Neumotor 8057/75 middrive project, belt drive, adding halls, 10kW+

[fechter]

If the hall sensor is located exactly at the middle of the magnet you could have no flux in the direction of the sensor axis (fail). If the sensor axis is off a little from the middle of the magnet, it should work fine.

If you powered a sensor and watched the output while trying different positions you could verify a good signal.

[coleasterling]

It is tested and switching well. The slots are slightly longer than the sensors to allow moving them across the thickness, but I didn't end up needing it. Controller testing will happen tomorrow or Tuesday and we'll see for sure. I'll probably throw the scope on it, too.

[coleasterling]

I realized it was somewhat difficult to tune the hall position due to some dumb dimensioning. I reworked the part today for more adjustment range (On gap? Middle of tooth? Somewhere in-between?) and better centering. Don't quite get the relationship between initial hall position and termination yet, other than being 30 degrees different.

Anyway, I made the ID of the ring smaller than the motor mount's hole (instead of larger) and turned a tight-tolerance insert that allows me to tune the hall position without worrying about concentricity until the mounting screws are tightened.The screw in the end of the insert lets me pop it off when tuning is done. I didn't get it fully wired up today since I made the design revisions, but will have it running tomorrow.

[coleasterling]

Made yet another revision, this time to allow building of the hall-sensor module off of the motor, and for much better wire routing.

This is after tumbling it to deburr in our 4-foot diameter vibratory tumbler with polyester tetrahedrons.

Edit: I can't change the orientation of the image for some reason.

[nowholeself]

Made yet another revision, this time to allow building of the hall-sensor module off of the motor, and for much better wire routing.

This is after tumbling it to deburr in our 4-foot diameter vibratory tumbler with polyester tetrahedrons.

Edit: I can't change the orientation of the image for some reason.

I want one!

[nowholeself]

My Neumotors 8025 has just arrived. It is so small! My original plan was to attempt to at least match, if not beat, the power of an ASI BAC800 controlled BBSHD. But can something so tiny really do that!?!? Maybe I should have gone with the 8038...

[fechter]

If you apply a steady current to a pair of phase wires, the rotor will align to a certain spot and this will be exactly where one of the halls should be right at the switching point. By jiggling the rotor a little, you should be able to dial in the position so the hall signal toggles, indicating the timing is neutral. This would be a good starting point for the timing.

[coleasterling]

Ah, makes sense. Manual version of setting a digital encoder or resolver.

This solution works quite well...when the halls are functioning. Twice now, I've had the bike running well, then come back and the halls were all shot. Not sure why. They definitely aren't touching anything and there's no physical damage to the halls, mount, or hall harness. It wasn't getting hot enough to kill them, either. Color me confused.

Anyway, nowholeself, if you did want one, I'm happy to send the last one I took photos of to you. I realized there wasn't enough clearance to the stator windings with it, so it couldn't move as much as I wanted. I think the easy solution if you did want it is to just bend the legs slightly out. I haven't been able to tell any difference in function with a bit of angle on the halls. I can't really envision the 3d flux path that makes it work in the first place.

[madin88]

Twice now, I've had the bike running well, then come back and the halls were all shot.

Thats weird. hope you find out what the problem is.

It wasn't getting hot enough to kill them, either.

The holder is made of aluminum so there will be eddy currents, but i hardly think that this small surface area behind the halls would heat up so much to toast them.

[coleasterling]

The holder is made of aluminum so there will be eddy currents, but i hardly think that this small surface area behind the halls would heat up so much to toast them.

Thanks, they definitely weren't significantly heating. I really don't know. Now, I'm not running resistors, but I never have on ss411a's and they've been just fine, even with this exact controller. Strange deal. I'm out of halls now, but might buy more and wire the resistors just to check.