how to determine 3 phase panel with a grounded hot leg, panel has three legs a,b,c

[luisaguirre]

measured A to ground 123 volts

measured B to ground 247 volts

measured C to ground 123 volts

measured A to C 247

if so has does a phase inverter work, because i need 400 volts to operate dovetail machine

 

[augie47]

May be too early for my brain, but those numbers only make sense to me if you had an ungrounded delta. In any event, with a phase to phase voltage of 247, you will no get your desired 400 volts.

 

[kwired]

measured A to ground 123 volts

measured B to ground 247 volts

measured C to ground 123 volts

measured A to C 247

if so has does a phase inverter work, because i need 400 volts to operate dovetail machine

If you have voltage to ground on all three lines - I would say none of them are grounded because if one of them were I would expect one of your readings to be zero or very close to zero. What do you have from A-B,B-C?

Your readings sound more like it may be a 120/240 single phase system with grounding/bonding issues, or you have a delta system with a high leg, but if that were the case the voltage from B to ground should have been lower, probably should be around 213 if A to C is 247. I'm leaning more toward the high leg system, except the B to ground voltage is not possible but everything else is.

Not sure what you are asking for certain about phase inverter to get 400 volts, seems to me you need a transformer to get what you appear to be looking for.