On Fri, 16 Sep 2005 20:41:28 -0400, Fred wrote:

wrote:
Hi fellow woodworkers:

I have a shop compressor with a 220V induction motor that would not
start. It does not hum or create any noise whatsoever when I flip the
switch. I browsed through groups and through Google but came with
cases when the motors at lease hummed to indicate that they were
getting a juice.

Here are a few diagnostics I ran:

Tested voltage at the switch terminals of the motor. The voltage
across two out of phase leads is 240 volts when the switch is in off
position. The voltage is almost zero when the switch is flicked on.

Power switch works fine and correctly makes and breaks the contacts.

What other tests I need to run before opening the motor housing.

Thanks

Shailesh

These motors have few parts to fail. The start capacitor and the start
(centrofugal) switch are the most likely. Pretty much, the only other
problem you would see is a loose or broken wire.
Fred


Could be but the centrifugal switch in most cases is closed at start
and opens to take the start circuit out of the picture when the motor
gets up to speed. then it is spring loaded to close when the motor
comes down. Usually fails by getting dust between the contacts or a
broken spring. But when it fails you still should get a hum with the
motor trying to start without the start capacitor in the circuit and
having a hard time doing it..




Are you sure there isn't a fault in the pressure switch circuit that
is keeping the motor from starting. I'm not sure how that works but
you might check all that wiring.