Understanding Washing Machine/AC Motors

[launderess]

Was doing some research on the web and came across the article linked below. It is about three-phase A.C. motor drives & controllers for washing machines, and thought some techies in the group might appreciate a good read.

As for Moi, it's all Greek to me, and now off to take some aspirin as reading and trying to understand the darn thing gave me a headache. *LOL*

Launderess

http://www.appliancemagazine.com/ae/editorial.php?article=58&zone=215&first=1

 

[tolivac]

Very interesting link-could understand what was said.However-a couple tyhings I could pick at--The author states the universal motors are more expensive than Split phase induction ones-wrong.Usually in laundy equipment-universal motors aren't used.However in "cheap" contractor style table saws-they have a geared down universal motor turning the blade in place of the induction motor belted to the blade arbor.In some of these cheap machines its just a portable electric circular handsaw mounted in the table trunnion.In the power tools the induction motor is more expensive.also he mentioned split phase cap start motors less expensive than three phase ones-again wrong-thats the big advantage of the 3 phase motor-cost--it doesn't need extra equipment such as start windings and start caps.They are self-starting-making them ideal for the solid state VFD and inverter drives.For a household washer or even power tool-the VFD or inverter can convert the 120V to three phase.Industrial wood shaper-router motors have been run from inverters for years.-to get the very high speeds these tools need.Very good article otherwise.The electronic drivve cas replace some hi-to lo belting or gearing(tumbler washer agitate speeds)to spin speeds.The washer could shift "gears" instantly.-and ramp to the spin speed safely.

 

[launderess]

Universal Motors in Washing Machines

The new Maytag Neptune Compact washer has a universal motor, but the SQ front loaders have a variable induction motors.

Thanks for a great response by the way, but these sort of things still give me a headache! *LOL* But from a consumer point of view, it is good for me to learn so when shopping for a washer, will know if someone is trying so snooker me .

Launderess

 

[tolivac]

Neptune Motors

I thought the Neptune washers had a Permenent Magnet DC drive motor(tumbler washer). Neptune owners should know-correct me if I am wrong.The perm magnet motor is diffrent from the "universal" motor-the universal motor can run from AC or DC power-the perm magnet motor is for DC only.The motor driver board in the machine rectifies the line voltage and varies it to the motor depending on what you want it to do-IE lower voltage for the agitate cycle and higher voltage for the spins cycle.I like the VFD and inverter technology-opens a new world for motor contrrol in appliances and industry.The drives are now becoming much less expensive.Thats a good reason they are appearing in home appliances.They used to be found only in industrial equipment.

 

[launderess]

According to the sales information for the new Maytag Neptune Compact Washer, which is built by Samsung, the motor is universal. Do not know what sort of motor the other Neptune washers have, that is the ones Maytag builds itself.

L

 

[tolivac]

Samsung Maytag

Very interesting-Wonder how the machine sounds-Geared down universal motors can be very NOISEY.Also brush wear would be a concern.A geared down universal motor thats quiet is VERY expensive.Hope the wSamsung machine has high quality gears or belts.Usually cog belts are used-similar to whats in vacuum power nozzles.I am wondering if the machine has cog type belts in it.Would be intersting to see and hear it going.The only laundry product to use such a motor.

 

[jetcone]

Neptune Switched Reluctance

Hi tolivac: Just opened my Neptune service manual. My MAH3000 uses a switched reluctance motor and the stator is wound for 3 phase which is supplied by the motor board by changing 120V ac to 170V DC and then swtiching the current around the 3poles of the stator. The rotor is attracted to the stator poles but the magnetic field is swithced ahead just as the rotor catches up.

Don't VFD drives employ AC? Or PW Modulation and vary the voltage to vary the speed?

jet

 

[tolivac]

Switch reluctance motors

They are starting to slowly sorround us-I just added a Rainbow E2 vacuum cleaner to my collection-It Has a SR Type motor.Rainbow calls it their "Hurricane Force" motor.The vac has two speeds-a very slow speed-the vac can then be used as a room air purifier.Then has a High speed you use for vacuuming.Other vacuums use the SR motor-Meile has a canister-they call it the "Vortex" motor.Dyson has a bagless canister vac sold only in Japan-that has an SR motor that spins up to 100,000 RPM.It has a speaker added to it-If the user has a problem with the vac-They call a service #.Then they hold to phone to the vac speaker-It emits tones representing digital code that tells the service center the model#,SN#,Date unit was built and a trouble code.Than the service center tells the user to send in the machine or how to fix it.I put a link that goes to the manufatorer of the Maytag SR motor.From their pictuer of it on the Maytag washer chassis-shows the motor on the back direct connected to the tub.The site shows other uses of the motors they make.They use them in all types of appliances and equipment-note the manufacturer-it is owned by Emerson electric-largest maker of motors of all types.From what I can tell of the motor-it works on pulses generated by the inveretor to make it turn.A position indicator tells the microprocessor circuit where the rotor is and how to pulse the stator windings to make it turn.From the descriptions the pulse rate determines speed and width seems to determine torque.Just typing "sr motor" gave me all kinds of sites telling how they work and where they are used.The Rainbow,Meile,Dyson motors were designed,built,and implemented by their design staff.Seems like the motor invention of the 21st century!!

http://srdrives.com/frindexhtm

 

[tolivac]

New SR Link to try

Tried my own link and it didn't work.this is the website of the SR motor builder and designer--http://www.srdrives.com/index3.htm
I put this in the link to see if it works.

http://www.srdrives.com/index3.htm

 

[jetcone]

Fascinating Link

Thanks for the link Tol I am trying to develop an advanced electronic program and integrating it onto an old Westinghouse FL as an experiment.

jet

 

[tolivac]

Jetcone-VFD drives

The VFD drive is used with 3 phase induction motors.Its a different animal as compared to the SR motor. the SR motor controller is completely diffrent as the website points out.The VFD drive means "Varible Frequency Drive" it does use Pulse modulation of a higher frequency "carrier" tone-The switching carrier is like around 40-70Khz.It is modulated with the frequency you want to run the motor at.A low pass filter in the drive fliters out the carrier and leaves the AC signal to run the motor.I did watch a Gramm VFD-it was controlling a 100Hp 480V 3 Ph 1750 rpm pump motor for a building chilled water AC system.The motor was running a pump for circulating the chilled water to the air handlers in the building.A readout on the drive tells you the frequency fed to the motor. It could change instantly -and the motor speed would change-you could hear the motor shift speeds-was interesting.Most of the time the motor was running at a lower frequency(less the 60Hz)with thoughts of it using less energy.-The demand for the water was reduced at that time.The power device used in VFD'sis the Insulated Gate BiPolar Power Transister.The device is in a package about the size of a cigareette pack.It could control about 100A of power.These devices are also used in Hi power Shortwave transmitter modulators.They impress the audio program material onto the HV fed to the plate circuit of the transmitters final RF amp stage.I use such a Tx here.What sort of device are you going to use in your Westy washer?-sounds fascinating-A merge with New and Vintage technology!!

 

[westytoploader]

Wow Jon, very cool idea! Hope it works! The best of both worlds--the flexibility of electronic controls with the splashiness of the Westy!

Good luck!

--Austin

 

[foraloysius]

Hey Jon,

I think you are getting in the direction of a "Volkswaschvollautomat"!

Louis