Drain motor for Whirlpool WDF750SAYW0.
 

My dishwasher isn't draining. The drain lines are clean. I removed the drain
pump motor and the first thing I noticed was that when you begin to turn it
by hand, there is a lot of resistance from what feels like a magnetic force.
Then when you continue turning it by hand and overcome the magnetic
resistance, it pops into its next neutral position, sort of like when you
turn a crankshaft on a gas engine by hand and the resistance of the lifters
gives way on the other side of the cam lobe. When I powered it up on the
bench, the motor shakes quite a bit. What would cause a failure like this?

Thanks for your replies.
--
David Farber
Los Osos, CA

Drain motor for Whirlpool WDF750SAYW0.
 

David Farber wrote:

My dishwasher isn't draining. The drain lines are clean. I removed the drain
pump motor and the first thing I noticed was that when you begin to turn it
by hand, there is a lot of resistance from what feels like a magnetic force.
Then when you continue turning it by hand and overcome the magnetic
resistance, it pops into its next neutral position, sort of like when you
turn a crankshaft on a gas engine by hand and the resistance of the lifters
gives way on the other side of the cam lobe.


** That is normal.

The rotor is a magnet, deliberately used in an asymmetric arrangement with the stator.

When I powered it up on the
bench, the motor shakes quite a bit.

** But does it turn ?

I found a rubber band stuck inside one that stopped it turning under its on power. You need to take a look.



...... Phil

Drain motor for Whirlpool WDF750SAYW0.
 

Phil Allison wrote:
David Farber wrote:

My dishwasher isn't draining. The drain lines are clean. I removed
the drain pump motor and the first thing I noticed was that when you
begin to turn it by hand, there is a lot of resistance from what
feels like a magnetic force. Then when you continue turning it by
hand and overcome the magnetic resistance, it pops into its next
neutral position, sort of like when you turn a crankshaft on a gas
engine by hand and the resistance of the lifters gives way on the
other side of the cam lobe.


** That is normal.

The rotor is a magnet, deliberately used in an asymmetric
arrangement with the stator.

When I powered it up on the
bench, the motor shakes quite a bit.

** But does it turn ?

I found a rubber band stuck inside one that stopped it turning under
its on power. You need to take a look.



..... Phil

The motor does turn but it vibrates above and beyond any motor I've ever
encountered. (It would be great if you installed in one of those chairs that
give you a back massage.) The explanation in this video,
https://www.youtube.com/watch?v=M0W9pzBZ-DI says the motor should have a DC
input resistance of 200 ohms. Though I can understand there will be
variances between every motor, this motor measures 20 ohms between the input
terminals. The line draw as registered by my Sencore PR57 is just under 100
watts at 120VAC. The sticker on the motor says 40W.

Thanks for your reply.
--
David Farber
Los Osos, CA

Drain motor for Whirlpool WDF750SAYW0.
 

David Farber wrote:
Phil Allison wrote:



** That is normal.

The rotor is a magnet, deliberately used in an asymmetric
arrangement with the stator.

When I powered it up on the
bench, the motor shakes quite a bit.

** But does it turn ?

I found a rubber band stuck inside one that stopped it turning under
its on power. You need to take a look.


The motor does turn but it vibrates above and beyond any motor I've ever
encountered. (It would be great if you installed in one of those chairs that
give you a back massage.)


** That is normal - for the reason I just gave you.


The explanation in this video,
https://www.youtube.com/watch?v=M0W9pzBZ-DI says the motor should have a DC
input resistance of 200 ohms.


** The video id from the UK where the AC power is 240V.


Though I can understand there will be
variances between every motor, this motor measures 20 ohms between the input
terminals.


** That is also normal.

The line draw as registered by my Sencore PR57 is just under 100
watts at 120VAC. The sticker on the motor says 40W.


** Your Sencore does not measure true watts as it does not take account of power factor which could easily be 0.5

All the numbers you quote are OK.



..... Phil

Drain motor for Whirlpool WDF750SAYW0.
 

What Phil does not understand is how label requirements work in the US. If the motor is labeled "40W", then the maximum free turning running (not starting) load should not exceed 40W, full stop. That part will have a UR label and manufacturers use the nameplate rating to calculate, in turn the entire draw of the appliance for its label. Imagine if any random part might pull a constant 2.2 x its rating on a whim?

If it is pulling 100 watts, and if it is vibrating, then it is clearly damaged and should be replaced. Even low-quality appliances such as most Whirlpool products are, typically, would not tolerate a vibrating motor in that application. I suspect that a motor bearing has gone oval. So the shaft is vibrating against the housing when it spins and starting is very hard, if at all

Again, replace it.

Peter Wieck
Melrose Park, PA

Drain motor for Whirlpool WDF750SAYW0.
 

Drain motor for Whirlpool WDF750SAYW0.
 

peter wrote:

What Phil does not understand is how label requirements work in the US.
If the motor is labeled "40W", then the maximum free turning running (not starting) load should not exceed 40W, full stop. That part will have a UR label and manufacturers use the nameplate rating to calculate, in turn the entire draw of the appliance for its label. Imagine if any random part might pull a constant 2.2 x its rating on a whim?

If it is pulling 100 watts,


** WRONG!!


and if it is vibrating,

** Completely normal.

The Wieck ****wit has never seen a modern washing machine pump.

Or even read my post that explains it all.

What a nasty old ****head.


...... Phil

Drain motor for Whirlpool WDF750SAYW0.
 

Off your meds, again?

I have seen several dozen, as it happens.
This is a dishwasher.
A properly installed pump dishwasher pump will barely vibrate.
Your explanations are not much short of idiotic, but are certainly dead-wrong.

Peter Wieck
Melrose Park, PA

Drain motor for Whirlpool WDF750SAYW0.
 

peter ****wit the LAIR

the cutn has snipped everhting out of sight so he can LIE about it.


I have seen several dozen, as it happens.
This is a dishwasher.

** Same kind of pumps are used - ****head.


A properly installed pump dishwasher pump will barely vibrate.


** Modern examples do, if you hold one in you hand like the OP did.

The rotors are not magnetically balanced like earlier types.

Your explanations are not much short of idiotic,



** My post was 100% correct - you ****ing LIAR.

The OP got himself a proper watt meter a posted the correct numbers.

Drop dead ASAP you psycho, old pig.



..... Phil

Drain motor for Whirlpool WDF750SAYW0.
 

Phil Allison wrote:
peter ****wit the LAIR

the cutn has snipped everhting out of sight so he can LIE about it.


I have seen several dozen, as it happens.
This is a dishwasher.

** Same kind of pumps are used - ****head.


A properly installed pump dishwasher pump will barely vibrate.


** Modern examples do, if you hold one in you hand like the OP did.

The rotors are not magnetically balanced like earlier types.

Your explanations are not much short of idiotic,



** My post was 100% correct - you ****ing LIAR.

The OP got himself a proper watt meter a posted the correct numbers.

Drop dead ASAP you psycho, old pig.



.... Phil

Hi Friends,

I received the new drain pump and tested it first. It seemed to wobble a bit
as it began to spin up, but once it reached full speed, it was very smooth.
The power meter read 13 watts. I put a little pressure on the front of the
impeller and it did not slow down at all. I installed it and all is good
again.

I then disassembled the old pump just to have a look inside. I was expecting
it would not come apart very easily. I was wrong. I put two screwdrivers on
opposite sides of the impeller, used them as levers, and it popped right
out. Here is a photo of the old pump.
http://webpages.charter.net/mrfixite...Drain-pump.jpg

Thanks for all your help.
--
David Farber
Los Osos, CA