How Much Acceleration Would be Noticed in a Jumping Washing Machine

studiot

Joined Nov 9, 2007
4,998
I do know that the loaded water+clothes+machine weighs about 100kg when starting to dance and wander around.
Are you sure about this with a spinning drum?

You have omitted the gyroscopic force.

Watch here

 

Thread Starter

madsi

Joined Feb 13, 2015
107
Fascinating. So it seems the rotational force of the drum and clothes makes the machine lighter..but it is only the imbalance that make it dance!

I would really like to know why they saw the need to put those two thick (aaprox. 25kg) concrete masses on this dancer?

When I bought this machine it was on sale, it was almost 50% off its ordinary price. It offered a centrifuge max. speed of 1400 rpm and a capacity of 7kg of wash.

After the machine was brought home and put to work, I discovered the hidden talent within this Candy washing machine. At this point I went back to the big discount seller's website and noticed that several people had bought this machine and had written less than favorable reviews, some were outright expressions of regret. This is where I first saw the word dance associated with a washing machine.

One of the attractive features of this washing machine was its large capacity tub. This means large items like sheets can have room to fully enjoy a bath and not shadow each other from the cleansing forces of fast flowing water, the smaller tub preventing the dander from being swept away, as happens with the smaller diameter tub of my previous machine which suffered from CCC, the close clothes crowding effect.

But here's the mystery, I just saw a discarded quality named brand machine(Electrolux) in the large apparatus area of our apt. complex garbage area.

The top was removed for whatever reason, the inner tub enclosure was clearly seen within. There were no large weights! The construction was otherwise the same as my machine with the inner enclosure suspended within and the motor connected to the rotating tub enclosure it was mounted on, a belt driving the large wheel that conveyed the mysterious forces of dance to the washing tub within.

How is it that I could possibly buy a 12kg capacity washing machine just about the same physical size, just about the same tub size and weight, but that can centrifuge at 1800 rpm, and that apparently does not dance? Of course, the price was higher for this machine.

What would happen if I removed the top concrete block from the tub enclosure, leaving the less accessible bottom one? It is only fastened with three large bolts to the fibreglass drum enclosure.
 
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OBW0549

Joined Mar 2, 2015
3,566
I would really like to know why they saw the need to put those two thick (aaprox. 25kg) concrete masses on this dancer?
At this point, I'd conjecture it's because 50kg blocks wouldn't fit, and they hoped (in vain) that 25kg blocks would suffice to keep the poor thing in its assigned position.

What would happen if I removed the top concrete block from the tub enclosure, leaving the less accessible bottom one? It is only fastened with three large bolts to the fibreglass drum enclosure.
I don't know, but I think if you try it you should post a youtube of the result-- it might be dramatic.

Has your accelerometer arrived yet? I'm keen to find out what g forces you measure.
 

studiot

Joined Nov 9, 2007
4,998
The imbalance has a long lever arm so it creates a large moment about the spin axis.

This lifts first one corner then the other with a regular period, due to the spin speed, causing the 'dancing' as a resonance phenomenon.

Yes a more expensive model will be better balanced, have direct drives and/or better bearings, but I expect the electrolux damping weights had been removed before you saw it.
You should not remove yours.

Some machines have alternative spring loaded damping in the drum suspension.
 

Thread Starter

madsi

Joined Feb 13, 2015
107
The imbalance has a long lever arm so it creates a large moment about the spin axis.

This lifts first one corner then the other with a regular period, due to the spin speed, causing the 'dancing' as a resonance phenomenon.

Yes a more expensive model will be better balanced, have direct drives and/or better bearings, but I expect the electrolux damping weights had been removed before you saw it.
You should not remove yours.

Some machines have alternative spring loaded damping in the drum suspension.
Thanks studiot, but..
No, I could see clearly that there were no mountings, no place to fasten a concrete block on the inner tub enclosure.
No, it was not direct drive, the same motor-belt-pulley arrangement.
The bearings are good enough on my machine, ok it was obviously somehow better balanced!
 

Thread Starter

madsi

Joined Feb 13, 2015
107
At this point, I'd conjecture it's because 50kg blocks wouldn't fit, and they hoped (in vain) that 25kg blocks would suffice to keep the poor thing in its assigned position.


I don't know, but I think if you try it you should post a youtube of the result-- it might be dramatic.

Has your accelerometer arrived yet? I'm keen to find out what g forces you measure.
Thanks for your thoughts, OBWO549. This is the first weekday after the weekend and I cannot expect the accelerometer to arrive by helicopter nor drone.
 

Alec_t

Joined Sep 17, 2013
14,280
Some machines have alternative spring loaded damping in the drum suspension.
I used to have one like that (can't remember the brand). The outer drum was mounted to the housing by hefty springs and had a fixed chromed-steel plate which was sandwiched between two sprung brake-shoes to provide frictional damping.
 

#12

Joined Nov 30, 2010
18,224
Regretfully, I agree with joey.
I have seen them all in my 40 years of repair work.
Machines that stop and buzz when out of balance, a machine that did not have its shipping blocks removed :eek:
Computer Aided quality minimization, front loaders that are bolted to the floor...
Do you want to measure it or use it?
 

joeyd999

Joined Jun 6, 2011
5,237
...front loaders that are bolted to the floor...
You misunderstood.

I meant fire the nail gun multiple times into washer. Then call the manufacturer and tell them what a piece of **** it was -- and that you've taken the liberty of humanely putting it out of its misery.
 

#12

Joined Nov 30, 2010
18,224
I use a different approach. I bought a clothes washer about a year ago. After examining every part of it, I ripped out the wiring harness and installed my own design. There is nothing left of the original controls except the motor drive and the fill switch. :)

Here is one of several pages of my modifications:
 

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Thread Starter

madsi

Joined Feb 13, 2015
107
You misunderstood.

I meant fire the nail gun multiple times into washer. Then call the manufacturer and tell them what a piece of **** it was -- and that you've taken the liberty of humanely putting it out of its misery.
Joey..Misery?? The machine is so happy it will dance!
 

Thread Starter

madsi

Joined Feb 13, 2015
107
I use a different approach. I bought a clothes washer about a year ago. After examining every part of it, I ripped out the wiring harness and installed my own design. There is nothing left of the original controls except the motor drive and the fill switch. :)

Here is one of several pages of my modifications:
The page of modification you share here will only get you in hot water (ok maybe cold water too).
 
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