SURRON LB MOTOR DEAD: NEED HELP...

[Jonathan1981]

Motor is off a 2017 Surron LB with ~ 6K km's...

Long story short. One day throttle stopped working so replaced the throttle controller box. No dice. Figured it was a motor issue so opened up the hall sensor cover, seemed like the hall sensor magnet was not lined up with the line on the shaft (Theory is it slipped over time throwing off the timing). I pulled the magnet off, re-aligned it and re-glued it. Everything then worked but upon bench testing it, the timing was a bit off (Motor would spool up but then slow down at full throttle), so I just shifted the hall sensor board (The green slotted plate) a little bit until the throttle seemed to ramp up without issues. Rode it for one big ride and all seemed good. Went to ride it the next day and upon doing a hard pull under acceleration, it jolted, made a loud noise and then obviously stopped working, back to the same issue. The motor cogs heavily now (hard to turn). The theory was the glue I used to reglue the magnet melted or slipped, causing a miss alignment at peak torque therefore making thing go boom... however, upon opening the hall sensor cover again, the magnet and board all appear good, like I left them.

I've called motor shops around and surprisingly, no one seems to work on these motors locally. Just looking for some advice(from those more experienced with EV motors) on how to proceed . Ideally I'd like to be able to repair this vs. buying a new motor... if someone on here knows how to repair these motors, I would even be willing to ship it out for repair (Within US/CAN).
Cheers

 

[amberwolf]

. The motor cogs heavily now (hard to turn).

If it does this even without being connected to the controller, then at least two of the phases are probably shorted together.

You might be lucky and this could be just at the phase wires or connector, anywhere to the point where they interface with the phase windings. That might be easily fixable.

Or the short could be in the phase windings themselves--either overheated, burning off and directly shorted together whereever two phases come across each other, or each one shorted to the stator itself (which could be in completely different spots and not visible).

If the motor isn't potted you may be able to at least find the damage.


If the motor doens't cog when not connected to the controller, then the problem probably lies in the controller itself.


Regarding the board...it has slots for the screws so that timing can be adjusted (usualy called retard/advance). There are marks on those slots that indicate a different position for the board was used at some point. If that position mark was from before the repair, and if the timing was changed sufficiently vs what hte controller had expected / was programmed for, it's possible that the current would've been excessive for either motor or controller or both.

 

[Jonathan1981]

Cogs when not connected to the controller. Something went clunk coming up under hard accel. almost like it wanted to go in reverse or something...

Regarding the board, first/second image is how it came (was working fine for years at that position, until it stopped)... You can see the board is not positioned centered on the slots and the hall sensor magnet (Notch on the brown thing underneath) doesn't line up with the line on the shaft.... in hindsight, they were infact probably set correctly and it was something else..

last image is where I ended up rotating it (To get it to throttle smoothly/properly) after re-aligning the hall sensor magnet on the shaft.

I guess the next step is to open it up and have a look inside.. I'll post up some images...

 

[fechter]

Sounds like a shorted phase winding or phase wire. Probably time for a new motor.

Here's a picture of one apart. I guess you loosen the nuts that seal the phase wires so you can pull the side cover off.

 

[gromike]

I can see some issues with the motor pictured. So, open her up!

 

[Jonathan1981]

Here are some updated images with it all cracked open. From my limited experience, nothing really sticks out to me, no black soot, burn marks, welding or smells. All the magnets looks good. Seems like there was a bit of rubbing on stator segments 1, 2???? Maybe the bearing failed... they seem fine when I roll them, no crunchiness etc. There is the slightest bit of play in the main bearing on the drive side, but it's very very minimal, if I hold the alum motor body plate and try to wiggle the rotor, it will flex a very small amount, maybe less than 1mm..

Ask me questions and I can get further pictures if necessary, I'd like to try to figure this out...

 

[fechter]

It looks clean. Is there any continuity between the phase wires and the iron?

If all else fails,
Surron OEM LBX Motor scratch and dent

 

[gromike]

It looks like you have a bit of rotor rub. As fechter wrote, if the phases and the megohm readings are good, I'd suggest replacing the bearings and run it.

 

[amberwolf]

The only thing that stands out to me is the encoder magnet on the shaft appears cracked. It might or might not disturb the field the sensor detects. If it does, the sensor may not report the right rotor position, and the controller might drive the phases wrong.

That wouldn't directly account for the motor's present issue, but if it overheated the phase wires or windings, it could cause a short that does account for them.

However, I don't see this crack in the older pictures pre-disassembly--the magnet ring on the shaft appears intact there.

 

[Jonathan1981]

The only thing that stands out to me is the encoder magnet on the shaft appears cracked. It might or might not disturb the field the sensor detects. If it does, the sensor may not report the right rotor position, and the controller might drive the phases wrong.

That wouldn't directly account for the motor's present issue, but if it overheated the phase wires or windings, it could cause a short that does account for them.

However, I don't see this crack in the older pictures pre-disassembly--the magnet ring on the shaft appears intact there.

no, magnet was cracked upon taking it apart... hit it with the hammer a few times...

 

[Jonathan1981]

It looks clean. Is there any continuity between the phase wires and the iron?

If all else fails,
Surron OEM LBX Motor scratch and dent

flow through iron/iron is good. Phase wire crimp ends to iron, nothing.

Phase wires, copper to iron, nothing. (Figure the copper might have some residue or protective on it though???
Weird tho, everything looks clean...

Thanks for the link, might have to go that route...