Thread Number: 77941  /  Tag: Modern Automatic Washers
energy 'saving'???
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Post# 1019610   12/31/2018 at 15:30 by rancherman (nebraska)        

I'm not an electrical engineer. Dad was a mechanical engineer.. so I got some 'pearls' of knowledge as I grew up.

I was told early that keeping an electric motor 'on' was much less strain on it, and the starting circuit. 'starting' one consumes a LOT of watts.
He was referring to his machine shop with a lot of 10-50 hp motors running various machines. Lathes, huge press brakes, shears, rollers. Most of these machines would sit running, 'idle' until a lever would engage a load. many ran all day long, until the whistle blew.

Now, when we look at a 1 hp motor, on a modern washing machine that starts, stops, reverses, starts, stops over and over and over...
Or a .5 horse motor doing the SAME load, but continuously runs...
The 1 horse motor 'should' take exactly twice the power (watts) to run? More if the 'starting amps' are figured in too??
Seems backward to go from .5 hp to 1 hp if energy saving is the wanted result.
I suppose the actual power required by the machine includes power to run the motor, control board, and any indicator lights.
Is power to heat the water included on 'energy ratings'? Maybe reducing amount of HOT water per load is where the real measurable savings come from.
Are the new motors 'brushless'? (that is about as deep as I go in the electric world) LOL. I'm an Internal Combustion guy!!
Somewhere in my possession, I have a still working single cylinder Maytag engine.
......kick start, leg breaking marvel... It was my Grandmothers. I still remember her cussing it in German, as she tried to start it!
Ah, just musing over some thoughts... while waiting for my new SQ to be shipped.

Post# 1019672 , Reply# 1   1/1/2019 at 07:57 by arbilab (Ft Worth TX (Ridglea))        

arbilab's profile picture

Small motors draw twice their nameplate 'full load amps' when stalled.  Operating normally, that's on the order of a half second.  If a small motor takes much longer to start than that, it's in trouble and seconds from overtemp cutoff.  At home you pay for Watts x hours.  1 W for 10hrs, 10W for 1 hour, 100W for 6min, all exactly the same.  So the cost of starting the motor is 'measurable' but insignificant.


Industrial motors like you said, drive a flywheel which must be brought up to speed.  Their motors typically have elaborate provisions for startup.  1) so it doesn't strain the motor and 2) since industrial electric rates are scaled to peak kW demand rather than simple W x hours. 


Yes, recent machines tend toward 'brushless'.  Internally they are 3-phase motors and since homes seldom have 3-ph service the motor controller creates the phases.  It can also sense load, reduce power when less is needed, change directions, control speed and acceleration. 


Such motors are not "new" but migrated to home laundry as the designs and parts became 'production' rather than 'custom'.  Like what happened to flatpanel displays; very expensive when first introduced and now around 1/10th~1/20th as much.  Before that, it was cheaper to just throw a plain-old motor in there.  Now, in many applications the improved motor allows the transmission to be much simplified or done away with altogether.

Post# 1019703 , Reply# 2   1/1/2019 at 13:14 by DADoES (TX, U.S. of A.)        

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Fisher & Paykel developed the use of the 3-phase "pancake" direct-drive motor in washers with their SmartDrive design, yes?

I checked the wattage draw with a Kill-a-Watt meter on one of my machines.  There's a gradual increase as spin speed ramps up.
Standby = 4.5 watts.
Control on = 5.4 watts.
Pump running (standard 120v) = 103 watts.
SmartDrive "surge" at spin start = 122 watts.
670 RPM = 242 watts.
1,010 RPM = 328 to 341 watts.

Compared to a WP DD.
685 to 521 watts high spin.
535 to 419 watts low spin.
288 watts low agitate (no water).

Post# 1019723 , Reply# 3   1/1/2019 at 14:56 by Eronie (Flushing Michigan)        

Odd the FnP stator has Whirlpool stamped right on it.

Post# 1019728 , Reply# 4   1/1/2019 at 15:23 by DADoES (TX, U.S. of A.)        

dadoes's profile picture
F&P had a manufacturing facility in Ohio.  The F&P AquaSmart washer to which the motor belongs was produced there per its serial number June 2009.  Whirlpool used/uses SmartDrive motor components on their Oasis, Cabrio, and Bravos models.

Post# 1019780 , Reply# 5   1/2/2019 at 00:15 by tolivac (greenville nc)        

The FP direct drive washer motor is like a DD Technics TT motor.3Ph commercial industrial motors-Yes,they do consume while running-most times they are used the motor runs ONLY when needed.Idle running motors-esp no load present a low PF load to the utility-this is not good just dealing with the no load inductive loads-raises issues of power factor to the utility and possibly other customers.This is why you see banks of capacitors on poles or in power company substations.The caps are switched in by time of PF loading.This also applies to idle energized transformers with no load on them.Utilities and customers don't like paying for "magnetizing" of transformer and motor cores.3Ph motors are self starting-no start windings or caps needed.And simple to reverse-just reverse one phase.Some power companies hyave restrictions on motors started under load-such as compressors-so Wye-Delta starters are used.Wye starts draw less power.

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