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DoN. Nichols
 
Posts: n/a
Default electric motor forward/reverse wiring?

According to Jordan :
DoN. Nichols wrote:


[ ... ]

So -- it is a workable circuit for *your* motor and *your*
country's wiring -- but it won't work here in the USA. In particular,
even if he had a motor with a 240V start winding, the RUN/STOP toggle
switch would need to be DPST to open both hot windings for safety
reasons.

Thanks DoN
I've left out the earth, which is a third wire.
I thought that some parts of the USA had 240V system like here in Australia.


Well ... most parts of the USA have 240V available in the homes
along with 120 -- but most loads are 120, so the design is a center
tapped transformer providing 240 between the ends, and 120 ether side of
the center tap. So -- unlike your 240V, ours has neither side grounded,
but instead floating at 120V above ground. As a result, it changes
what is a safe circuit, and what is not.

I thought also the drawing might shed some more light on the problem.


It did -- for the motors which you have available, and it showed
the principle that you had to reverse the connections to either the
start winding or the run winding -- it doesn't really matter which.
(But his motor was hiding the presence of the windings -- just giving
you wires to move around without showing what they were connected to.
:-) It took me a bit of time to figure out what was really in that
motor, based on what connections were being shown. And I've *worked*
with that kind of motor before.

Hope I didn't confuse anyone too much.


I don't think so. And you were trying to help -- though you
didn't at that time understand the difference between our 240V and
yours.

Thanks,
DoN.
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