Goldenmotor HPM5000B stator revision differences

[boostjuice]

So as far as I can tell, Goldenmotor have at some point in time revised the stator design for their HPM5000B Axial Flux motor (and possibly also for the HPM10000B).

ES member 'Gestalt' posted internal photos of this motor's stator/rotor in November 2009 showing 8 magnets and 24 teeth.

Opening up my motor which has a build date of I think around early 2012 it can be seen that my version has the same 8 magnets but....... 12 teeth.

Can anyone shed some thoughts on:

A: Why Goldenmotor changed the design?
My potential list of suspicions include; reduced end turn losses, less winding labour/cost, increased optimisation of copper/iron ratio, lower required PWM current limiting frequency required to control the motor at full mechanical speed (6000rpm) using their proprietry range of controllers?

B: What relative effect this might have on the motor's behaviour considering that copper fill may or may not be the same (ie. rule of thumb effect on max torque vs continuous torque)

C: Which version of the motor might actually reflect the dyno chart/ dyno plot on Goldenmotor's website?

24 slot

12 slot

 

[neptronix]

Ah, keep in mind that there are 3 different windings of this motor.
The 72v motor seems quite different in terms of performance it puts out, and no-load RPM ( quite a bit higher ), compared to the 48V and 96V windings. You'll notice that it has higher efficiency as well.

Can't say that i understand the difference between the two motors though. Usually a pole count means a magnet count increase. Usually more poles means for better torque lower in the RPM band..

Let me guess, this is the 72v motor pictured here?

 

[boostjuice]

Gestalt's pictured 24 slot stator is wound for '48V'
My pictured 12 slot stator is wound for '72V'

However, I don't inherently see why the designer should need to alter tooth counts to get near enough to the Kv they want for different system voltages.

 

[neptronix]

You wouldn't need to change the tooth counts, but halving the tooth count for the higher RPM motor could explain why it can get higher efficiency ( from lower eddy losses, if that applies here? and maybe less end turn losses too? ) at the higher RPMs.

Just be happy that you coincidentally picked the most powerful one :lol: