I am working in NYC on an old building and mostly every motor controller has its own controll transformer. 480/120. The x1 and x2 terminals on the secondary side read 128 volts when tested to each other. There is no grounded conductor to the x2 neutral terminal (some older transformers have x1 as their neutral).
Taking readings from the fused secondary terminal (usually x1, but sometimes on older transformers its x2) to ground gives inconsistant readings. I believe there could also be a situation where a ground fault on the secondary side would energize the metal components in contact with the ground fault, but would not blow the fuse due to the ungrounded neutral secondary.
Should I install a grounded conductor to the controll (secondary) transformer neutral ??
If I install a grounded conductor to the neutral terminal will the controll circuit operate correctly, or will there be some ill effects ??
I believe it would operate fine, unless there is a fault to ground, and these controll transformers were installed prior to the NEC becoming aware of the importance of grounding and bonding.