get the ones with the replacable brushes

ive only melted out about 3 motors, jake has hacked apart most of mine now so i might get a photo fest of the brush housings and armatures.

most failures ive had in accordance with the keros is with the brushes parting company with the motor and landing outside the can somewhere and also with the brush "tab" bending off the armature.

the fan melting is also a less common problem but its happened before.

ive also seen the bushings melted, rotating in their sockets and flat out siezed. this is one aspect the hobby motors would shine in, decent ball bearings. alot of the hobby motors are also made to be rewindable so that would be quite easy.

maybe jake should post about the drill motor he rewound with half the number of turns. it really had a ton more torque as it jumped out of your hand but also had the tendancy to get too hot to hold in a few seconds

rewinding a drill motor would be basically impossible IMHO because its so hard to remove the tabs holding the end bell on. most times they have to be dremeled off
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The tabs on the 18V DSE drills are a little better; I was able to easily bend them with pliers. The armature is all stripped & waiting for some 24 awg wire to be wound back on. The brushes on this motor are very poor, with only about 1/5 of the surface contacting the comutator. If I file them very carefully, they may perform better (or I might have to get another broken motor and start over )
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I just split this thread out of the "just wondering" thread, since its developing into quite an interesting and sustained little topic on its own, so it didnt really belong there anyway..

carry on people..
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Great minds discuss ideas. Average minds discuss events. Small minds discuss people

took 3 photos for yall, my camera doesnt have the greatest zoom so forgive the quality..

the first one shows a part of the burnt out armature, the charred black bit (you dont say lol). all my burnt out motors only are melted in this area, in between those pole pieces. funnily enough this motor had the brushes intact and if the wires had merely melted off the insulation i would have thought it would still run but just terribly? no?

http://photobucket.com/albums/v357/Cobrarobotics/Dewalts%20and%20motors/?action=view&current=DSC01490.jpg

the second one is with a brush holder on an xu1. as you can see the brush tab has just blown off and snapped totally, it was like that when i took the motor apart. the part where it attaches to the plastic end bell is also blackened and bubbled.

http://photobucket.com/albums/v357/Cobrarobotics/Dewalts%20and%20motors/?action=view&current=DSC01492.jpg

this third one is definitely the most spectacular blowout cobras ever had. the brush tab has blown off one end, part of the brush has melted onto the end cap in the top right corner and the other part has landed on the top left (its the BIG peice).

http://photobucket.com/albums/v357/Cobrarobotics/Dewalts%20and%20motors/?action=view&current=DSC01493.jpg

the top picture shows how that fan is just slotted into the pole pieces. given its a source of failure i would definitely remove it if posed with the need to take the motor apart. i guess it would make the motor accelerate harder with less mass to spin up (high in technical wank factor that part is )

and i think the brush problem could be solved by basically filling in the area behind the brush tabs with epoxy. it would stop the tabs bending off and brushes blowing out the back of the tabs. or put a spring behind them to allow the brushes to move in and out as in addition to stopping them bending back.
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That beats all my efforts, my fans just melted & jambed the armature . I wonder why the vent holes are not larger? The amount of metal on the back of the motor is way more than enough to support the brushes.

The wire needed to rewind the motors is only $4.95 from Jacar so even if I never use the motors, its interesting enough to try for it's own sake.
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Australian 2015 Featherweight champion
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I can't remember where they are, but I have a pair of RS-550's with metal endcaps, not plastic. I think I damaged one of them when the fan melted. Can't remember if they were from compressors or drills
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The DSE 18V drills have metal ends with plastic insulation underneath. They hold the rear bearing better when things get toasty, but ultimately, the fans melt just as easily

The aftermarket motors have all the comutator area out in the open to radiate heat better - a much better design.
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UK 2016 Gladiator champion

my old kk2 9.6v drills have metal endcaps. i think stepping up to proper bearings inside the motor itself would make for a huge improvement. the fact that the bearings melt out of the housings means that those things are getting way too hot and overloaded.
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Sure the bearings melting out of the casing isn't because of the extreme temperatures produced by an overvolted armature?
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yeah I'd be blaming the hot armature for melting the bearing carriers.

There's not much surface area there to dissipate the heat, and since the plastic's a decent insulator the bearing will just heat up till it melts a larger hole, then it'll start spinning in the plastic!

Feel the end of the shaft after even a pretty short run and it'll be quite hot.
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The Engine Whisperer - fixer of things

Quick Question, before I destroy something valuable. If I was to dip the armature of my RC car motor into kerosene to clean it, would this deteriorate the insulation on the windings?

Also, is it okay to give the brushes a bit of a swim too
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ive dipped my xu1s into kerosone a couple of times to clean them. and i also did it with either turps or metho.. cant remember which one but i dont recall anything bad happening with them. (until i ran them at 24v of NIMHs with some tractile tires and they blew the brushes.)
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mm i hope after diping then in kerro and drying them you rembered to put a drop of light machine oil on the shaft near both bearings so it will soak into the bronze bushes ...if not the bearing will definatly sieze up

Also the problem with cooling these motors isnt the size of the vent holes but the way the motors are mounted on the drill houseings .
The front air intake holes are nearly blocked up by the drill gear boxand once a tight fitting plastic mount is slid on the motor against the gear box it basicly blocks them right off
So the motor realy isnt geting cooled by the fan any way .The only way to realy help the problem with out removeing the fan is to put some more vents in the front of the motor or slots in the mounts to alow air flow .The fans on these motors are centrifical and basicly are desighned to pull the air through the motor between the armeture and the magnets then exaust it out of the vent holes.
I usualy take the motor off and slot the plastic drill case near the motor vent holes allow more air flow .
We Havent burnt out any drill motors yet ..we did burn a few compresor motors out but that was because we had about 4.8 to one gearing so the motors very rarely got up to high revs useing the speed controlers so were probaly running close to stall current most of the time ..Also one thing i have thought of doing but havent tried yet was to drill two small holes in the motor end cap this would alow a small flow of air around the brushes and comutator especialy if the hole could be directed at the brush holders.

http://www.rcboatmodeler.com/pdf/MEGA_MOTOR_GUIDE.pdf

great guide to hobby motors if your looking at retro fitting them into the drills. was going to put it in the ultimate guides but seems i cant.
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