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Back to the the EXPLAIN PUMP SWITCH operation

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Posted by amdx on July 24, 2014, 5:10 pm
I had a previous thread, but ignore it as I have the details correct  
this time.

  To start the motor did spin when powered.

I helped my neighbor disassemble a pump motor, we needed to hold the  
rotor in order to remove the broken impeller, so we pulled the stator  
off to get access to the rotor. We had to remove the centrifugal lever  
assembly from the shaft in order to remove the stator. We remover the  
broken impeller and reassembled the motor. Reinstalled the centrifugal
lever assembly and the switch the it operates.

  Now at power up the motor just hums.
The rotor spins freely.

We didn't unhook any wires, just pulled the stator off to get access to  
the rotor. I marked the end plate and stator and put it back together
the same way.

Any ideas, why the motor hums.

I want to understand the operation of the motor.

First I'm aware of motors with a start winding, it is energized until
the motor spins fast enough to move the centrifugal lever assembly which  
open the switch to de-energize the start winding.

On this motor the centrifugal lever assembly CLOSES a switch when it  
gets up to speed. Opposite of what I thought would happen. The motor has  
a start capacitor and another part I'm I not aware what it is.
   Here is a picture of the same type motor. In the picture the wrench
is causing the centrifugal lever to swing and open the switch, it can't  
be seen well in the picture.
  Also the black part with three wires, white, yellow, and blue, what is  
it's function.

                               Thanks for your help,

Posted by amdx on July 24, 2014, 5:33 pm
On 7/24/2014 12:10 PM, amdx wrote:

  I think I have found the problem, not sure what I need to do to fix it,
but it will become clear.
This website,

indicates the switch is held CLOSED by the centrifugal lever, and opens  
when rotated fast enough.
  I have it assembled so the switch is OPEN and CLOSES when at speed.
So either I reassembled the lever wrong or reinstalled it wrong, but
I think I have a handle on it now.

Posted by Baron on July 24, 2014, 6:43 pm
 amdx prodded the keyboard



The centrifugal switch always breaks the starting circuit when the
motor is almost upto speed and the other device looks like an
overheat/thermal switch.  It should disconnect the power when it gets
hot enough to trip.  Sometimes they self reset others have to be
reset manually.

Best Regards:

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