I've got a 9C motor open for repair, what else?

Long time, not post here...

I've got a 9C motor from 2010 opened up to replace the hall sensors that went bad, but I am wondering if anyone has any tips or advice on others things that can be done to improve reliability or cooling? I have thought about using a non-detergent motor oil in the motor for cooling, but I don't feel like doing all the work to seal the motor properly to make that work. LMK anything.

Though I love those things, it sounds like you might be overloading a motor like the 9c. Vents on the covers can help a lot, but no cooling strategy can replace running more efficiently, by either riding with less weight, less grade, or pedaling your guts out.

Fix the motor, that's easy. But it might be time for you to seriously look into motors with a wider magnet, and a battery able to run higher amps if your current one wont.

Lurk that for sale used, for a 5300 cylte, or get new HT.

No, it's not being over worked, drawing about 1200watts at top speed (50-55kph) , the motor is warm to the touch after a long ride, but nothing scary... I just thought the extra wouldn't be a bad idea. I am simply trying to do preventative maintenance here.

few things:

1 change the bearings with quality bearings - skf/fag etc....
2 if you live in a wet climate- spray the magnet/metal parts with rust proof coating
3 the 15awg wire should be totally fine in short length- you could put a higher awg wire in- but really if you're not hot rodding - leave it alone
4 some who hot rod, may drill the covers (although this makes the motor 20c cooler- im still concerned about debree getting it) or oil cooling but that is too much effort - if you run it at stock

A temp sensor and thicker phase wires are the most common upgrade. Even if you don't hook up the temp sensor to a read-out right now, it's only $2 and it will be there if you ever do want to get a reading on stator temps (in the future).

ATF (Automatic Transmission Fluid) is the most often used liquid coolant, but if you are certain that you will never want to use oil cooling, simply drilling holes in the sideplates (ventilating) is becoming more common. You can do a preventative bearing swap now, since the replacement bearings are like to be better than the factory units (even if current bearings seem to work fine)...as long as its apart, 2 bearings maybe $15?.

If you decide to ventilate, I recommend spraying the inside with sealant to water-proof it (link in the thread below). And my personal favorite ventilation pattern is to put the holes near the rim on the chain side, and put the holes on the brake disc side near the axle. Then attach one of the 3D printed impellors. It seems counter-intuitive that air would go inside the housing near the rim, and then travel towards the center, but it works. The impellor flings air from the axle outwards, creating a low-pressure area inside the motor housing near the axle. Air flows in across the coils to get to the other side and then turns towards the axle.

The guy who is 3D-printing these impellors said that just adding ventilation holes ended up knocking ten degrees (fahrenheit) off his peak temps, and then when he added the impellor, that addition knocked another ten degrees off his peak temps. Not bad for a cheap and simple device that should last for decades with no maintenance? For max life I recommend 93C/200F as the limit at the stator, although...many have run their motors at a higher temp and survived.

If you are going to upgrade to thicker phase wires, I'd only want to do it once, so go as big as possible. LFP managed to squeeze in 10ga by employing extensive tricks, but personally...I'd go with Teflon-insulated multi-strand (Teflon is thinner than other common insulations, plus very heat resistant), 12ga through the axle, and 10ga outside the axle. If your amps overheat that, you need a bigger motor instead of fatter wires.

"DIY 10awg phase leads through axle in 9C hubmotor." (liveforphysics, 5 pages)
http://endless-sphere.com/forums/viewtopic.php?f=2&t=14580

"Definitive Tests on the Heating and Cooling of Hub Motors" (justin_le, 23 pages [includes links to many oil-cooling/ventilating-sideplates threads])
http://endless-sphere.com/forums/viewtopic.php?f=2&t=48753

"Oil cooling your hub- NOT snake oil!" (spicerack, 23 pages)
http://endless-sphere.com/forums/viewtopic.php?f=2&t=37972

"Temp sensor that's too cool not to share" (Auraslip, 4 pages)
http://endless-sphere.com/forums/viewtopic.php?f=1&t=25502

Well thanks for all the posts and tips I might consider them, but... I replaced the hall sensors, all very nice work, but still the same thing, will half ass run very stuttery, sometimes smooth, and then it will just cut out completely after two seconds of WOT (un-loaded). It was late lat night when I got it back together, so I will have to check this evening all the wires before the motor, to check for breaks in the wire. I will keep you updated.

Its always good to have a back-up controller. A sensorless 6-FET can be easily and cheaply found. Try one of those (purchased or borrowed) and if it works fine, the problem is not in the motor-phases, throttle, or battery

did you test the hall sensors before you decided to replace them? how were they tested?

the motor exhibits identical symptoms to those before you removed the original hall sensors?

I found the problem... wires where they enter the motor shaft... I did more testing and found one hall leg wire has been sheared somewhere inside the motor shaft. Check the pic.

So if I have to change the sensor wires, I may as well change the motor wires as well. However, only if the proper wire can be found locally.

can you verify which wire was cut? if you can strip off the sleeve on the outside. really you gotta cut it open and remove it, then find the wire that is severed, unsolder it from the hall sensor board so you can get some slack and pull just that one hall sensor wire through the axle enuff to solder the wire back together.

then splice in a jumper inside the hub to make up for the length of wire you pulled away from the hall sensor board.

use heat shrink and keep that chafing shield on it too if you can and then zip tie it back down to the stator and wrap your wires outside and put some big heatshrink back so it fits inside the axle hole to provide protection.

you need to take the 5 pin plug off to get the heat shrink down there too.

if you can do that then you could just leave it alone with no other wires broken. but then test the hall sensore with your controller and magnet before putting it back together for sure.

I think I should change the bearings out since the motor is open again, and I see one is definitely no good anymore, motor lead side bearing is still very smooth but it is still getting tossed. I think 12awg wire is what I will be using.

I have been playing around with all the leads, I CAN'T figure this out, could I have installed a defective HALL sensor? Check this out in the pic, can that small gap affect the sensor? I used a magnet to test them out, but I can't get it to switch, and I verified the wire continuity to each sensor as well.

Definitely harder bearings as those are fairly soft.

Gap makes no difference with your Hall sensor but if not switching something’s wrong?

It’s not too difficult to rig a test circuit directly to the component leads, bring your own 5VDC battery/supply (or thereabouts) maybe 10k pull-up resistor and test with magnet.

it should toggle when powered by the controller. it is not easy to kill a hall sensor unless you have a big voltage source, like the phase wires.

Okay, more testing, the one sensor lead (green) from the controller does not read 5.00volt like the other two signal leads, so it looks like this problem lies in the controller. I DID switch the bad signal lead with another sensor to verify the lead is bad. Should I attempt to open the controller up?

I wouldn't bother the controller until I could verify the Hall sensor component is working independent of the controller.

Read this thread here - http://endless-sphere.com/forums/viewtopic.php?f=3&t=57053&hilit=+hall+sensor+resistor

I posted some crude pics of how to do a component test and I suggest you try that before messing with the controller.

Found the problem for sure now... check out that broken little B@$!E&D inside there. Going to open it up and solder her in and use epoxy resin to secure the wires better.

I'm rebuilding a Motorino motor right now with some 10awg wires. This is the 4th hub motor I've rebuilt, all inspired by LFP's thread posted above.

Never thought to throw a temp sensor in there though...that's a brilliant idea. I have a few kicking around, I might as well while it's open.

Motors are hard to fix

so there was no need to open the motor at all?

why are your controller phase wires twisted like a rope where they come out of the controller?

looks like it got some serious twisting abuse there. no wonder the wire pulled loose inside the controller.

you need to set your camera to VGA so your pictures will fit on the thread. they are too big for this format.

It's just twisted after I opened it, they have always been straight. I really don't know why it broke, probably a bad solder... the whole thing isn't built very well to be honest.

this is good for us to get people to verify that it is the hall sensor itself first before opening the motor. so much hassle and they don't always go back together right, if they ever go back together at all.

you will find it impossible to get 10AWG inside, and the 12AWG is hard unless you have some thin insulation and the wires will lay straight inside the sleeve when you push it through. it think when they manufacture them they have a fairlead with something like the old chinese finger locks that squeeze down the end when they pull it through. they pull the entire encased cable too. you will find out what a hassle it is.

Hassle... down right impossible for me.

I put the original wires back in. Pics to follow.