After being unable to find the answer (because I was looking for it the wrong way) via searches, I asked the question at DIY Electric Car forums, and got my answer:
Quoted from that forum, the basic problem I'd face in the conversion would be this:
2 pole armature has the coil sides (wires in the steel slots) spaced approx 180 degrees. A 4 pole armature needs coils side spaces at approx 90 degrees. So a complete wire tear out and rewind is required. And then there are the magnets. You'd need to change to N-S-N-S instead of the N-S 2 pole arrangement.
I'd actually have to remove the magnets, physically cut them in half, etc., in addition to the total rewind of the motor. I'm not sure if I managed to do it I would find enough gain to be worth the effort. :-(
So the quest for easy power continues. :-)
Posts
The post took this time. :)
ReplyDeleteMy excellect Pittman motors have just two magnets and two brushes. The armature has lots of segments, though.
--Joe
Well, if the motors you have are wound with thicker wire, they'll take more current and generally have more torque. The same is true if their magnets are stronger, as there is more field for the armature to push against.
ReplyDeleteSince some of my motors are weaker motors, I had hoped I might be able to convert them to the 4-pole version simply to double the current input to them, by using two armature windings at a time rather than one, for every commutation-segment-rotation, which would perhaps double their torque (and halve their speed).
It's too complex to do, though, for my capabilities and tools.
The armature (well, commutator) generally seem to have 16 segments, at least on the PMDC motors I have opened up for maintenance. For some reason I cannot remember what relation the number of segments has to the motor properties, but my day only started about 15 minutes ago, so I'm a little muzzy. ;-)