[Milsurplus] Aircraft Electrical Question

[Mike Morrow]

>I have couple late sixties dynamotor that produce three phase 115/400 cycle
>that have one leg grounded. So A to B = 120 volts, A to C (with C grounded = 120 >volts and b to C = 120 volts. So it's a true three phase system but C is grounded.

That's a very common arrangement in small aircraft instrument-supply AC inverters.
All of the ones I have use that arrangement.  It is a compromise for delivering
three-phase power (in small capacity) with a minimum of cable connections.

Mike / KK5F