Hi Nigel,
Yes it is indeed brushless. It seems that transistors take the job that brushes
would do.
Motors ive seen before have mostly been sort of cylindrical, and have coils forming
a cylindrical space where the rotor fits in and spins.
This motor is not like that, the coils are on a plane, they form a flat surface.
The rotor is flat too, its a couple of cm. thick and circular, about 3.5" dia.
It has eight poles, i counted them.
Thing is, its direct drive, so for 33.3 RPM the drive a coil-pair would change
direction sixteen times for each revolution.
It would be pulling for a bit, then the pole would pass, and i guess it would
push for a bit, then i spose it would do the same for the next pole.
There are two coil-pairs, so i expect the other one to be doing the same as
the first. But half a pole out of step, so as to make it smooth.
Thats why i think its a "very low frequency" oscillator, a VLF.
But its not something i'm familiar with, so maybe its just switched DC,
like an ordinary motor, but with transistors instead of a commutator.
My little scope is playing up, soon as i get it running right i'll see if
its a VLF unit or not. If it is then its pretty slow, i reckon about four
cycles per second, roughly.
Its possible that the whole motor drive section is Ok, it doesnt drive til
the pick-up is over the turntable, so ive got to check that bit too.
Regards, John