On Thu, 2 Nov 2017 22:15:02 -0400, "Jim Wilkins"
wrote:

I have a 5.5HP, 3750W generator that struggles to start a 1/2 HP motor
on an air compressor, as long as the tank pressure is low. I can't
measure the compressor motor's torque vs RPM curve but it clearly is
drawing that much electrical power at startup.

That's a 10x start-load! I've read that motor startup uses 4-10x the
current, but most I've seen were closer to 4x. That's a biggie.

Have you tried an idler pulley setup to remove the flywheel load from
the motor on startup?

Is it time to plumb in an unloader/pressure switch, or does it already
have one? http://tinyurl.com/yb6f8hgu

Any way to wire in a start cap to help with the current onrush?

Have you verified the genset specs under load?

Are you trying to fix this, or is it posted here only as info, since
the genset does start the compressor?

--
The Road to Success...is always under construction.
--anon