Thread Number: 72030  /  Tag: Modern Dishwashers
What type of motor do these use?
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Post# 952660   8/12/2017 at 12:37 by chetlaham (United States)        

Do these use an induction, synchronous, inverter or DC motor? I can't figure it out, but I am going to be honest with everyone here. After the "cake" thread I am starting to get this urge to play with one of these:

I figure now that the technology was had several years to mature and that many engineering changes and models latter have produced a bug free product.

Here is the motor that the internet gives:

Also, does anyone know of the wash and rinse temperature on Heavy + High temp?

Post# 952662 , Reply# 1   8/12/2017 at 13:19 by henene4 (Germany)        

According to the manual, Heavy\High Temp uses almost 40l/10gal and only runs ~150min.

That shoud be a single speed machine, so nothing fancy. So no DC or inverter I'd say.

Post# 952664 , Reply# 2   8/12/2017 at 13:28 by chetlaham (United States)        
10 gallons

Now thats my type of machine :)

So you would say just a synchronous AC motor? I ask because at one point BOL Frigidaire machines had a giant circuit board in the motor.

Post# 952668 , Reply# 3   8/12/2017 at 14:52 by Rolls_rapide (Scotland, UK)        

rolls_rapide's profile picture
That is appears to be an alternating current magnetic pump. Basically a slightly bigger version of the typical magnetic drain pumps fitted to every make and model under the sun.

Post# 952669 , Reply# 4   8/12/2017 at 15:33 by henene4 (Germany)        
Boards on motors

True inverters usually require some form of advanced cooling, usually a heat sink. AC to DC rectifiers do not, however they need some form of switching or the good old brushed commutator system, which is way chunkiert than that pump. So yeah, some for of induction or more likely a synchronus motor (wich basicly is what most drain pumps are).

Post# 952679 , Reply# 5   8/12/2017 at 17:10 by chetlaham (United States)        

So its just coils of wire then? I can dig that :)

What about the high end Whirlpools? Aren't those motors inverter or something? The pump looks different on those.

Post# 952680 , Reply# 6   8/12/2017 at 17:16 by cfz2882 (Belle Fourche,SD)        

looks like a synchronous motor with bi-directional pump.I saw one synchronous dishwasher main pump,~1998 vintage,that had a circuit board built in to make the motor run the same direction every time-allowing a more efficient directional pump to be used.

Post# 952682 , Reply# 7   8/12/2017 at 17:31 by gansky1 (Omaha, The Home of the TV Dinner!)        
HD reviews aren't great

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My mother has this d/w in her new apartment. A bit noisy, no rinse-aid dispenser and marginal cleaning. If you're a pre-rinser and have a stack of dish towels handy, this is your machine.

Post# 952683 , Reply# 8   8/12/2017 at 18:32 by cuffs054 (GA)        

If I'm going to spend $150+ and go through having to pull the whole mess out, l'm just going to bite the bullet and replace the machine.

Post# 952694 , Reply# 9   8/12/2017 at 22:57 by combo52 (Beltsville,Md)        
Pull The Whole Mess Out?

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These and all WP DWs can have the motor removed and replaced without removing the DW from the installed position.

Post# 952709 , Reply# 10   8/13/2017 at 06:46 by chetlaham (United States)        
A better make

Is there a better make in terms of cleanability? My understanding is that they all use the same mechanism. I can live without rinse-aid. My rinse-aid dispenser at home is still empty lol, never been filled.

Post# 952710 , Reply# 11   8/13/2017 at 06:49 by chetlaham (United States)        

@cfz2882: Never new such a motor existed having a board to force only one direction. Anyone know if this motor is such? Better yet, Combo, do you have any replaced (to be scraped) motors lying around? I'm really curious how these new DW work.

Post# 952721 , Reply# 12   8/13/2017 at 09:11 by combo52 (Beltsville,Md)        
Main Motors in WP Built DWs Since 2000

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WP has used more than a 1/2 dozen different main motors and another 1/2 dozen different drain pumps as well in their DWs in the last 17 years or so.


WP has generally built the best cleaning, best drying DWs over the last 50 years or more, and by far about the most easy to repair 99% of the time without having to remove the machine from its installed position.


Hi Chet, yes we have lots of motors lying around that fit these newer DWs, if you are ever interested you are very welcome to visit and go through them and even take some home. The motors WP is using seem to be quite reliable and we have little demand for them as used motors so a lot of them just go in the recycling bin unlike the crappy brush type motors that FD have used for the last decade + and now GE seems to be using these low durability in their newer DWs as well.


John L.

Post# 952726 , Reply# 13   8/13/2017 at 10:19 by chetlaham (United States)        

Thanks Combo, that means a lot to me :) You are very generous. I might order one or two just to take apart- will see.

I do agree with you about repair. It seems that the most easy to repair by far of any machine be it dryer, washer, DW or range is hands down WP. Their newer vertical modular washer is by far the easiest thing to fix- easier then small appliances and computers if you ask me. Light weight and few sharp edges to.

If WP is using synchronous motors then I think we have a winner. A brush motor does not belong in a DW IMHO. And for the price a BOL whirlpool is giving you 3x more in all categories including longevity.

Drying- this is a biggy for me. I do not use rinse agent, so I rely entirely on what the machine can do. I've had Whirlpool machines that dried very well with and those that needed towels at the end of the dry cycle. If I was to buy a Whirlpool made machine, which would you recommend from drying aspect?

Post# 952763 , Reply# 14   8/13/2017 at 14:15 by henene4 (Germany)        

The best thing I found for drying is just popping it open after a cycle and to wait a few hours. Oh, and it has a heated dry, so that should help, right?

Post# 952821 , Reply# 15   8/14/2017 at 00:32 by tolivac (greenville nc)        

I wouldn't think Whirlpool would be using a Synchronous motor in a dishwasher--Synchronous motors I know of are PRECISION "instruments" for maintaining a precise speed-synchronized to the frequency of the power line feeding it.Thus such a motor is VERY expensive in that size-more likely its an induction motor.The permanent magnet synchronous motor made the small ones possible-but still expensive-found them in record turntables,Hammond organ tone wheel drives,tape recorder capstan drives.The largest one I encountered was for the capstan drive in an Ampex Quad VTR.The motor was driven by a tubed or solid state power amplifier driven by the TV station sync generator.In physical size it is as big as a washer or dishwasher motor.The amp that drove it put out like 700W!

Post# 952864 , Reply# 16   8/14/2017 at 10:19 by henene4 (Germany)        

Synchronous motors are not necessarily expensive. An induction motor running directly from the mains behaves pretty much like a synchronus motor. If you want to speed controll a synchronus motor, you'd need to modify the frequency of your supply, which would require a inverter, which makes it more expensive.

A synchronus motor has permanent magnets on the rotor, the rotation speed is affected by the frequency of the supply. So it's just windings, the alternation of the field is done by mains frequency. Or, for variable speed applications, an inverter alternates the frequency of the incomming supply to match the speed desired.

An induction motor uses inductive effects to create a current in the rotor windings to create the rotors magnetic field. Thus, just like a synchronus motor, it has a synhronus speed.

Post# 952933 , Reply# 17   8/14/2017 at 20:34 by chetlaham (United States)        
Magnet vs Induction

Why would Whirlpool choose an permanent magnet motor over an induction motor?

Post# 952940 , Reply# 18   8/14/2017 at 21:22 by combo52 (Beltsville,Md)        
DW Pump Motors

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Permanent magnet motors cost more to build but use far less power.

Post# 952944 , Reply# 19   8/14/2017 at 22:00 by earthling177 (Boston, MA)        

Induction motors are asynchronous motors -- they run *close* to the speed they'd run if they were *synchronous* motors, but not the same.

For example, a 2-pole synchronous motor runs at precisely 3600 rpm at 60 Hz. A 4-pole sync motor runs at 1800 rpm.

Contrast that with 3450 rpm and 1725 rpm, which are (common) speeds under load for a 2-pole asynchronous (induction) motor and a 4-pole one.

Synchronous motors (particularly vey large [over 10HP] ones) usually cannot self start, particularly under load -- several different ways have been used over the years, like disconnecting the load with clutches, using an auxiliary starter motor, or, more recently, building a self-starting motor (typically induction) that disconnects as the speed gets near synchronous speed and turns the motor into a synchronous motor.

Induction motors are asynchronous because they depend on having a spinning magnetic field to generate the current in the rotor.

There isn't a very good reason to use a synchronous motor, which costs more (usually) to build than other kinds if you are not making use of the main advantage of such motors, which is very precise speed. If you just need variable speeds, there are many cheaper ways to achieve it.

Post# 952956 , Reply# 20   8/15/2017 at 00:20 by tolivac (greenville nc)        

Self start synchronous motors use auxillary windings on the rotor to make it start like an induction motor.As it reaches 75% speed-the field current is applied and then the motor runs as a synchronous one.Small synchronous motors are expensive-those below 10 hp-esp those under 1hp.They are used where the speed is critical.Induction motors won't maintain speed when used for purposes where speed is critical.Induction motors won't reach synchronous speed because of the magnetic "slip" in their design.Yes,older design synchronous motors used "pony motors" for starting.

Post# 952975 , Reply# 21   8/15/2017 at 06:35 by tolivac (greenville nc)        

Another addition for LARGE Synchronous motors-yes they are more efficient than induction and have greater breakdown torque.A bonus-they can be used as a power factor correction device-adjust the DC to overexcite the rotating field and you have a variable power factor correction device.If you see a large cylindrical horizontal object at a substation-it is an enclosed synchronous motor that the power company can start and adjust if the power factor goes out of tolerance.The motor does not drive a mechanical load.It is enclosed in a hydrogen,nitrogen,or SF6 filled container.Modern synchronous motors are brushless-they use a rotating secondary transformer winding on the rotor along with a rotating rectifier assembly.The primary is stationary.This same system is used with synchronous power generators-the one we have works this way.Cat 3816.

Post# 953022 , Reply# 22   8/15/2017 at 14:22 by chetlaham (United States)        

All excellent and very educational replies! :)

Spot on about induction motors never being truly synchronous due to the slip and need for a spinning field to generate a counter field in the rotor. Immediately reminded me of this video:

One advantage to Whirlpool's motors (at least the DW drain pumps) is that they appear to not have any type of rotor seal, ie the rotor is housed in water and the stator slips over the plastic housing.

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