In article ,
Richard Faulkner writes:
In message , Paper2002AD
writes
But then, what do I know, I only worked on washing machine development
at Hoover for eight years!

Aha!!

Just as a matter of interest, I let a few flats and the Hotpoint
machines vibrate like hell on any spin, whereas the Hoover are almost as
smooth as silk.

Funny, my experience was different when I switched from a
Hoover to a Hotpoint. The Hoover used a drum speed when draining
out which was just fast enough to keep the cloths stuck to it
at the top of the drum, so as the water level dropped, the cloths
were evenly distributed around the drum, mostly. However, it had
no check for this, and on occasions where it went wrong (like if
everything else in the wash somehow got itself inside the pillowcase
you put in), the Hoover would still go on to spin at top speed and
dance across the kitchen floor.

The Hotpoint doesn't use this critical drum speed whilst draining,
but instead, once drained out, slowly increases the drum speed
with the intention of again getting the cloths evenly distributed
by the stage it has got fast enough that the cloths are sticking
to the drum without tumbling, and then switches to the spin speed.
In my mind, this doesn't work quite as well as the Hoover method
of doing this whilst draining the water, but the Hotpoint does use
a means to measure the unbalance of the load in the drum. If it's too
bad, the Hotpoint gives up, stops the drum and rotates it backwards
a bit to break up the ball of cloths, and then tries again. It has
up to 3 goes at getting the cloths evenly distributed, before going
on to spin. If all 3 attempts fail, then it still goes on to spin,
but will not take the spin up to the top spin speed (1400 RPM in
mine -- I think it was slightly faster in later models).

Another machine I have experiance with is a Zanussi. This is much
worse than either the Hotpoint or the Hoover. This drains out with
the drum stationary, leaving the cloths in a clump at the bottom.
Then it just starts spinning, with the load pretty much guaranteed
not to be distributed around the drum.

None of these are new machines, and manufacturers may well have
changed how their program cycles work. I would suspect some of the
techniques may be (or may have been) protected by patents.

--
Andrew Gabriel