Disaster

[giguana]

recently I had some problems with a bit of moisture in the motor, so I dried the motor out, sealed everything I could with silicone, and put plenty of Vaseline in the joints of the axles to stop water getting in through the cogs and the wire end. I spent about 15 minutes making sure that I got a little wad in at each end.

I went about 5 m in the garden and started hearing the thudding sound again-so I figured the petroleum jelly must have gotten into the circuitry.

but it gets worse-I look down and the back wheel had fallen out from the bolts because the whole area was in contact with Vaseline, and the cable got twisted about three times over itself.

the wheel was done very tightly but the lubricant made it slip very easily, and now I have the prospect of trying to get the Vaseline out and having to test all the wires. damn.

 

[giguana]

as far as I can tell, despite seeming OK after being dried, it's a lot worse than it was before. Do I have to get the Vaseline out of both ends-can it interfere with the electronics?
so even if you have a nice custom-built bike, if you try and seal it you can run into big problems-petroleum jelly is a bad call near the axle. And that's the only place there is a gap left after you have used silicone. I got the advice from a couple of people but I think it should come with some serious side notes.

 

[flecc]

Sorry to hear of your problems, but I'm very puzzled by this, since vaseline petroleum jelly has very high resistance. It wouldn't interfere in the low resistance low voltage environment of our hub motors, so i don't see a need to get every scrap out.

I've never used it in that way, though I have used it long ago to seal minute gaps in cable entries to junction boxes etc. These days I prefer silicone sealants, though I have used general purpose grease at spindle entry gaps without problems.

The impression I get with that very high torque motor is that it needs an anti-torque arm to positively prevent any rotation.
.

 

[fcurran]

I agree with Flecc, on all electric bikes both front and rear wheel driven, they will almost certainly have an anti rotation bracket which will stop the spindle from spinning the electrics out of the wheel while the bike gathers pace. I fear you may have forgotten to reinstall this piece of metal and as a result you have ripped the cable out. If you have replaced the anti rotation bracket then the vasaline may have acted as a lubricant to help it spin out. Replacing the cable is not that difficult a job however it is time consuming and you must remember the order in which you strip the motor components when replacing them. On your hub motor you will see about7-8 screws. Undo these screws and carefully take each gear and cog out until you see where they join to the centre piece.

This anti rotation bracket can often wear over time especially if the rider is:

a) Powering away from a standing start without assisting the bike
b) Carrying an excess load on you bike
c) Applying the brake while having the throttle open

 

[giguana]

I would prefer if the cable was deteriorated, I have always checked the bolts a lot while I was riding around and they have never gotten undone at all after more than 100 km, and they were still tightly done when the wheel came out. the problem is that petroleum jelly leaves a microscopic film which is a hundred times less gripping than metal against metal...the force of the motor itself is very low.

the cable is still well attached and it didn't look alarmingly twisted, just a little bit, I just don't know which it would be exactly.

 

[giguana]

have found a definite cause for the problem-check the photos...

the assembler didn't laquer all the hall sensors properly, they might have lasted a while in a hot country but in the UK they were bound to corrode very fast indeed- motor lifespan = 100 km...

bare wires very close together on the hall sensors acting like cathode-anode...time to use Jeremy's advice and get some electrical lacquer

fortunately opening up the motor makes you realise how very easy it is to maintain.

I reckon the best way to open it is to undo the screws, lay the wheel flat with some cushions underneath it, gently stand on the spokes as close to the hub as possible and without putting pressure on any individual spokes and it will pop out...that magnets can grip about 50 kg of force to the inside of the wheel so it's quite hard to get out, and the cover plate was very stiff as well.

will be a good opportunity to put silicon/PVC tape onto the groove that holds the plate and the screws in to make it a bit more waterproof.

plus the cable should really be insulated with Kevlar

 

[giguana]

there is actually a hole where the wire used to be. even airborne humidity could have resulted in this. have to get a new hall sensor from ebike.