I know this posting has gone a bit off topic but I am enjoying the exchange of information.
The use of induction motors in washingmachines is not common here in the UK
I asked the experts at
UK Whitegoods about speed control and this is the answer I got. intresting
New postPosted: Sun Apr 01, 2007 6:26 pm
the formula you quote is for induction motors. carbon brush motors (series field) in theory are load dependant and have no top end speed if run unloaded with a un interupted supply. electronic speed control chops the 50Hz sine wave thus giving a burst of supply every 100th's of a second. by altering the length or this burst of supply more of the sine wave cycle is allowed to be completed and and thus the speed altered. the tacho generates a small voltage fed back to the module as a referance
well something like this!!!!!!!!!!!!!
wilf
