best circlips to use for shafts?

[Dillzio]

Hi all, quick question.

What is the best type of circlip to use for a motor shaft?

The little one on the left (under the plastic) that came with it, or the larger one on the right that I also purchased from the same spot?

cheers

[NorCalAirman]

Mine came with one like on the left and it got mangled coming off. I replaced it with one like you have on the right from a Traxxas assortment bag. I haven't flown yet, but in ground tests it has held 100%. My only concern is that it's a bit thicker than the original, not sure if that's your case. It seems much sturdier though.

Either way, total PITA to get them off and on, at least it was for me.

[Dillzio]

yeah, the other ones are thicker, i had to move the shaft out of the bell a fraction more for them to fit properly.

I'm having another problem now...

The reason I've changed the prop shaft is that since a bit of a rough landing a while back, my outrunner has been making a bit of a buzzing noise, like there's something inside it rubbing, pretty much like what was happening with my last motor here but not as bad... www.youtube.com/watch?v=6ghOgqoULWA
It hasn't really been causing any problems (that I've noticed) so I've just been living with it.

Anyway, I assumed the shaft must be a little crooked making one of the magnets on the bell rub on one of the stators, but when I opened it up I found no evidence of anything rubbing. I decided to change the shaft anyway, and now that I've got it back together again it's still making that rubbing noise. I've also noticed that even with NO PROP on at all, at WOT the base of the motor gets too hot to hold within 1 min! I lubed up the shaft and bearings with petroleum jelly before I put them in so lubrication should not have been an issue. I'm not sure if it was getting hot like this before I changed the shaft because when I check if the motor's hot I only check the rotor, not the base.

Could this be caused by a bearing that needs replacing? The shaft was REALLY hard to get in at a few points, and it's hard to get out too. Does any of these signs point to shot bearings?

[flydiver]

Easiest way to find shot bearings is take the motor apart, stick a pencil point in the bearing hole and spin by hand. Should be smooth and easy. Rough indicates brinnelling (dents in the race from impact). Resistance to turning indicates totally shot.
You can brinnel a bearing simply by letting the stator get away on assembly and slam into the bell. They don't like side loading at all.

The shaft should 'usually' slide in an out of bearing easily. If not it may be bent. Bent only a couple thousands is not good and is amazingly easy to do with a good impact.

Hot....obviously is not good. You may have a short in one of the tiny winding wires.

IMO either clip will work but the larger right one is easier to deal with. I hate the left type.

Petroleum jelly? That what we call grease? You won't be able to get it inside the bearing. Use a quality light oil (sewing machine, thin motor oil, etc.) Don't know if you have it there but NOT WD40.

[Dillzio]

Thanks fly.

What do you mean by a short in the wiring wounds?
Do you mean two of the wounds touching each other, because it pretty much looks like they all are.

I've found now that both bearings seem to have a dent somewhere in their internal mechanism so they don't spin smoothly, now I know that's the same thing that happened on my last motor. The shaft gets a bang to the side but it's stopped from moving by the bearing that ends up getting it's internal rollers dented by the heavy knock, it all makes perfect sense now.

I'm wondering if maybe dodgey bearing could be the problem, is it common for bearings to put out a lot of heat when they're not working well? Neither bearing has ceased, both spin OK, just have a bit of a rattle to them and not very smooth, but at 10,000rpm i'm wondering if friction could be building up to produce all that heat?

Petroleum jelly is a type of grease, I think some call it white grease, or vasoline. I was worried it might be too thick to penetrate the bearing as well, but once it heated it up it melted and pretty much soaked into everything. I'll see if I can find a bearing shop tomorrow and pick up some replacements.

[flydiver]

The winding wires have a hard plastic coating. This coating can get damaged, poor winding technique, dirt/junk in the motor that gets ground in by spinning, manipulating the wires where they come out and causing them to break all can do it. Most motors are wound with a bunch of tiny wires so you can break a single one and still have it work but not properly. Often broken wires cause a motor to stutter and not run at all.

A bearing would have to be pretty stuck to not run and you should be able to feel that with the pencil technique. They'll run with dinged bearings but generally make a sound that's not right. The brinnel dents are like pot holes > they just get worse. I've run them a good while that way if they aren't too bad and kept oiled. I've also had them literally disintegrate while being used, luckily in a low power cheap motor (Tower Pro-they use crap bearings)

No idea where you might get replacement bearings. There are sources in the states but often it seems that the cost + shipping exceeds the value of the (cheap) motor.

Getting the bearings out of their slot is sometimes difficult and causes complete destruction. You need to be very careful about putting them back in to not damage the races.

Here's some good videos on motors:
www.innov8tivedesigns.com/#PS

[Dillzio]

Thanks for the info fly!

Further testing has revealed that there is a short somewhere in the motor that is producing all the heat. I confirmed this by running the motor without the bell on it, and it still drew over 10 amps and got quite hot.

Would you happen to have another of those handy video tutorials up your sleeve on how to respool a motor?


...or is it normal for the stator to get hot if it's energised without the rotor on it? I just tested my old outrunner and with rotor it drew 2 amps, without it maxed out!

[flydiver]

Uh, how do you RUN an outrunner without the bell? That's just a dead shorted stator. I think ANY motor would get hot, even a good one as you demonstrated. I've never tried it.
An un-propped motor won't draw very much if operating properly.

If you want to test for shorts the simple way is to remove the bell. Get a digital voltmeter and put in in [OHMS]. Put one lead on a motor lead and the other on a bare part of the stator. You should get no reading (infinite resistance). Do that with each motor lead and make sure you press hard and scratch on the stator for a good connection.
There are other methods but are more complicated. I seldom use them as this one generally is enough.

Not a good motor to start with winding. It would be intermediate > advanced. You have to get the stator off the bearing shaft (glued on) and the windings off-probably also glued on. After trying a few of those kind of motors I threw in the towel (actually threw the motor) and do mostly easy bell type winds. It's a PITA getting some apart, not worth my effort.

If you do want to learn more you can watch this:
www.youtube.com/watch?v=_6-BUfNYCEU
It's interesting but not enough info.

This is a good way to start:
A GBv or GBx kit: www.gobrushless.com/shop/index.php?app=ccp0&ns=catshow&ref=diy+brushless+kits
Then read the tutorial link (left side).

I don't suppose it's worth the postage for one of those kits but there might be something similar in Oz.
These are good candidates for rewinding-you just need wire and practice:
www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=2069
www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=8617

Or get someones busted TowerPro bell motor. They are easy to come by, generally free, and pretty easy to wind. Most of them are dLRK wind (9 stator poles, 14 magnets) like the motors linked above. The 2408-21 and those gobrushless kits are ABC wind, which is easier at first.

If you truly get interested I will give you some links.

FWIW-like flying you re-wind mostly for fun. You do learn a lot about motors, props, power, etc and you can end up with a better motor, sometimes much better. It is not cost effective.

[ginginho]

Is it not a possibility that the short exists between the windings? If this is so, you need to check (with your meter set to ohms again) between each of the three inputs. There should be no connectivity.

[flydiver]

Apr 19, 2011 12:14:48 GMT 1 ginginho said:

Is it not a possibility that the short exists between the windings? If this is so, you need to check (with your meter set to ohms again) between each of the three inputs. There should be no connectivity.

That doesn't work-the windings are electrically connected. That's why there is a dead short when the motor is stopped as in a crash or won't run because of a broken wire.

Take a look at the delta and star termination methods for motors.
www.rcgroups.com/forums/attachment.php?attachmentid=2368527

[ginginho]

Apr 19, 2011 15:51:50 GMT 1 flydiver said:

Apr 19, 2011 12:14:48 GMT 1 ginginho said:

Is it not a possibility that the short exists between the windings? If this is so, you need to check (with your meter set to ohms again) between each of the three inputs. There should be no connectivity.

That doesn't work-the windings are electrically connected. That's why there is a dead short when the motor is stopped as in a crash or won't run because of a broken wire.

Take a look at the delta and star termination methods for motors.
www.rcgroups.com/forums/attachment.php?attachmentid=2368527

Yeah, of course it is, my mistake.
I was thinking back to when I attempted a rewind, this can be done after winding but before the ends are connected up.