motor gradually quit getting power

[Kevin]

I was riding my 750 watt hub motor system to work today and over about twenty minutes the motor failed. The motor kind of cut in and out for a while, then cut off altogether. I had to pedal half way to work. I checked the various connections and found no obvious connection problems. I didn't have a voltmeter with me, so I couldn't see if the motor was getting electricity. The CycleAnalyst was functioning fine and registered a voltage output of about 38V from my 36V 20 amp battery.

The bike/system has about 300 miles on it.

What do you think might have happened? Is that how controllers go out?

 

[Demosthenes]

That sounds more like a controller or battery hitting LVC (Low Voltage Cutout) which would be because of the battery. But then your Cycle Analyst would cut out also. Controllers typically fail catastrophically. If it's intermittent failure it's generally either a protection cutout or 9 times out of 10 a loose connection. Unfourtanetly they are never easy to find!I've had similar things happen and it turned out to be the fuseholder (The fuse was fine, but the holder had arced and melted and corroded into a mess) Then it was a connection within the battery istelf. So step 1 would be check every connection (And sometimes you can even get breaks in the wire) very thouroughly! Start with the ones carrying power. After that check your throttle and brake line (And check the lever itself, if the switch is staying on, that can definitely do it) It's likely not to be the phase wires (I'm assuming a pretty typical brushless motor) because the motor wouldn't cutout entirely it would kind of grind. Nor is it likely to be the hall sensor but check these things also!

 

[dogman dan]

Sounds pretty similar to one of two things, either a hall sensor slowly burning out, or a bad connection on a phase wire. I've have two cases now where a phase wire rubbed a tire unknoticed cutting or shorting it, so look at that , and where the wires exit the hub, and look for connectors pushed back in the housings on plugs. If barely connected at the phase wires, it will run with very very low power, and the cut off when the connection completely breaks.

 

[Kevin]

Thanks to both of you for your thoughtful responses.

1. Where will I find the hall sensor?


Again, thanks.

 

[dogman dan]

The hall sensors are buried in epoxy inside the motor. Replacing them can be done, but they are very tiny, and it takes a bit of mechanical and soldering skill.

The tech reference section should have a thread explaining how to test a hall sensor, or maybe I saw it on the Ebikes ca website troubleshooting page.

 

[Kevin]

1. The cycleanalyst is getting power.
2. The throttle lever off the contoller is getting power.
3. The controller is not delivering power to the motor.

Someone is going to have to open that controller. Think I'll contact hightekbikes.

 

[dnmun]

i thought the aotema was sensorless so you should not have hall sensors in the hub. i think someone had isolated this problem to a surface mount resistor which would burn out that was part of the sensorless controller's zero crossing detector which takes it's signal off the phase leads. terry should know.

 

[amberwolf]

Do you have ebrake handles? Any wet weather? If so, it's possible the sensor or wire for that got damp and is at least temporarily shorting the signal line to either power or ground, causing the ebrake to trigger. That would still allow the controller to be on, providing voltage to everything except the motor.

Or a wire inside the ebrake line could have been worn or cut as dogman describes, or from vibration against the frame, and shorted inside the cable. THat would do the same thing.

Easy test for this is disconnect the ebrake plugs off the controller end, and retest. If it works try one handle at a time, probably only one has a problem.

 

[dogman dan]

I didn't notice aotema in the sig. It could be just a bad connector, the bullet type used on the aotema can fail easy somethimes. Or there could be a nick in the wires at the hub, which could blow the controller. We've seen a few cases of that, a tiny nick at the hub blowing several controllers by shorting the phase wires. So look very hard at that before trying a new controller.

 

[Kevin]

I don't have e-brake handles. I didn't see any nicks at the hub. It hasn't been wet.

 

[Kevin]

I corresponded with the good people at HIGHTEKBIKES.COM, who told me that the controller is under warranty and will be replaced for free.

Gotta be happy about that!

I'll be back up and riding soon!

 

[dogman dan]

Good place to spend your money, at High Tech Bikes. Still trying to kill the Aotema he sent me for destruction testing, can't do it at 36v or 48.