Ungrounded 480 volt delta generator

[tc78]

I work for a oil and gas drilling company. We have a 480 volt 3 phase delta generator suppling power to several 480 volt delta motors. My question is: Is it necessary to use a resistor or transformer to provide a phase to ground fault return path for this setup. We do have a active ground fault alarm system.

The generators are ungrounded (no return current path) to provide for safety to the personnel in the event of a phase to ground contact by the rig personnel.

 

[charlie]

Consider a generator output the same as a transformer. 480 volt output does not have to be grounded as a system but the generator itself must be connected to the grounding system. Ground detectors are also required to be compliant with the NEC which you already acknowledge having. It sounds to me like you are good to go. :smile: