front loaders with transmission...
Hi Louis.
Siemens definitely made a motor for front loaders that had a "transmission". Would have been 1970s or early 1980s? I have the remains of one in my shed, not complete. They use a two-speed induction motor, drive through a 10-to-1 reduction gear, to a large diameter cast iron pulley. The pulley is hollow and has a centrifugal clutch inside it. Here is how it works:
Slow speed -Slow winding is energised, motor turns at slow speed, something like 1440 rpm. The motor drives through a 10-to-1 reduction gearbox, turning the cast iron pulley at about 140 rpm. The belt drive to the drum is approximately 3-to-1 pulley ratio, so the drum turns a bit under 50rpm. => WASH. Motor reverses, so tumbling reverses.
fast speed - Fast winding is energised, motor turns at fast speed, something like 2880 rpm. Drive continues through the gearbox and pulley, initially driving the pulley at 280 rpm so drum turns at a bit under 100 rpm, a short burst of a distribute speed. But at the higher speed the centrifugal weights move outward, pressing the clutch surfaces against the inner face of the hollow cast iron pulley.
The clutch bypasses the reduction gear, so the cast iron pulley starts to turn at motor speed - 2880 rpm. This gives a drum speed of around 1000 rpm. => SPIN.
It is a very elegant solution to giving a faster spin speed than you could get with the 2 speed induction motors used in cheap Italian machines of the time, without the noise and unreliability of the brush motors of the 1980s. It would have been expensive to make, though.
I have one salvaged from an early Asko or Asea front loader with the drop down outer door. I used to work nights and more than 20 years ago I was driving home from work one night when I saw an unfamiliar machine dumped at the roadside for a hard rubbish collection. It was a Constructa, built like a tank and it had the same motor. I had no hope of lifting it into my car and I tried to salvage the motor, but I didn't want to wake anybody at 2am so when the bolts were too tight to remove easily I reluctantly left it there. Constructas were never sold here so it must have arrived with someone moving to this country.
My Asko 12004 had another Siemens motor, again 2 speed without any electronic controls, induction motor for slow speed and brush motor for high speed, and I have never really understood how they work as they are NOT two motors in line on one shaft like Miele used, they are two different technologies working in one motor. I have a couple of salvaged ones and should pull one apart one day just to try to understand it...
Final mention is for the good old slant front Hoover Keymatic. They used a reduction gear on the motor, giving a fast pulley for spin and a slow pulley for wash. Each pulley drove a separate belt to a separate pulley on the back of the drum, and each pulley had a one-way clutch so driving clockwise drives the drum and the pulley turning anti-clockwise doesn't drive, it just idles. To change from wash to spin, the motor reverses, meaning the slow pulley now idles and the fast pulley now drives.