View Single Post
  #13   Report Post  
nestork nestork is offline
Senior Member
 
Posts: 2,498
Default

Home Guy:

If bumping the washer caused it to work properly, I expect your capacitors are OK, but the connections are dirty. I don't believe you have a slipping belt. If you did, your laundry room would be full of smoke and you'd smell burning rubber.

I expect you can find the correct capacitor online for under $10. You may have to import it from the States, but that's no big deal, I import stuff all the time and I can tell you how to fill out the Canadian Border Services B3 form, and the procedure to follow to get it across the border. However, keep in mind that even a $10 item will cost $10 to 20 in shipping costs.

The easiest way to understand how a start capacitor works is to understand that there's no such thing as capacitor start or split phase electric motors that use 3 phase electric power. With three phase electric power you simply arrange the poles around the stator 120 degrees apart and you create a rotating magnetic field.

With 120 volt single phase power, you can normally only create an oscillating magnetic field. To create a rotating magnetic field, you have to use some kind of trick to create a rotating magnetic field for the rotor to follow.

The way this is done with a capacitor start motor is to have two identical windings wired in parallel and arranged at a 90 degree spacing around the stator. So you have North pole of winding 1, South pole of Winding 2, South pole of Winding 1 and North pole of winding 2 all spaced 90 degrees from each other around the stator.

Now, we simply wire a capacitor in series with ONE of those windings.

With a resistor, the current is highest when the AC voltage sine wave is highest, and the current is instantaneously zero when the applied AC voltage sine wave is zero.

With a capacitor in series with the start winding, things are totally different. With a capacitor, the current out of the capacitor (and hence through the start winding) is highest when the RATE OF CHANGE IN VOLTAGE of the applied voltage sine wave is highest, and that occurs on the applied sine wave when the instantaneous voltage is ZERO volts. That is when the voltage is changing from a positive voltage to a negative voltage and vice versa. That's 90 degrees out of phase with the winding that doesn't have a capacitor.

Similarily, with a capacitor in the start winding, the current out of the capacitor (and hence through the start winding) is at a minimum when the applied voltage sine wave is at a maximum or a minimum. That is when one plate of the capacitor is fully energized and the voltage on it is starting to drop, the instantaneous current out of the capacitor will be zero. That's 90 degrees out of phase with the winding that doesn't have a capacitor.

Consequently with the start and run winding wired in parallel, the capacitor in the start winding will have it's current sine wave 90 degrees out of phase with the run winding, and as a result, the magnetic field of the start winding occurs 90 degrees sooner or later than the run winding. And, that's true even though both windings have the same voltage sine wave applied to them.

So, the capacitance of the capacitor you use is important. You can just take one from one motor and use it in another.

There is also another kind of induction motor that doesn't use a capacitor. Instead, in a "split phase" motor, winding #1 will be made with a small number of coils of thick copper wire, and winding #2 will be made with a large number of coils of thin copper wire. Because of the difference in resistance of these coils, they have different resulting impedances, and that results in one coil developing it's magnetic field earlier than the other, and that's what creates the illusion of a rotating magnetic field for the rotor to follow.

In both capacitor start motors and split phase motors, the motor is perfectly happy to turn in the reverse direction if you simply reverse the polarity of one of the windings. So, if you switch the wires going to Winding #1, the motor will start with the same torque, and it'll reach the same operating speed, only it'll be turning backwards. Never reverse the polarity of both windings in an induction motor. That will cause a singularity in the space time continuum with the result that you finish doing the switch before you began, and hence the motor turns in it's original direction again.

Maytag washing machines have a reversing relay that automatically switches the wires going to the run winding. That relay is controlled by the timer, and it reverses the terminals to the run winding so that the motor spins in one direction during the wash cycle (where the agitator oscillates) and in the reverse direction during the spin cycles (where the wash basket spins). Most washing machines use this reversible characteristic of induction motors to reverse the direction of rotation of the motor from the wash cycle to the spin cycle. In Maytag's case the motor turns a belt that causes a pulley to rotate up or down a helical shaft. When the pully rides up the shaft it engages clutches in the transmission that lock the transmission up so that the spinning of the pully directly results in the spinning of the wash basket. And, when the motor reverses direction, that pulley turns the opposite way and rides down the helical shaft to unlock the transmission and allow the rotation of the pulley to cause the oscillation of the agitator.

In a case like this, I think your best bet is to got to a factory authorized Kenmore repair depot to buy your parts. It's true that you'll pay more for each part, but you also get all the expert technical support tossed in free of charge. So, you spend a bit more on parts, but you save all the labour by doing it yourself under the tuteledge of a Kenmore appliance repairman.