QS 273 motor damaged by water?

[Adrian_]

I have a QS 273 V3 5T motor with about 800 miles on it. Yesterday I was doing a full throttle pull from stand still when at about 20 mph the throttle cut out and the whole bike started vibrating, it felt like phase wires were shorted. I pulled over and then got a "Hall sensor" error on my display. I opened the bike up and unplugged the hall plug and inspected it, it look fine so I plugged it back in and I was still getting hall sensor error so I plugged it into the motors backup hall set as the QS motor comes with two sets of halls and the hall error went away and the bike worked fine.

After about 8 miles, the throttle cut out again and got hall sensor error. This time the main set nor the backup set was working, kept getting hall error on both so ended up walking home. What I did notice was that depending at what motor position I turned the controller on, it would either instantly give me a hall error or it would allow the bike to nudge forward a bit before cutting out throttle and giving a hall error. If I turned on the controller and didn't get the hall error, if I manually rotated the motor slightly, it would give me a hall error so to me it looked like possibly a wiring problem as I doubt two sets of hall sensors would fail after 800 miles and withing 8 miles apart from each other.

Today after the bike was sitting overnight, I turned it back on and it worked fine for about 20 feet before it cut out and gave me hall error again so I knew the problem is either inside the motor or with the wiring between the controller and the motor. I didn't bother testing the hall sensors with voltage meter, I went straight to taking the motor apart so I can continuity test all the hall wiring as a wiring problem seemed more plausaible to me than faulty hall sensors.

When I opened the motor, a decent amount of water came out and found multiple spots of corrosion on windings and even a broken winding which seems to have been caused by corrosion. After seeing that, I came to the conclusion that this was most likely the cause of my issues and the halls were fine. I took some picture.

I highlighted the corrosion and the broken winding. The other side looked in very good condidition compared to this side, only one little spot of corrision. I'm not sure if this broken winding is the cause of the hall errors. Could I even save this motor? I was thinking about letting it dry, then clean up the corrosion with a soft brush and alchohol, solder the broken winding together and use spray on insulation, seal the motor with high temp silicon and never use it in the rain again.

 

[DogDipstick]

I dont think it is the water that is the problem.

I have run a hub motor soaking wet for a couple years... Opened it and two cups of water came out. Rusty rusty form time. However, there was ZERO green corrosion on my magnet wire windings...

I have never seen green stuff in a hub like that.

It is that tiny break in the winding...... that tiny, one, little short. Cause of the problem. A hubby will NOT run if its windings are shorted.

Test the halls. If they work.. then check the winding for shorts ( correctly, NOT with a multimeter, but with a motor winding checking tool). One of those tests will fail. There is the problem.

That break in the winding is the short. Needs rewind. Motor is done.

 

[DogDipstick]

Did ya get chlorine on it somehow? ( Chlorine oxide).

 

[Adrian_]

[/quote]

I dont think it is the water that is the problem.

I have run a hub motor soaking wet for a couple years... Opened it and two cups of water came out. Rusty rusty form time. However, there was ZERO green corrosion on my magnet wire windings...

I have never seen green stuff in a hub like that.

It is that tiny break in the winding...... that tiny, one, little short. Cause of the problem. A hubby will NOT run if its windings are shorted.

Test the halls. If they work.. then check the winding for shorts ( correctly, NOT with a multimeter, but with a motor winding checking tool). One of those tests will fail. There is the problem.

That break in the winding is the short. Needs rewind. Motor is done.

I agree with you, I have a hub motor that is 2 years old with 12k miles that looked better than this one. After doing some research, people fix broken windings in transformers by soldering the two ends together, I'll attempt the same, not like I can do any more damage. I'll sand down both ends to get rid of the varnish, then solder them side by side this way I don't rely on the solder to be the point of contact incase it cracks from vibration or heat cycles and then cover the solder joint with JB weld to give it strenght and see if it works and if it does, how long.

Did ya get chlorine on it somehow? ( Chlorine oxide).

Nope, the motor is 4 weeks old with 800 miles and this is the first time I opened it. There was about inch of water 2 weeks ago which is how I think water got into the motor, there was about half a cup when I opened it. Whatever contaminants were in the flood water must've made it inside which is what started corroding the varnish on the windings. I also noticed that the corrosion is only on the first outer 2 or 3 layers of windings where they would be in contact with the water inside when the bike was standing still, there's no corrosion on the inner windings. The spot where the broken winding is is the worst spot, I also verified with multi meter that the corrosion made it completely through the varnish so I will have to re-seal it to prevent it arcing and shorting. The other spots are fine but I will re-seal them just incase anyway. I'll also wash all the windings with isopropyl alcohol to get rid of any contatiments still left on the windgings. The motor was left to dry for the past 2 days and seems to be fully dry now.

 

[amberwolf]

When you do the repair, I recommend something like CoronaDope (some links over here
https://endless-sphere.com/forums/viewtopic.php?f=28&t=117672&p=1736182&hilit=coronadope#p1736182) with some other info that may be useful) as an insulator you can soak the windings in after you've neutralized whatever is corroding them and removed all the corrosion, to prevent any inter-winding shorts.

If y'all get your roads salted for ice/etc, then if the motor was filled with water runoff from a flooded road, it could corrode things whose insulation was already damaged (nicked, etc) during manufacturer of the motor. Normally that would also heavily corrode the steel and other iron-based parts of the motor, and even the aluminum, but it doesn't appear to have done so as badly as I would expect. I haven't seen this corrode the actual winding insulation however; that enamel is usually pretty corrosion resistant, so it's more likely that was enabled by physical damage to the enamel in the winding process.

 

[mxlemming]

Looks to me like a rock or bits of swarf or something were going around inside the motor chewing up the sides of the windings. That enamel is usually some kind of remarkably tough polymer... And almost completely impervious to water... Until you turn on the driver, at which point 70V or so says corrosion accelerates at any little crack or exposure of the copper.