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Author Topic: Circulation motor surging (dishwasher)  (Read 365 times)

Offline UTRelectrical

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  • Member Since: Jul 2020
  • Posts: 8
Circulation motor surging (dishwasher)
« on: November 01, 2020, 12:09:04 AM »

Hi, I have a KitchenAid (Whirlpool) dishwasher model KUDE40FXSS5 (February of 2012) not circulating wash water properly.

Permanent magnet motor (WPW10328226) runs in 1 sec. spurts. Ramps up to 123v, then subsides, then repeat. Ohms out good (5-10 ohms per stator pair), control boards are all visually good. Suspected speed/Hall sensor on motor, or wiring harness break, or control board malfunction. Donít see a Hall sensor anywhere, control board looks fine, and wiring harness ohms out as good.

Self Diagnostic Test ran through, indicated wash motor problem. ~5v DC getting to motor control connector.

Wasnít able to bench test motor, but since it runs when 120v applied by control board, I assume itís good, but Control Board is bad (W10473198 - Whirlpool Dishwasher Electronic Control Board).

Iím a little stumped as to why the voltage ramps up and down like that, and hate to buy a $150 board only to discover it doesnít fix the problem. Thoughts?

Offline Dash

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  • Member Since: Sep 2015
  • Posts: 103
Re: Circulation motor surging (dishwasher)
« Reply #1 on: November 03, 2020, 09:52:29 PM »
"New style" Whirlpool dishwashers have lots of false starts; motor will run for one second, pause 4 seconds, run 1 second, pause 4 second, run 1 second, pause 4 seconds, and then finally run.  You can bench test the motor but simply connecting 120V to the motor terminals.  Also, manually check the motor shaft for side play.  No side play in motor shaft is acceptable.

You can test the motor in situ by using a test cord.  A test cord is simply a short extension cord with a male end and in place of the female end, two alligator clips.  Unplug the dishwasher motor wires and attach the alligator clips of your test wire to the terminals. 

FYI, I change lots and lots of motors and computers on the "new style" Whirlpool dishwashers.

Offline UTRelectrical

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Re: Circulation motor surging (dishwasher)
« Reply #2 on: November 03, 2020, 11:37:08 PM »
Thanks for the reply and the insight Dash. All the best to you!

Offline UTRelectrical

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  • Member Since: Jul 2020
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Re: Circulation motor surging (dishwasher)
« Reply #3 on: November 05, 2020, 10:17:57 PM »
I put a new control board in today. Unfortunately nothing changed. Still the little spurting wash pump.

Itís so baffling that the motor runs in spurts, but wonít run continuously.

I even tried bench testing it as suggested, but it didnít do anything... at all. I even double, triple, quadruple checked that full 120v was getting to the alligator clips, and that the clips were on the boardís contact points that the two 120v power wires connect to. Itís all so odd and baffling. The only thing left that it could be, is the motor. Most likely something on the motorsí PCB.

Is there a hall sensor on this motor? I canít tell.

Is there a Service Manual for this dishwasher? I could only find a similar one.

Offline Dash

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  • Member Since: Sep 2015
  • Posts: 103
Re: Circulation motor surging (dishwasher)
« Reply #4 on: November 17, 2020, 08:21:02 PM »
Your motor is bad if it didn't run when you bench tested it.  Connect motor to 120V and it should run full speed without no pauses.  It's a simple motor with no feedback to the computer and no hall effect sensor.

Offline UTRelectrical

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  • Member Since: Jul 2020
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Re: Circulation motor surging (dishwasher)
« Reply #5 on: November 17, 2020, 09:44:00 PM »
Thanks for the insight Dash!

I managed to find a used motor today, so weíll see what happens next.

Offline UTRelectrical

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  • Member Since: Jul 2020
  • Posts: 8
Re: Circulation motor surging (dishwasher)
« Reply #6 on: November 22, 2020, 09:57:38 PM »
Still no luck. New (used) motor does the same as the original motor (runs in 1 second spurts).  I even tried swapping the optical soil sensor, and disconnecting the secondary (smaller 3 grey wires) harness to troubleshoot. When the grey-wire harness is disconnected, it doesnít run at all.

Unfortunately the information in the (similar model) Tech Sheet W10914073A I downloaded from this site does not quite match the required information that I need for this control board model W10473198, so itís missing code explanations (4-1 code), and it talks about 3-phase motor tests, which this doesnít appear to be since there are only two power wires to this modelís motor (but three power wires to other KitchenAid dishwasher motors I have in the shop repair queue.

Unless... that's what the 3 grey wires, and on-board PCB circuit board are for?? To convert the single phase power to 3-phase power for the motor? If so, why do some models use two (blue) power wires, while other models use three??