It looks like most of the crisis is over. It turns out that there is a
voltage regulator knob control which if you turn, you can vary the voltage
on the 208 tap up to 240.
I have worked the pumps off backup power now for the first time and all
appears ok.
I did find a wiring error at the pump subpanel which explained why that
breaker tripped at the SEP when I first tried all this.
Also, I did not have to disconnect the neutrals of the mains and backup
power; I can switch between the two entirely at the transfer panels.
A lot of good came of all this as I have learned a lot more about 3 phase
power and backup generators.
Thanks for everybody's help.


--
don paolino
"RBM" rbm2(remove wrote in message
...
If your single phase pumps are designed for 240 volt, I wouldn't use the
208
volt tap. Your phases are 1-2, 2-3, 1-3, so if you are using two of them
as
single phase, you are doubling up on one leg, so it does limit the
capacity.
You may be better off to connect it as a Delta, and just use the single
phase 120-240 volt taps



"desperado" wrote in message
.. .
I bought an old Army Corps of engineers 30kw 3 phase genset with
Hercules
DD298ER 6cyl motor.

The numbers on it say GE 5SJ4324Y2Y6

Jetta power
stock no 6115 976 8982
mfg 1964

I want to use it to back up my main power on my ranch. I have 240V
single
phase service coming in from Southern Calif. Edison.
My main panel is 100Amp single phase.
Genset has a busbar of 12 leads which can be reconfigured for 120/208
240/416 or 120volt delta .
Right now the 120/208 has been chosen. I measured 217V no load coming
out.
There are 3big split bolt connectors coming out and one smaller one
which
appears to be the neutral or ground. Right now, 125v is measured from
this
point to each of the big split bolts.
I decided to use one phase to power the whole house less the well pumps
and put the well pumps on the second phase. That is because the amps per
phase is listed as only 57 amps in this configuration and I figure I
since
the pumps take 9 amps each running and there are two of them, that this
would leave more amps available to power the house on the other phase.
This
leaves the third phase not connected to anything(open circuit.) as a
spare.
I bought some transfer panels(double pole double throw) and have brought
the well pump 30amp dp breaker wires out to a separate 60a transfer
panel
and connected it to one of the phases of the genset. the other phase I
put
into the 100amp main breaker and a 100 amp transfer panel.
I am a retired electrical engineer but my specialty was microwave and
antenna design and not power engineering.
Is this setup ok or do I have to install more equipment?