JknSD
Member
- Location
- the west coast
I have a pump house that runs on 3 phase 480.
I am trying to understand the phase arrangement.
My reading we as follows, and yes the utility verified it is correct.
A to ground, 480
C to ground, 480
B to ground, zero
A to B, 480
A to C 480
C to B 480
the amp readings under load were A/ 18 amps, C 18 amps, B phase has 18.2.
I have never seen 3 phase that did not have the same nominal voltage to ground, with the exception of a High leg delta.
I am puzzled by the A to C phase reading being the same as the phase nominal voltage. I also am puzzled by the B phase carrying just slightly more current than the A and C phase. Possibly due to the step down trans for the control system voltage?
Any info would help me with this puzzle.
Thanks,
John
I am trying to understand the phase arrangement.
My reading we as follows, and yes the utility verified it is correct.
A to ground, 480
C to ground, 480
B to ground, zero
A to B, 480
A to C 480
C to B 480
the amp readings under load were A/ 18 amps, C 18 amps, B phase has 18.2.
I have never seen 3 phase that did not have the same nominal voltage to ground, with the exception of a High leg delta.
I am puzzled by the A to C phase reading being the same as the phase nominal voltage. I also am puzzled by the B phase carrying just slightly more current than the A and C phase. Possibly due to the step down trans for the control system voltage?
Any info would help me with this puzzle.
Thanks,
John