In a message dated 97-11-22 21:01:36 EST, prubrew@ix.netcom.com writes:
> I got a new switch, wired it up and.....The damn thing still "cycles".
> It seemed as though the more pressure built up in the tank, the faster the
> cycling would occur, to the point that it started slowing down the motor.
> I'm starting to think maybe I just got too small a motor.
Chris:
I'm going to make a few guesses here. If the motor were shutting off because
of overload, It probably would not restart till you pressed in a circuit
breaker on the motor itself. I don't suppose all motors have this, but most
of the ones I've seen do. Never-the-less, The motor wouldn't "shut off" if by
shut off you mean it acts as if the power has been cut to the motor. Just
stopping from overload would be quite a different sound. It would grunt, or
hum, loudly, till you cut off the power.
Monitor the voltage to the motor. If it is cutting in and out, you will see
it at the input terminals. If it is an internal cutout on the motor, the
voltage at the input terminals will always be there, but power will be killed
inside the motor itself. There may be an automatic reset circuit breaker in
the motor frame somewhere.
If the power is being cycled on and off TO the motor, then your switch is the
problem. I don't know that much about pressure switch operation to help with
that.
One thing you might try, if nothing else give you a clue. Try wiring the
motor directly to power, bypassing the switch, and see what happens. Be
prepare to quickly disconnect the motor, though, just in case it is severely
overloaded, and watch the gauge for pressure peaks.
What size is the storage tank? it may be that it is small enough to fill to
the shutoff point very quickly, and maybe go to the bleed off valve setpoint
to let out enough air to reset the switch.
As I said, these are just wild guess from here. If it's any help, you have my
sympathy. I know how frustrating things like this can be.
Dan Masters,
Alcoa, TN
'71 TR6---------3000mile/year driver, fully restored
'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
http://www.sky.net/~boballen/mg/Masters/
'74 MGBGT---3000mile/year driver, original condition
'68 MGBGT---organ donor for the '74
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