Hi Steve, hope all is ok for you over there?
Yes I think there is no doubt that the motor is constructed as a 3 phase external rotor motor - but therein lies the rub.
- capstan terminals.jpg (77.41 KiB) Viewed 11280 times
These motors, apparently, can provide the 2 tape speeds 3-3/4 and 7-1/2 by "pole changing" - i.e. changing the wiring configuration similar to this:
- bapst wiring.jpg (35.82 KiB) Viewed 11280 times
In addition I am assured by the donor of this motor that it is run from a single phase supply (with the cap providing the phase difference).
Whilst I know this can be done with a two phase motor I am not aware of how that works with a three phase motor - the best I can come up with is a "fake" 3-phase supply whereby on coil is supplied by the active, another coil is supplied with the same active but reversed (i.e. 180 degree phase shift
) - the donor says via the neutral but that is what he must mean by that - and the third is supplied by the active through the cap - apparently this CAN work (although I remain sceptical) but the motor runs poorly and gets hot - maybe for low torque applications this is OK - this is all news to me so I am groping for more info.
In particular I would like to know (if there is anyone who is familiar with this motor):
Things I can't figure out:
What do the letters to the left of wye/delta symbols refer to?
Why is there a dash under the uF column heading for the first 2 options and what are the numbers immediately to the right of those?
Why is the rated wattage different for the third option? (I am assuming that the cap is performing some p.f. correction perhaps?)
BTW apparently these things CAN be run off 60 Hz and the correct speed is then obtained by changing the pulley diameter.
Anyway just a little more info (and a lot of pure uneducated guesswork on my part) that may strike a chord in someone's memory.