In article ,
Ken Sterling kens_at_sys_matrix_.net wrote:
DoN. Nichols wrote:

Trace that circuit. It may also go through some thermally
tripped switches on the contactor, to drop power when it draws too much
current -- such as when the saw stalls, or when one of a three-phase
feed is open. (Is this powered from three phase?)


Heaters are open circuit it doesn't start when you push the start button,
can't be the heaters. - GWE

You lost the attribution -- the part which you are questioning
was written by: Grant Erwin
not by me.

Maybe I'm mis-understanding - heaters are closed circuit. The
contacts close, current flows through the contact tips, then through
the heaters to the motor windings. If the motor draws too much
current, then the heaters (bimetal springs) trip open and shut down
the current. Heaters can't heat up unless current is flowing through
them. Sometimes a coil wire is fed through a heater so when it trips
out the coil drops out and opens the contactor.

I *think* that what he meant was that if the contacts controlled
by the heaters are open (tripped), then the start button should not move
the motor. I agree with this -- as long as it is correctly wired, with
the button paralleling *only* the hold-in contacts on the contactor
(relay). But, as I have already said in another followup to him, I have
seen mis-wired things in too many places to want to bet that it is
correctly wired. :-)

Enjoy,
DoN.

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