Originally Posted by Frank S

He wouldn't the center tap of the secondaries would be grounded to earth leaving 2 hot wires each having 240 volts or most probably 230v with those he could connect to 2 legs of the 3ph idler motor, and connect his load to all 3 of the legs. A bank of capacitors would help to smooth out the 3 ph out put but not entirely necessary if he has a fractional hp single ph motor to spin up the idler motor.
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To Frank S

If you connect the idler motor as you describe above with 480 volts SINGLE PHASE across two terminals of a three phase star wired motor rated for 415 volts (if wired for three phase delta it would be rated for 240 volts) you will be applying 277 volts across each idler motor winding, not 240 volts!
It appears both "old kodger" and "nhengineer" do not understand how a three phase 240 volt delta/415 volt star motor works much less how to connect one.