Thread Number: 11492
The Physics of the Spin Speed
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Post# 205899   4/23/2007 at 22:41 (4,349 days old) by bingwsguy (Binghamton NY)        

Recent machines have an extended spin in the final spin portion of the cycle suggesting less residual moisture. While not a physics major, it seems logical to me that the faster the tub spins and the larger the tub is, the more water removed from the clothing by pure force. The longer it spins at the same RPM should have little, if any impact.
Anyone care to comment?

Post# 205901 , Reply# 1   4/23/2007 at 22:51 (4,349 days old) by dadoes (TX, U.S. of A.)        

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I think more time does have an effect, even at a constant RPM, up to a point. A load being spun is a layer of multiple items so moisture must travel from inside to outside of the layer to exit through the basket perfs. I've noticed running a couple loads in the MiniBasket in Austin's FilterFlo that there were water drops coming out of it to the end of spin. Of course, given sufficient time at a constant speed, extraction will hit a maximum.

Post# 205902 , Reply# 2   4/23/2007 at 23:06 (4,349 days old) by unimatic1140 (Minneapolis)        

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I spun towels out in the Super Unimatic at 1140rpm (with a clear glass window in the cabinet to see the water droplets coming out of the tub). I wondered how long it would take for the stream of water coming out of the towles to stop. After 30 minutes I gave up as water was still being removed from the towels.

Post# 205906 , Reply# 3   4/23/2007 at 23:51 (4,349 days old) by soapnsuds ()        

Hi Robert,

Cool! I'd love to see that on video! ;)


Post# 205926 , Reply# 4   4/24/2007 at 04:04 (4,349 days old) by frigilux (The Minnesota Prairie)        

My 2006 TL Frigidaire has a 12-minute final spin on the Whites cycle. Both the Colors and Delicates cycles have a 3-minute final spin time. While the maximum spin speed on the machine is relatively slow---I'm guessing it's around 500-525 rpm---there is noticeably less water left in the clothes after the long spin on the Whites cycle.

There is also a 20-second spray rinse near the beginning of the final spin, so on the Colors and Delicates cycles you're only getting about 2-1/2 minutes of spin time.

I often use my frontloader as an extractor after washing heavy cotton items (such as bath towels or loads of jeans) in the TL. Quite a bit more water is extracted at its 1000 rpm final spin speed, even after the TL'ers 12-minute spin.

I'd have to concur that a longer spin time removes a bit more water, but that the real bang-for-the-buck in that department comes from substantially increasing the rpms.

Post# 205932 , Reply# 5   4/24/2007 at 05:34 (4,349 days old) by panthera (Rocky Mountains)        
its not how fast you do it (alone) but how you do it

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Several years back, when the 1200 RPM machines were only just becoming affordable, Stiftung Warentest (like Consumer Reports used to be only even more deadly dull) was very surprised to discover that several AEGs running at only 750-900 rpm had equal or better water extraction when compared to the 1200rpm machines.
The way the spin cycle is set up has a big influence on how well water is extracted. A few years later, AEGs running at 1200rpm but still using the excellent spin set-up, vastly outdid all the other machines running at the same speed.
Sure, the higher the speed, the better the extraction. But you have to give that higher speed the time and the well balanced load to do its work. I wouldn't trust a machine to really spin clothes drier just because it has a theoretical top speed of 1200rpm+. Look at the modern junk Bauknecht is putting out and compare it to Miele or B/S/H or Electrolux spinning at the same speed. Big difference in extraction.

Post# 205935 , Reply# 6   4/24/2007 at 05:50 (4,349 days old) by lederstiefel1 ()        
Bauknecht junk

Bauknecht was once a very reliable company until Whirlpool took them over......


Post# 205947 , Reply# 7   4/24/2007 at 06:56 (4,349 days old) by toggleswitch (New York City, NY)        

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Let us also not forget that the diameter of the spinner influences the efficiency of extraction.

Given the same spin-speed a larger tub will generate greater G-force and extract better.

A simple way to demonstrate this is a mini-basket in a GE Filter-flo, which spins at the same speed as the full-sized tub. Mini-basket items tend to stay nearly dripping wet even after a long spin.

Post# 205948 , Reply# 8   4/24/2007 at 06:57 (4,349 days old) by toggleswitch (New York City, NY)        

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~Bauknecht was once a very reliable company until Whirlpool took them over......

So was Maytag.

Post# 205984 , Reply# 9   4/24/2007 at 11:22 (4,349 days old) by johnb300m (Chicago)        

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Maytag screwed themselves. Ironically, Whirlpool will be a needed improvement from independant Maytag.

Post# 205994 , Reply# 10   4/24/2007 at 12:54 (4,349 days old) by jetcone (Schenectady-Home of Calrods,Monitor Tops,Toroid Transformers)        
Actually there are 4 things affecting Extraction

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So everybody has part of the story.
1) One is the tub diameter , a larger diameter and lower speed will produce the same amount of "g' force as a small tub with a higher spin speed.
2) Spin Speed
3) Duration as Robert's experiment proved. There would come a point where the extraction would drop to ZERO but then at the speed he's wailing things around you would start to dry the clothes due to evaporation of the air mass swirling around
4) the forth element is the electrostatic attraction a water molecule has to the fiber it is attached too. Eventually only evaporation will remove this no matter how long you spin or how fast.
Actually there maybe a 5th, the hole size like Glenn mentioned, giving access to the water leaving the tub.
So machines can come in all kinds of configurations to produce a certain g force.
I always wanted to build a top loader spinner that sealed up at the end and turned on a microwave to heat the clothes while spinning and see just how dry they got then!! That would be a cool experiment to try!!

Post# 206015 , Reply# 11   4/24/2007 at 14:57 (4,349 days old) by soapnsuds ()        
Hi Jetcone,

~~1) One is the tub diameter , a larger diameter and lower speed will produce the same amount of "g' force as a small tub with a higher spin speed.~~~

So what does this mean exactly? That my Asko which spins at 1600 RPM's extracts the same amount of water as my LG which tops out at 1100 RPM's?

What about the weight or size of the load? Does a full load of towels help with the spin and extract more water because there is more weight or does it hurt because there are more layers for the water to go through before it leaves the tub?

And while we're at it, how DOES a solid tub washer extract water without holes? I realize that in the begining the water is thrown over the top, but after a certain point, there isn't anymore to throw over...seems to me, when the cycle is done, you'd be left with a wall of water on the inside of the tub.

These are the burning questions of the day!!


Post# 206020 , Reply# 12   4/24/2007 at 15:45 (4,349 days old) by jetcone (Schenectady-Home of Calrods,Monitor Tops,Toroid Transformers)        

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Let me get back to you later, I must walk AL now its HIS time!


Post# 206021 , Reply# 13   4/24/2007 at 15:47 (4,349 days old) by roto204 (Tucson, AZ)        
Squidge factor

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Part of the reason a solid tub works is that there actually are holes tucked up under the top lip of the tub.

That notwithstanding, when you accelerate the tub, the water flattens out to cover the surface area to which it's "squished." Since water is a liquid and tries to take the shape of its container, it flattens continually until it squirts out the holes at the top, or flies up over the top edge of the tub.

That's why there isn't any water to speak of left after a solid-tub spin. If the spin were perfectly balanced, slow, and the tub was mostly closed, like a doughnut, then I could see where you'd just end up with a ring of water on the inside. But the design of the tub and the physics at hand take care of business :-)

Post# 206033 , Reply# 14   4/24/2007 at 16:50 (4,349 days old) by chestermikeuk (Rainhill *Home of the RailwayTrials* Merseyside,UK)        

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The fifth is not the hole size but the configuration of water leaving the tub...The UK Servis Quartz Front Loaders of the late 70`s had a "SpinCare" drum, no holes just a bevelled drum with a channel at the back , front & Middle, so the water was channeled to the vanes and extracted...

Most uk manufacturers used to advise no more than 4 mins for max extract of cottons from a twinny spinner running at 2,800 / 3,100 rpm..

We also had a "Thermair" spinner in the 60`s that had a heater on top situated in the lid, and blowed warm air down onto the clothes...was popular but didnt last long, if you didnt shake out the clothes before heating they would crease badly from being plastered against the side etc...innovative though...


Post# 206058 , Reply# 15   4/24/2007 at 20:29 (4,348 days old) by toggleswitch (New York City, NY)        

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~That my Asko which spins at 1600 RPM's extracts the same amount of water as my LG which tops out at 1100 RPM's?

Assuming the Asko's cylinder is 22" in diameter to fit in a 24" cabinet, and that the LG's cylinder is 25" in diameter to fit in 27" cabinet, then: both spinning at 1,100 RPMs would make the LG more effective. It is possible that at 1,600 rpm the Asko is extracting the same or slightly more (but not a lot more) than the LG due to the Asko's smaller cylinder.

Let's put it this way, Euro washers must spin fater than American ones to extract the same amount of water. Sometimes bigger IS better. Euro dryers have 2,500w +/- heaters (plug-and-play into any power-point) whereas American dryers have 5,000w heaters (special 30a 220v circuit). Again this demands greater extraction ont he part of Euro washers as well. Excessive extraction, however, can be said to tear fibers in the clothing and to cause excessive creasing / wrinkling in and of itself.

Please note, I did not say or imply one system is better than or preferred to the other.

Post# 206130 , Reply# 16   4/25/2007 at 01:04 (4,348 days old) by panthera (Rocky Mountains)        
bigger is always better,

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And the only two US appliances I miss in Europe are dryers and refrigerators.
I've spin dried stuff at 2,800 for over 24 years now...never lost anything into near-earth-orbit yet...but also never ran longer than five minutes.
At 1200-1800 rpm, absolutely no chance of tearing or permanent wrinkling...else they would not be accepted by the testing societies here in Europe or the very clothes conscious.
I adore the way you tip-toed around the split-phase current. Actually, the UK no longer has 240V...they only have 230V now like the rest of us...

Post# 206177 , Reply# 17   4/25/2007 at 08:38 (4,348 days old) by bingwsguy (Binghamton NY)        
Thanks Everyone

Keven, you brought out another question. The "How you do it" comment made me wonder if the machine picking up speed slowly vs. taking off & going right up to full speed has any effect on extraction?

Mike and Nate you answered questions I had about the size of the holes in the tub....and for that matter none at all. I was under the impression that the more holes, the more water would escape. When Miele came out with the Honeycomb Drum with more surface area and less holes...I wondered about that, but figured if they developed it it must work. I still have questions on the Honeycomb Drum...another thread...

Steve and Robert, thanks for the real-life test feedback on drum size and time...I assumed the size would make a difference, but not the length of time at constant speed.

Post# 206181 , Reply# 18   4/25/2007 at 09:13 (4,348 days old) by soapnsuds ()        
Yes, thank you everyone for all the help!

~Euro dryers have 2,500w +/- heaters (plug-and-play into any power-point) whereas American dryers have 5,000w heaters (special 30a 220v circuit).

What do you mean "plug-and-play?" My ASKO has a 240 volt plug,(and then the washer plugs into the back of the dryer) you mean it's not the same size heater as my LG? I know its probably a bit smaller, because the dryer only has to heat settings, low and normal. And when I read the brochure after I got them the ASKO said that the dryer differed slightly then and american one because Europeans believed in lower heat drying for longer time vs. higher heat for shorter times. Gentler on the fabrics they said. I say higher on the old electric bill. Since I have to heat the hot water in the machine AND dry the towels forever in the dryer. Is there really that small of a heater in the ASKO vs the LG?

As always, thanks for the time and help!! -James

Post# 206186 , Reply# 19   4/25/2007 at 09:39 (4,348 days old) by 48bencix (Sacramento CA)        
Horizontal Axis

I wonder if the front loaders will spin more water out at an equal spin speed. On the down side of the spin, you have the earth's gravity pulling too, an extra one-g.


Post# 206190 , Reply# 20   4/25/2007 at 09:50 (4,348 days old) by lederstiefel1 ()        
European dryers

The thing is that in Europe normally circuits are limited to 20 Amp for normal household use. So to avoid unnecessary costs for an installation of a higher amp outlet which is usually then linked to a higher voltage, namely 400V, and/or an extra three phase rotary current, they cut down the heaters to not more than 3,000W (Miele) or less plus another 500W for fan and motor plus electronic altogether.
We had once 220V/50Hz in Germany but switched to 230V/50Hz some 15/20 years ago! Also there is (in the 50s and 60s very popular) three phase rotary current available for housholds: 380V/50Hz once and 400V/50Hz today. This was very often used in the time when people used to wash with tub-washers in the laundry-rooms in the basements, because of the boiling programmes in these machines, which would have taken ages to heat up otherwise. These machines had often 4.5KW or 6KW or even stronger heaters in them to bring the 60-100 liters of wash-water to the boil in an appropriate time. Still it is in use for hot water tanks (6KW/400V), continious water heaters (18-27KW/400V), night-storage heaters (4-8KW/400V) and even some kitchen ranges have rotary current, but these mostly with 230V.


Post# 206192 , Reply# 21   4/25/2007 at 09:56 (4,348 days old) by chestermikeuk (Rainhill *Home of the RailwayTrials* Merseyside,UK)        
Dryer Times

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I think there is something in the motor torque that drives the spinning basket...I`ve tested induction motors from a number of machines against certain carbon brush motors and I think there is a difference...even with the same drum diameter..

The Asko really DRIVES the drum to spin, you can feel & hear the power or torque as it pushes the revs, a lot of induction motors can do the same spin but almost balance each other out with power..Also the Unimatic, the torque and power you can feel & hear as it drives up to 1140rpm..

There is also more to just heater wattage in a tumble dryer...a few vented UK models ran only on 2kw heater because of the "High Velocity" air-flow....think windy day, no sun, washing still dries...

I think what we have been used to is always going to be an influencing factor over the desire to change to new stuff,and to adapt to the changes also takes time, the modern machines I`m using now are overall the most economical and efficient to date, the only other co-efficient required is lower electricity costs, and I cant see that happening!!!

I`ve included my test results I did for Robert, take a look, Mike

Post# 206279 , Reply# 22   4/25/2007 at 17:24 (4,348 days old) by toggleswitch (New York City, NY)        

toggleswitch's profile picture
~What do you mean "plug-and-play?"

In 220v lands, clothes dryers tend to plug into ANY ordinary outlet. Our electric ones require a dedicated, special heavy-duty line. They genrally tend to be smaller than what we are used to as most appliances in other lands are 24inches (60cm) wide.

In order to ger Euro 220v washers into this counntry without rewiring, they plug-in, piggy-back, into the Euro dryer. This is possible becuase Euro dyrers use only a fraction of the wattage and amerage that ours do. They therefore also take a great deal more time to dry.

The maxiumum load normally permitted yb code here is generally 80% of the wiring's capacity. On a 30a line, then 24a is the max gnerally seen and used. An American dryer uses that much amperage.

Logically then, if a Euro dryer was as powerful, a washer would not be able to share the circuit. A Euro washer and a Euro dryer can share an American 30a electric dryer circuit becaue they are each, lets say, less than 15a. (Most likely 13a or less.)

I am not saying one system is better or worse. What I am saying is that laundry machines and washing preferences evoled in part due to the respective electical systems, construcion techinques and the mentality ("culture") of the inhabitants; good, bad or otherwise.

Also I believe a great number of homes are concrete across the pond which makes running and hiding electrical lines difficult. Here we use a great deal of wood and have hollow walls. Running lines later in time is perhaps easier. Someone please enlighten me!

In this country a Euro washer with an American dryer is a good combination. An Aerican top-loader with a Euro dryer is bound to cause complaints. The dryer is smaller and relatively slow and won't deal well with less extracted water. IIRC some Euero mannies owont sell you a dryer for use with an American washer.

Wanna make big money? Sell gas appliances in Europe ion counrties that are currently being piped for natural gas as a result of a huge contract in the last few years with former USSR republics to supply gas. Large capaity, vented, quick, economical gas dryers. Come on all you Keynsians. Supply creates its own demand!

CLICK HERE TO GO TO toggleswitch's LINK

Post# 206457 , Reply# 23   4/26/2007 at 09:09 (4,347 days old) by soapnsuds ()        
Thansk Toggle...

I wondered how my ASKO washer AND dry was able to run off the one dryer plug at the same time. You're right, the washer piggy-backs into the dryer for power, a fact I like and the main reason I purchased it over Miele, that and ASKO has a spin only option, for whatever reason Miele got ride of theirs years ago. And Miele makes you buy this box for about $200 more for plug-n-play action, as you say, to plug the washer and dryer in, then plug that into the one dryer plug. LOVE Miele (miss mine), but they subscribe to the Sony mentality when it come to accessories...

Thanks everyone for all the great info. I KNEW I should have been an appliance repairman!! MUCH more fun!!! ----James

Post# 206589 , Reply# 24   4/26/2007 at 21:54 (4,346 days old) by toggleswitch (New York City, NY)        
And Miele makes you buy this box for about $200 more for plu

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That price is just highway robbery. You can't possbily tell me that the price is reflective of perceived European quality/engineering. Sounds like good old-fashined snobbery to me.

I'm glad I was able to clarify some things.....
BTW, by "Plug-n-play" I meant that in Europe and the UK any dryer generelly plugs into any outlet.

Post# 207689 , Reply# 25   5/1/2007 at 15:17 (4,342 days old) by coit ()        

As far as I can tell GB's change from 240 to 230 volts is just theoretical acknowledgement of a european standard.
Voltage varies depending on how close to a transformer your house is.
In Australia it is 240 volts but I measure 250 volts RMS at my powerpoints whereas a mate of mine measures less than 230 at his.
So an audio amp will sound louder at my place.

Post# 207722 , Reply# 26   5/1/2007 at 17:53 (4,342 days old) by toggleswitch (New York City, NY)        

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Ditto here.

On Long Island the voltage is nearer the higher end in general, and I am the first house "off" the tranformer....

My cookers' (I have more than one) electrical heat switches for the surface elements are constantly burning out and arcing due to the (excessive) voltage.

On the positive side, my central air-conditioner will still run nicely during a summer brown-out and will be one of the last to shut down during excessive power draw on the electrical grid during a major heat wave.

[Due to chinese-made room air-conditioners at <$100 EVERYBODY who could not afford A/C previously now has at least one, and the grid is NOT happy.]

Post# 209058 , Reply# 27   5/8/2007 at 20:46 (4,334 days old) by sudsmaster (East of SF, West of Eden, California)        
The actual physics of it

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Turns out the rpm's are a much larger influence on G force than the drum diameter. I'll have to chase down the formulae again, but as I recall the G's increase linearly with drum diameter, whereas they increase as a square of the rpm's.

I do know that the Neptune 7500/6500 at 1000 rpm (top speed) geneates about 300 g's.

Other factors influenced water extraction may be the drum design. Specifcally, the inner surfac etne the size ang placement of the holes. I believe Miele claims its honeycomb drum, despite have a smaller overall hole ares, extracts water better than previous drum designs. It's also possible that a solid drum top loader extracts more water and more gently than an equivalent perforated drum top loader.

Post# 209061 , Reply# 28   5/8/2007 at 20:57 (4,334 days old) by sudsmaster (East of SF, West of Eden, California)        
G Force Formula Unmasked

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For a washer, the G-force formula is:


For the Neptune, that's:

1000*1000*21.175/70,500 = 300.35 G's.

If we were to increase the drum diamter by 10%, then the G's would be about 330. If we increase the RPM's by 10%, but leave the drum diameter alone, then the G's would be about 363 G's.

Post# 209096 , Reply# 29   5/8/2007 at 22:03 (4,334 days old) by toggleswitch (New York City, NY)        

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Diameter in inches?

Post# 209104 , Reply# 30   5/8/2007 at 22:34 (4,334 days old) by cybrvanr ()        

I am suprised nobody has mentioned another thing that can come into play, if only sightly. Has anyone ever noticed the wind that comes off of a Top Loader while it's in a good spin cycle? I imagine the air currents that develop while in the spin cycle also contribute to a little bit of drying too. After all, you are moving the clothing at a rather high velocity, so it would be like hanging a shirt out a car window while traveling down the highway.

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