modern_messiah
100 W
Hello all,
I'd be highly surprised if I get any constructive comments to this seen as this section of the forums seems to deal with modifications of out/in runners more than scratch built motors, particularly AF. No harm in asking though...
I have for the past 6 months or so taken a sudden and strong interest in EVs and given my technical background have become highly interested in the deep down inner workings of their drive train. As such I have decided to design and build my own motor. Having never done anything like this before I decided to start small. For reasons I can’t even remember I am pursuing Axial Flux motors. At this stage I just want to see if I can do it, so no serious thought went into this. I simply picked a rough maximum diameter of the motor and went from there. Hence I have no idea on performance – hell I have no idea what controller to use with it yet!
What I would like is for people who know their stuff to simply say “looks good†or “you have NFI what you’re doingâ€. Maybe even “You can improve it this way…â€.
Some specs:
- 3 Phase, single stator Axial Flux Motor
- 9 Teeth
- 6 Poles (32mmx12mmx3.5mm N48H)
- 36 Windings per tooth (18AWG)
- WYE termination
- Hall sensors placed at 40 physical degrees to each other (360/3 = 120/3 = 40)
- Impeller ring designed to suck air in and over the coils
- The axle is hollow and all wiring will go to and from the stator through this
- 2 RHP 61802 Z Bearings (inner diameter = 15mm, outer diameter = 24mm)
- The axle (steel with a 12mm internal diameter) DOES NOT rotate – the rotors will spin on the previously mentioned bearings.
- The stator is fixed to this non-rotating axle.
- A bicycle gear will be attached to the outside of one rotor, and the motor will be attached to whatever it is sitting on via the axle on the other end. I guess…haven’t thought that through either.
Yes, it’s clearly based on the Launchpoint motor. Please bear in mind that this was designed on a strict “cheap as possible†method. If this works even remotely well I’ll be inclined to design a much more professional version and spend much more money on it. I have no commercial ambitions as this is purely for my own interests.
Below are 4 diagrams of the various parts of the motor. I will be sending these off to be laser cut (rough cost will be AU$140). Some small explanations are also included. Please note the 4 are not to scale as the "stator frame" is significantly smaller than the other parts. Infact the first 3 are drawn on A3 paper, and the stator frame is on A4 paper.
Rotor External. Made from 3mm thick Steel. The centre circle is exactly the same size as the bearing from the centre of rotation to the inside of the bearing’s outer sleave. The 4 small holes on the outside will have a bolt going though each to old the plates and internals together. 2 of these will be made obviously.
Rotor Internal. This is a 3mm thin piece of MDF with shapes cut from it to support the magnets, and the impeller blades. This will be glued to the inside of the External Rotor plates. The bolts will also hold this in place (I am self drilling these). The centre circle is the same size as the outside of the bearing. Again 2 of these will be made.
Impeller Ring. The impeller has 12 small plates stuck sort of perpendicular to it in the half cuts that adorn it’s inside edge. These blades mate with the slits seen on the internal rotor plate and should provide perfect spacing between the 2 rotors the whole way around the motor. Again the impeller ring will have bolts going through these but I will be self drilling them. Only one of the rings and 12 of the blades will be cut. The impeller ring and blades are made from 2mm Aluminium.
Stator Frame. The stator frame holds the 9 coils. It is made from 6mm thick MDF. The coils sit in the 9 large slots and will be glued in place. Holes for the Hall sensors will be self drilled. All wiring will be recessed into the surface of the stator frame (using a Dremel tool or similar) and fed to a hole cut in the axle. The whole lot will be sealed with an epoxy of some sort…I haven’t thought that far ahead.
I’m kind of hoping it will be powerful enough to move a push bike, but if not then I’ll just convert it to a generator instead once my testing is over. Though if the modifications to my design to make it powerful enough for a pushy are simple I may do that as well…
I am still iffy about a few deisgn points, but these are finishing touches (how to hold it all in place on the axle for example - my current "wedge it on tight" method does not satisfy me) and can be worked out easily. I guess this is a "will it work?" from the pure motor perspective.
Good, bad or in between? I must admit I’m very nervous to see what people think. Go easy on me please.
Regards,
- Matt
I'd be highly surprised if I get any constructive comments to this seen as this section of the forums seems to deal with modifications of out/in runners more than scratch built motors, particularly AF. No harm in asking though...
I have for the past 6 months or so taken a sudden and strong interest in EVs and given my technical background have become highly interested in the deep down inner workings of their drive train. As such I have decided to design and build my own motor. Having never done anything like this before I decided to start small. For reasons I can’t even remember I am pursuing Axial Flux motors. At this stage I just want to see if I can do it, so no serious thought went into this. I simply picked a rough maximum diameter of the motor and went from there. Hence I have no idea on performance – hell I have no idea what controller to use with it yet!
What I would like is for people who know their stuff to simply say “looks good†or “you have NFI what you’re doingâ€. Maybe even “You can improve it this way…â€.
Some specs:
- 3 Phase, single stator Axial Flux Motor
- 9 Teeth
- 6 Poles (32mmx12mmx3.5mm N48H)
- 36 Windings per tooth (18AWG)
- WYE termination
- Hall sensors placed at 40 physical degrees to each other (360/3 = 120/3 = 40)
- Impeller ring designed to suck air in and over the coils
- The axle is hollow and all wiring will go to and from the stator through this
- 2 RHP 61802 Z Bearings (inner diameter = 15mm, outer diameter = 24mm)
- The axle (steel with a 12mm internal diameter) DOES NOT rotate – the rotors will spin on the previously mentioned bearings.
- The stator is fixed to this non-rotating axle.
- A bicycle gear will be attached to the outside of one rotor, and the motor will be attached to whatever it is sitting on via the axle on the other end. I guess…haven’t thought that through either.
Yes, it’s clearly based on the Launchpoint motor. Please bear in mind that this was designed on a strict “cheap as possible†method. If this works even remotely well I’ll be inclined to design a much more professional version and spend much more money on it. I have no commercial ambitions as this is purely for my own interests.
Below are 4 diagrams of the various parts of the motor. I will be sending these off to be laser cut (rough cost will be AU$140). Some small explanations are also included. Please note the 4 are not to scale as the "stator frame" is significantly smaller than the other parts. Infact the first 3 are drawn on A3 paper, and the stator frame is on A4 paper.
Rotor External. Made from 3mm thick Steel. The centre circle is exactly the same size as the bearing from the centre of rotation to the inside of the bearing’s outer sleave. The 4 small holes on the outside will have a bolt going though each to old the plates and internals together. 2 of these will be made obviously.
Rotor Internal. This is a 3mm thin piece of MDF with shapes cut from it to support the magnets, and the impeller blades. This will be glued to the inside of the External Rotor plates. The bolts will also hold this in place (I am self drilling these). The centre circle is the same size as the outside of the bearing. Again 2 of these will be made.
Impeller Ring. The impeller has 12 small plates stuck sort of perpendicular to it in the half cuts that adorn it’s inside edge. These blades mate with the slits seen on the internal rotor plate and should provide perfect spacing between the 2 rotors the whole way around the motor. Again the impeller ring will have bolts going through these but I will be self drilling them. Only one of the rings and 12 of the blades will be cut. The impeller ring and blades are made from 2mm Aluminium.
Stator Frame. The stator frame holds the 9 coils. It is made from 6mm thick MDF. The coils sit in the 9 large slots and will be glued in place. Holes for the Hall sensors will be self drilled. All wiring will be recessed into the surface of the stator frame (using a Dremel tool or similar) and fed to a hole cut in the axle. The whole lot will be sealed with an epoxy of some sort…I haven’t thought that far ahead.
I’m kind of hoping it will be powerful enough to move a push bike, but if not then I’ll just convert it to a generator instead once my testing is over. Though if the modifications to my design to make it powerful enough for a pushy are simple I may do that as well…
I am still iffy about a few deisgn points, but these are finishing touches (how to hold it all in place on the axle for example - my current "wedge it on tight" method does not satisfy me) and can be worked out easily. I guess this is a "will it work?" from the pure motor perspective.
Good, bad or in between? I must admit I’m very nervous to see what people think. Go easy on me please.
Regards,
- Matt
