On 7/28/18 3:25 PM, trader_4 wrote:

Separate system? Where did that requirement come from? Three phase
AFAIK is generated from 3 windings on the same shaft, separated by 120 deg.
Do diesel 3 phase generators have 3 motors? What's does a "separate system"
even mean? They can't be really separate and be locked at a fixed phase separation.

I guess this is as good a place as any to ask since you mentioned
diesel
generators. Most irrigation systems are powered by three phase 480. A
lot of those are generator powered. The power unit powers the well via
a power take off and also a belt driven generator on the front end.
The system motors driving the towers are three phase 480. The
control circuits are 120. So there's a transformer for the 120. It
takes two lines of the 480 and kicks it down to 120. There is also a
tap on that transformer secondary supplying 24 volts. What would you
call that?