage balance (238, 238, 241), and running off it, the motor pulls 51A, 53A, 46A.
Is there something I should look for to correct this, or is this a good as can be expected?
TIA

 

[ron]

If you turn the loads off, is the voltage provided by the utility "off-balance" They are generally permitted + or - 10%

 

[Electromatic]

With no major load (no motors, just a couple of lights and small items) I have:
AB 245V
BC 242V
AC 238V

A-gnd 118V
B-gnd 212V
C-gnd 121V

I'm fine with the service being +/-10% from a nominal 240V, but the imbalance concerns me. It's about 11% current imbalance at the motor. However, I don't know that the utility is going to give much thought about their 1.5% voltage imbalance.

 

[LarryFine]

With no major load (no motors, just a couple of lights and small items) I have:
AB 245V
BC 242V
AC 238V

A-gnd 118V
B-gnd 212V
C-gnd 121V

So, you have a high-leg delta. They're never balanced because they're never equally loaded.