220v Clothes Dryer Switch acting like a Momentary

Discussion in 'General Electronics Chat' started by kcarring, Jan 23, 2011.

  1. kcarring

    Thread Starter Member

    Jan 22, 2011

    My Dad recently replaced the motor in his 220v clothes dryer, and when it was all assembled... the motor turned, the heat came on, and the functions appeared to do their job, i.e. the fluff cycle did not produce heat.

    He is quite certain everything got connected as per how it was connected before and the new motor is identical to the old. The original problem, a grinding sound, went away.

    Here is the catch. The ON/OFF switch, which normally is pressed (button style) -now- needs to be "held in", and is acting similar to a momentary switch in the sense that when it is released, everything shuts down.

    Any hints on an approach to analyze this would be helpful, thanks. It was my thinking that it would not be the sailswitch (if there is one) nor the high limit switch, and that "coincidentally" the switch itself gave up the ghost. That'd be the easy assumption and I'll start by looking at that, but perhaps someone has some other insight.

    Last edited: Jan 23, 2011
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    The dryer should have a switch that indicates when the drum is spinning. If it is not happy, power will not be maintained to the motor.

    There should be a wiring diagram on the rear panel. It should indicate the drum switch and associated wiring. If there is no diagram, you may be able to find on online using the model number.
  3. Hagen

    Active Member

    May 8, 2010
    On most driers, the motor has a starting switch which is operated by a centrifugal mechanism inside the motor. The switch incorporates several sets of contacts which change state when the motor is up to speed. One set of normall closed contacts open to remove power to the starting winding. A set of normally open contacts close to enable the heating element or gas valve. Finally, there is another set of normally open contacts which interrupt power to the motor unless the motor is up to speed, and must therefore be bypassed by the momentary button if the motor has stopped for any reason.
    I know you said the motor was the same, but make sure it has the same switch connections. Good luck!
  4. kcarring

    Thread Starter Member

    Jan 22, 2011
    Thanks very much!

    The picture below is not the exact motor but very very close, in fact visually I cannot tell the difference.


    The entire white surrounded area slides out as a module and the white lever arms are slipped into a spring loaded plastic bushing that would appear to, as you say, possibly "fly out" under centrifical force to operate those arms? ...

    Before I read your post, this is what I did:

    1. The old motor started, and stayed started, it's problem was that it made a heck of a grinding sound so...

    2. I took the connections module out of the old motor, and put it in the new motor. This consisted of a black module that slid in and connected to three windings leads + all the wires coming in from DC source, and various control switches (high limit? sail switch maybe?)

    3. So, after the module was in (the one from the old motor now mated to the new motor) it displayed the EXACT same symptoms: The on off button must be held in to keep the motor running, however heat does come on. As soon as let the button release, everything shuts down.

    I find this odd because the old motor never had that problem at all.

    So ...

    are you saying that the actual "switch" is a centrifugal mechanism that "kicks" those arms on the connections module, and that if the problem is in that centrifugal mechanism, my attempt to fix it would fail, cause I wasn't swapping out the actual component that physically operates the switch?

    Am I understanding, that, correctly?

    Is there any hope for this situation as you see it? Any hints on what I should be looking at next?

    Before giving up on the works I would attempt to make one motor out of both, is possible. Or, i would consider a "work around" to hard wire the main windings into a switch arrangement that would make the dryer work. I hate to give up on something when it will spin and make heat. Frustrating. If I was faced to hard wire it, and just not leave it run unattended I'd do that for a bit, anyway. This stupid dryer had been an unbelievably poor unit, however... it's hanging up in the top of a closet, the controls are on the bottom and it is front load, and guess what - GE are the only people making one like this, of this dimension - so just picking up another dryer is not an option, thus the quest to make this work.

    Thanks very much.
  5. kcarring

    Thread Starter Member

    Jan 22, 2011
    Thanks, I will look into that too, another possible cause, if the case.
    Much appreciated.
  6. kcarring

    Thread Starter Member

    Jan 22, 2011
    I've read these responses and also a couple of posts on an appliance repair forum, and i am starting to suspect that when the dryer was reassembled, the belt tensioner idler arm was possibly not placed properly such that it might have to engage a belt switch, that in turn makes sure the run coils on the motor are energized. The one end of the arm was difficult to see,, I'll check it out tomorrow. Thanks for your help!