SMC - Soft Metal Composite (future stator design)

Hi

I have been researching the possibility for a composite stator for BLDC designing. It seems that the possibility exist. Here is some interesting reading: https://www.sintex.com/en/about-sintex/cases/item/stator-design-med-smc

Unfortunately these composites need very high pressure and special tooling.

The upside to SMC is apparently better field strength compared to laminated stators, but with the tradeoff of higher stator loses. Due to the manufacturing process, the stator can be designed to hold more turns of copper wire, compared to laminated stators, which makes it possible to design more compact motors.

These composites have a 200 celsius specification, so they must use a industrial high temp epoxy.

I think it is a danish company, so I will try to reach out and ask about the cost.

It would be soooo cool to se such a stator in combination with a halbach array.

Here is a interesting compunt; iron flakes.

The main challenge in doing a composite stator is the FE (iron) powder being seperated by the epoxy. By introducing FE flakes, perhaps in layers, this will make a magnetic layer or layers. Maybe it is sufficient to make a porridge with the right formula (high temp epoxy, iron powder and iron flakes).

Or, thin film iron (0.05mm).

Layering this with the epoxyFE porridge, you can achieve the same amount of layers as a stamped out laminated stator, reducing eddy current´s. Doing this, the overall non chipping performance will also increase.

The advantage of making this kind of stator, is the ability to design a stator with the ability to hold more turns of cobber wire, not bulking out. In practice, this means you can make a 24v BLDC with the same torque as a 36v BLDC with the same dimensions (width). So the increase in cobber effectiveness translates to a lower voltage motor and therefore longer range because of more amp hour´s on the 24v battery compared to a 36v battery and so on. Naturally, driving the motor with higher volt´s increases the performance. The dimensional advantage can be translated to a hub wheel BLDC running on 24v with the same performance as a higher voltage one, where the traditional bulking out of the windings result in a overall wider motor.

I believe you can cut the thin film iron with a scissor.

Bling bling

https://phys.org/news/2017-03-czech-scientists-magnetic-carbon.html :smiley:

JASEP_Stator_composite_laminate Ø50cm

Do smaller magnets in a halbach array outperform larger magnets that would fit into the same space?

halbachvsalt<

Im no expert


Source https://www.skf.com/binaries/pub12/Images/0901d196809590fe-Slewing-bearings_tcm_12-513670.pdf#cid-513670

Found a very robust bearing. Have no idea about the cost, yet. Overall diameter scaled to 42cm

Standard bearing footprint

2mm stainless steel, can be cut by laser

The main reason for the bearing size selection is the center hole diameter. Here I have downgraded the iglidur slew bearing (58 euro). It should be possible to sandwich two 1mm sheets and perhaps fill the gap with foam. This bearing has a 30mm center hole, which should hold wires and maybe cooling.

Edit: Those slew “slide” bearings can’t go above 200 rev/min. Most likely due to friction.

Halbach segment x 5

1" kevlar

halbach  sektion 2 overlap