Motor burnout two minutes after completing first build?

[Rylken]

I'm converting a 2009 Giant Boulder using this kit and a Luna Mighty Mini. I just finished the build about 30 minutes ago. I didn't connect the Pedal Assist - just the throttle.

After about 2 minutes of riding, the motor started slowing down so that I couldn't go more than 5-10 km/hour off the throttle. On the SW-900 LCD panel, I started seeing an error code 07, which refers to "motor problems" and sometimes an error code 02, which refers to "brake problems". I rode the bike back home off the electric, put it on a bike stand, and tried to run the motor again. It occasionally ran fast and freely, but then, suddenly, I saw a pale green spark and a burning smell, and the motor stopped running. Now, the LCD panel still lights up, but the motor just gives a soft click when I try to use the throttle.

From reading online, it looks like there may have been a defective Halls sensor. Would you agree that this is the case, and if so, am I somehow at fault for the motor blowing out, or is it just that I was sold a defective unit?

Thanks for your help.

 

[amberwolf]

The most common problem is wrong order of wiring for phases and halls, between motor and controller, causing overheating of motor and controller. Rarely does it work to connect color to color, and even a kit of parts sold together may not be wired that way.

It can appear to work but take excessive power to do so. If this is the cause, then the spark could've been between wires with melted insulation between motor and controller. If that happened, and nothign actually blew up in the controller, then you can go here to figure out the correct wiring order, if your controller has no self-learn feature. (you'd have to check with teh manufacturer for that part).

https://endless-sphere.com/forums/viewtopic.php?f=16&t=3484
https://endless-sphere.com/forums/viewtopic.php?f=1&t=32455


If it's not that, it could be a loose connection, and arcing between the contacts, or a bad crimp from contact to wire. That can also cause melting of connector, wiring, etc., and the RF from the arc can destroy the controller.

 

[Rylken]

Thanks for the quick reply! I don't think there are incorrect connections between motor and controller - I haven't noticed any burned insulation, and I noticed the spark coming from the left (non-drive) side of the motor. Also, I'm not sure if this is correct logic, but I don't think the controller is busted, since the LCD panel still functions fine. I'll take a look at these threads you linked to.

EDIT: Actually, there is burned insulation between one of the three motor and controller connections (the yellow one, if that means anything). I think this was due to arcing between two poorly insulated contacts. Should I be concerned about the motor or controller being busted?

 

[amberwolf]

Also, I'm not sure if this is correct logic, but I don't think the controller is busted, since the LCD panel still functions fine.

THe FETs in the controller (taht provide power to motor) can be completely smoked and the LCD could still work fine--it just wouldnt' spin the motor.

EDIT: Actually, there is burned insulation between one of the three motor and controller connections (the yellow one, if that means anything). I think this was due to arcing between two poorly insulated contacts. Should I be concerned about the motor or controller being busted?

It's possible the controller is damaged from the RF of the sparking, but the motor would be fine from such a problem.

If the insulation is only damaged on one wire, then it is most likley a bad connection between the motor and controller at that point. I'd recommend removing the damaged connectors and directly splicing the wires, then retesting the system.

You can also do the same with the blue and green wires, because it's likely that the connectors for those will exhibit a similar problem later on.

You can replace all the connectors later, if you want to be able to unplug the motor, but I don't normally even use connectors for the phase wires anymore due to this type of problem (I usually splice and solder or crimp them directly together, once I know the system works.

I recommend staggering the splices, so that none of the spliced areas could possibly touch each other. Kinda like bricks in a wall.

 

[d8veh]

Faulty hall sensors normally make your motor make a mechanical noise with a lot of vibration. I'd say the most likely cause was a loose or not fully inserted phase wire connection. As a general rule, ou should never try to conimue running a motor that isn't running properly because you can get severe consequential damage. You should always stop and find the cause, which is often something simple, like a connector issue.

 

[teklektik]

Follow steps in this post to check your motor and FETs:
Testing Controller and Motor with or without DMM

Halls and other tests available on ebikes.ca site: http://www.ebikes.ca/learn/troubleshooting.html

 

[Rylken]

The connector on the yellow phase wire was weak and had broken off on the side connected to the motor, so I had glued the connector back together. The gluing was successful, but this was likely a stupid thing to do, because the glue didn't hold with current passing through the wire.

Luckily, I don't think there was any permanent damage. As a temporary hack, I put the yellow phase connection together with electrical tape, and made the other two connections, and the motor runs fine.

I like the idea of just soldering the connection together and staggering the splices. I have a few more accessories to add on the bike - fenders and racks, so I might do that after those are added on.

Thanks a lot for all your help!