In older clothes-washing machines with no electronic controls, how is the high speed for the spin- dry cycle achieved? Is it by pole-changing?

 

Perhaps it depends on the manufacturer. I suppose most just switch full current to the motor. Is this homework?

 

In the older machines that I have investigated, the higher spin speed is provided by a mechanical shift mechanism. A very few machines used a dual speed motor, but never a pole-changing scheme.
In the Westinghouse twins case, there was a separate 10:1 reduction transmission enabled for the wash cycle and bypassed for the spin cycle.
In the dual function, washer/dryer machines that was often an actual gear-shift in a gearbox.

 

Older maytags didn't have a shift mechanism, instead they ran the motor one direction for agitate and the other direction for spin.
The transmission had gears to generate the back and forth motion for agitate. When the motor reversed an internal nut
ran down a threaded part and locked up the transmission so the whole transmission & washer drum rotates. So the only
capability the controller (clock motor & lots of switches) needed was to start the motor either forward or reverse.

Look up Maytag model A610...

https://www.partselect.ca/Models/A610/

 

I never had to fix a MAYTAG for anybody. It seems that they lasted and lasted, And lasted.
The scheme of reversing the motor was used by one of the cheaper brands to reverse the pump flow to drain the water, or to circulate it. Reversing an induction motor is easy and simple and cheap.

 

Older machines typically used a gear box on the motor shaft, the new versions now use the new Fisher-Paykel outrunner motor, i.e. NO gear box at all
https://www.fisherpaykeltechnologies.com/knowledge-hub/direct-drive-washing-machines

 

Older Maytags were built to last. I inherited my grandmother's mid-70's vintage Maytag in 1991 and used it until the transmission started leaking oil into the laundry in the early oughts. I replaced it with another Maytag but that one didn't last long at all. It looked almost the same as the older one but the sheet metal on it was half the thickness of the older one. You could tell the bean counters had gotten to it and cheapened it up.

I recall my Mom's Kenmore using solenoids to shift the transmission. I was impressed that the Maytag didn't use them, fewer failure points.

 

Older machines typically used a gear box on the motor shaft, the new versions now use the new Fisher-Paykel outrunner motor, i.e. NO gear box at all
https://www.fisherpaykeltechnologies.com/knowledge-hub/direct-drive-washing-machines

I have seen several of those new front load machines out at the curb for disposal, I suspect that when the repair guy can not discover the source of the problem, he decides it must be the processor module, and the charge to replace that is half the cost of a new washer machine.
When I was asked to provide a second opinion on one of those calls, I looked at the service guide, keyed in a reset command, pulled the plug out for two minutes, plugged it back in, and the machine was repaired. My tip for that fix was more than my invoice. And the client was very happy as well. AND my reputation was enhanced among that group of folks.