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I'm curious as to what the differences are between those vintage motors which are specified by the manufacturers as "2wd motors" and those which are specified as "4wd motors". I'm in the process of looking for various vintage brushed motors for both 2wd and 4wd cars and it seems to me that the wind/turns of a motor are/should be the determining factors as to whether a motor is suitable for 2wd or 4wd.

Is there a specific rationale behind why the manufacturers label one motor as 2wd and another as 4wd? Can anyone shed any light on this?

Brushed motor performance was driven by winds/turns, but also the armature blank. Even thou the motor was a 12 turn double, it may have been wound on a RPM or Torque armature blank. So the higher RPM lower Torque motors would be run in 2wd and the opposite for truck or 4wd.

MIKE VALENTINE wrote:Brushed motor performance was driven by winds/turns, but also the armature blank. Even thou the motor was a 12 turn double, it may have been wound on a RPM or Torque armature blank. So the higher RPM lower Torque motors would be run in 2wd and the opposite for truck or 4wd.

Thanks for that explanation. Can you just clarify what you mean by "armature blank"? I've never heard that term before. Thanks.

CNA75 wrote:

MIKE VALENTINE wrote:
Thanks for that explanation. Can you just clarify what you mean by "armature blank"? I've never heard that term before. Thanks.

that's the (3) bit(s) of iron around the axle that the wire is wound around... different sizes and shapes will create different magnetic fields and dynamics.

For most of us mere mortals running a good mill is mostly about keeping it in good condition though (comm and bearing in good shape, right brushes, proper gearing ...) which matters waaaaaaay more than armature blanks

Paul

An amature blank is made up of alot of 'bits' - lots of small plates in a tri-shape (called a pole) that are stacked together (I think this is do with eddy currents which improve the magnetic force and therefore power) with the axle running down the middle. The windings are then wound round each of the three 'poles' and join to the commutator.

I seem to recall that stock motors had the biggest variance in blank shape, especially from Trinity. I think the term 2wd/4wd motor was more about saying 'this wind would suit a 2wd' and therefore have less torque as only 2 wheels are driven. A 4wd can obviously handle a motor with more power/torque, but realistically you could run either in both classes...

Just my 2p....

I agree with Paul though, keeping the comm skimmed and the brushes in good condition (if they look burnt, replace them!) and check/oil the bearings regularly...I dont miss that at all with brushless motors - just the odd oil drop from time to time, no faffing with comm lathes etc...