Inside heat abused WE BD36

Hooray! motor is all fixed, and runs normal. No loss of power, or rubbing noises so far. We'll see what PC-11 can handle when I heat the motor up good next week. But for now it runs fine. Now I know that the brushes are fine. There is some signifigant discoloring in the windings though, so if it slows down it's because I melted some varnish or whatever it is that paints the winding wires. But so far, it still goes 25mph on flat ground, though it does take a half mile or so to develop the last few mph.

After an 18 mile ride this morning, the motor is working fine. One more detail. The telltale symptom of the loose magnets was a loud snick sound from the motor when the power was turned on and off at the throttle. This must have been the sound of the magnets moving around when the windings energized. So if your motor does this, now you know why.

I would say, the difference would be, don't climb up a hill for 15 miles every day in over 100F heat. The brushes didn't fry, the epoxy on the magnets did. That would be the same glue in either motor, if you roast it like I did. At the time, I couldn't lift the bike onto a bus bikerack since I was still recovering from double broken collarbones. now that I'm better, I'll take the bus if it is over 95 degrees. It was a pretty easy fix though.

People say that drilling some vent holes really helps. This hub motor is the only electric motor I've ever seen without a fan to cool it. Now that it's our rainy season, I'll pass on that, but maybe next summer.

I still like my brushed motor, since it's fast on 36v, and climbs hills, er... too good.

Yeah, I figured some kind of screen attached inside, and then I could tape the holes shut if it rained. But now it's raining a bunch, like 8 1/2 inches in my guage in the last 3 weeks, in a place where 9 is the annual average. So it's not 105 anymore for sure, and with humidity, air will cool the motor fine. When I cooked the motor, it was 105 and 5% humidity. Back when I had WV bugs we used to have to spray down motors every 50 miles in June, our lowest humidity month. In june, air holes might not work anyway in the 5% humidity. Letting a bus carry the bike up the hill may be the best plan in the end. The bus has nice AC, worth the 50 cents. I just couldn't lift that bike onto the rack till the bones healed up more.

The motors do get pretty hot normaly. If you have the BD, that is pretty much normal range for full throttle riding. I think the BL is supposed to go 2 or 3 more than that at full throttle all the way. My other motor was doing the same route when it was 95 F and it is fine. I only damaged the other when it was 105 F. Still, it is worth thinking about cooling better if you get a Lifepo4 that lets you ride non stop for an hour or more. The designers were pretty sure the batts would only give you 30-45 min at full throttle. I was using a squirt bottle on the hub on the part between the spokes to cool it off a bit after the noises started.

I don't know, but I suspect going 5mph faster is hotter. Since you run more watts through the motor in a shorter time, it gets hotter. I'm guessing on this, but it makes sense to me. Mechanical resistance is what heats the motor. It runs cool with no load, and a little hotter the more weight, wind, or hill it has to overcome.

Did the full commute today since I missed the bus. The repaired motor zoomed up the hill from hell in 96F with no problems. Since I keep getting stronger, I set a new speed record. Topped the hill at 18 mph. Not bad for a mile of 10%. Now that we have humidity, the motor is not slowing down anymore from heat.

More fun with the heat abused motor. Today I went out trail riding for the first time, so I'm going up rocky little paths in the desert at the base of a local small mountain. Pretty soon the motor gets nice and hot, going uphill at less than 5 mph. Suddenly the wheel stops, but the motor keeps spinning. Like somehow, you can hear it turning in there, but it's not moving. I think, wow, the hub is hot, but the axle isn't and now it must be spinning. When I get home and crack er open, nothing to see inside. Huh??? Now that I look at it, how could it do that without twisting up the wires anyway? What the Heck????

Looking closer, I see the part the magnets are stuck to is a two piece assembly. sort of like a wagon wheel had the steel outer part and the wood inner part, but in this case both pieces are steel. Heating the outer band of steel makes it big, and then when it shrinks in place it grabs tight. When hot, the band is now too big and can slip, so the magnets go round and round while the wires and axle stay stationary.

Because of clearance issues, the only fix I could think of was to take a chisel and an anvil and punch a bunch of notches in the edge of hub and magnet holding band, hopefully deforming it enough to grab. And knocking most of the magnets off in the process. Fun with magnets again. Never let more than two clump together. 5 stuck together was nearly impossible to separate again! The more that stick together the harder they hold. Could barely get it off the washing machine top let alone get em apart again.

We'll see if this motor runs again, but if not, at least I learned a lot about how they are made.

Send me any free stuff you want tortured. I'm notoriously hard on tools, trucks, dirtbikes, and my body. Still, I consider this normal use, that things should be able to take or they are junk. I'm not talking about running engines without oil, just using it normaly all day sort of thing.

But woe, the motor now runs slow as a turtle, about 10 mph slower. I must have mixed up magnet polarity or something I am ignorant of. Or I melted the winding insualation. Oh well, I figured I had little time left on the thing anyway. I'll put it on the trike now, since slow is good on the trike. Next motor, I think I better try geared.

Thanks to helpfull Snowcrow on the ES, I figured out the magnet arrangement and have the motor fixed. Passing another magnet over the magnets on the hub reveals the orientation. Basicly the magnets are in pairs, and a magnet passing over the pair will be attracted at the opposite sides of the pair, and in the middle between the pair, repelled. So If you are ever re sticking magnets and get mixed up, that is how they should be. My big mistake was removing more than one from the hub at a time.

The heat abused motor, alas, is now dead again. It might just be brushes this time, but I am going to give up at this point, and get another hub. Each fix seems to go only a few miles, so I think maybe its time to just give up on the axle and magnet part of this motor. Snowcrow tells me I may have overheated and damaged the magnets themselves. In any case, it still runs too hot all the time now.