RCCrawler Forums

losikid · 09-09-2010, 08:31 PM

Ok now i think i figured it out but i want to know why. So i went out crawling to day and my rear motor seemed like it had hardley any power, and when full throttle it was making a whining sound, So i dealt with it for awhile, then it totally gave out, so i pulled each brush off f the comm then let it fall back down ( i pulled it up with the spring still on it), and it stopped whining. So what was causing this whining, its probably time to clean my motors but i ran out of cleaner and haven't had a chance to run down to the lhs.

ctracy · 09-09-2010, 08:35 PM

i'd say there is dirt or something not allowing tension to be released on the brush or causing too much tension on the brush. could be wrong but if you pulled them out and snapped back in and the noise stopped then I would say that's what caused the issue. in a pinch i have used rubbing alcohol.

edit: I would listen to eddie he knows what he is talking about.

EddieO · 09-09-2010, 09:24 PM

How long are the brushes still? Has the comm been cut?

Unfortunately, just spraying out the motor doesn't do much once the brushes get short and the comm starts getting grooved......

More than likely, a cut and new brushes will cure your problems.

Later EddieO

losikid · 09-10-2010, 07:35 AM

Quote:

Originally Posted by EddieO

How long are the brushes still? Has the comm been cut?

Unfortunately, just spraying out the motor doesn't do much once the brushes get short and the comm starts getting grooved......

More than likely, a cut and new brushes will cure your problems.

Later EddieO

They are 35t r/t warriors, i just bought them not too long ago so the brushes and comms should still be good, although they do run pretty hot since their on an losi moa, but i would hink they'd still be good. About how many hours can i run motors before they need to be cut. I'll pull the brushes out tonight and see the condition of the comm and look at the length of brushes.

TEDROCKZ · 09-10-2010, 08:24 AM

Quote:

Originally Posted by losikid

They are 35t r/t warriors.

Br00d built!.

Most motors will fall off in performance due to brush wear, springs losing tension, comms need truing or just plain dirty. It will be noticeable in loss of go, drag brake and effeciency.

New brushes and springs, a comm truing and a good cleaning(be sure to clean inside the brush hoods really good. I use Lysol tub and tile cleaner,works wonders! That is where most of the current flows to the brush. Not the shunt wire!) If available a good magnet zapping will be great as well. After rebuilding break the brushes in right and let her eat!!!

EddieO · 09-10-2010, 08:37 AM

Well, really, you guys should be rebuilding your motors a lot more often than you do...

In racing, we would rebuild after every run at big races and after each race day at local stuff, though some did the every run thing at the week night racing too.

A local guy, who is just a hobbyist, doesn't compete has been bring his motors to rebuild. He has a set of mine, a set of banazi and a set of fantoms, all used on the same bully based crawler he bought. I've been having to rebuild his stuff every 10 packs or so.....

I've been rebuilding my Losi crawler motor a lot more often than other crawlers. The truck is cool, but its a lot easier to be hard on the motor with it because of the axles....

My berg is almost done and I will be rebuilding my motors before each comp...

At worst, you can send the motors in......I'll rebuild them just for the cost of the brushes (2.50) and the shipping back....

Later EddieO

TEDROCKZ · 09-10-2010, 08:52 AM

Quote:

Originally Posted by EddieO

Well, really, you guys should be rebuilding your motors a lot more often than you do...

True! lot cheaper than ruining a 50-60 buck motor. as well as keeping performance up!

Quote:

Originally Posted by EddieO

I've been having to rebuild his stuff every 10 packs or so.....

Bout what i average. But I just like doing it. Professional tinkerer

Quote:

Originally Posted by EddieO

At worst, you can send the motors in......I'll rebuild them just for the cost of the brushes (2.50) and the shipping back...

losikid · 09-10-2010, 08:56 AM

my front motor is doing way better though, which is the motor i beat on the most, its always hot, the rear motor hardly ever warm. I think my lhs lathes motor for cheap and replaces the brushes. Do think he has a magent zapper though. Also wouldn't lathing a motor too much cause it to lose power since your taking some of the comm away.

TEDROCKZ · 09-10-2010, 09:06 AM

Quote:

Originally Posted by losikid

Also wouldn't lathing a motor too much cause it to lose power since your taking some of the comm away..

If you stay on top of maintenance you are not taking off but a few thousandths per truing. Running a motor that needs truing for long periods will cause you to have to cut it that much more per rebuild.

All motors wear out, you can control the rate of that though.

losikid · 09-10-2010, 09:10 AM

Ok, well i'm looking into buying a lathe haven't quite wanted to yet because i want to see how well the new brushless motors jrh is making are going to turn out, a brushless moa would be awesome, then i won't need a lathe. I'll proably have the lhs cut my comms and replace the brushes, should by buy some special ones for him to use or are all the brushes the same, (not sure which ones he has)

EddieO · 09-10-2010, 09:25 AM

In theory, as the comm gets smaller, the motor will gain RPM, but lose a tad amount of torque (we are talking very small amounts), but the loss of torque is outgained by the RPM gain, so the motor actually gains power....at big races, we would often cut the stock and 19t arms down to fairly small sizes to gain extra power....

Tedrockz is right, if you rebuild a little more often, its not uncommon for much smaller cuts to be made on the comm.

While, I am not sure which warrior you have, its more than likely a 9mm or 10mm comm version, which have plenty on copper, so you can do cuts for a while......when the arm is done, you buy a new one and install.....no different than tires, bodies, etc...

Rear motors get subjected to lots of weird stuff.....from weird throttle to digs, its not suprising we see rear motor problems first. I rebuild about 2-3 pairs of motors a week, most of which are not even motors from me(Banazi, Trinity, Fantom, JPH, HH, Integy).....and on all them (including mine) its been pretty common to see the rear motor looking more nasty than the front....

Later EddieO

yjdavid · 09-10-2010, 10:06 AM

can the armature be chucked up in a normal lathe and have the comm cut that way rather than a dedicated comm lathe? All you're doing is take material off of it correct? And the time to stop taking the material off is when the comm is completely even? How much would one expect to turn down (thousandths wise)?

EddieO · 09-10-2010, 11:36 AM

Sure can.....that's how Big Jim cut all his arms, in an older emco lathe. Reedy used a really cool one that was automated with air power....was very trick. I originally did it like Big Jim too, but comm lathes were simply faster and gave just as good of a cut....

Later EddieO

losikid · 09-10-2010, 12:22 PM

I'm on am maching class now, i'm not going to, but what would happen if i mounted up a armature and lathed the comm on a full size lathe. I have the warrior r/t if it is the biggest comm either a 10 or 11mm i can't remember

EddieO · 09-10-2010, 12:46 PM

As long as you mount it up correct, so you don't knock is out of balance, you will be fine....

Just make sure you have a similar style cutting tool like what we use (reedy and big jim used the exact same tools our little lathes do)....

In the end, you are just cutting copper.....which is basically considered a butter metal....

Warrior R/T should be a 10mm comm

Later EddieO

EeePee · 09-10-2010, 03:38 PM

Quote:

Originally Posted by TEDROCKZ

If you stay on top of maintenance you are not taking off but a few thousandths per truing.

I got to a point where I was cutting the motor in the Losi before every event, and running it for only three courses, so maybe at most 15 minutes. I would make just one single pass with the lathe, and it was just a skim at most, so not even a few thousands. Like, half a half of a half of one thousandth.

Clean is power.

losikid · 09-10-2010, 04:38 PM

so your saying.00025 or an inch Thats small. Are motor lathes really that accurate. The big lathes i've been suing are only accurate to .001, well the dials are, accurate compared to the calipers its more like accurate to .005-.010. Really bugs me when thats the same as our tolerances we have to be in,

EeePee · 09-10-2010, 05:12 PM

Iiiiiiiiiiiiiii don't know how exactly small... my point was I'm taking off the smallest amount possible, but completely cleaning off the commutator surface with just one single pass. I do motors that guys beat on and completely neglected all maintenance and it might take 10 or even 15 passes at a third of a thousandth each pass.

Let's say it takes me 15 passes to get a completely clean comm, cutting off 1/3 a thousandth every time. That's 5 thousandths total removed. Compared to mine taking a single pass, say a total of 1/3 of a thousandth removed. I can have a fresh cut comm 15 times (more power) compared to not taking care of it, and running it into the ground, losing performance every run, then needing a large amount to be removed to work its best again.

I get fifteen clean motor runs, they get one.

Clean is power.

TEDROCKZ · 09-10-2010, 05:18 PM

Quote:

Originally Posted by EeePee

I do motors that guys beat on and completely neglected all maintenance and it might take 10 or even 15 passes at a third of a thousandth each pass.

I'm gonna do a pair for Austin that has been on his rig for an entire season, just changed them out for newer ones. You all know how delicate he is on stuff...Should be interesting!!!

EeePee · 09-10-2010, 05:42 PM

Yeah, first thing I would do is measure the comm diameter and see if there's anything left to take off.

09-09-2010, 08:31 PM	#1
losikid Got Worms? Join Date: Jun 2009 Location: Golden, CO Posts: 6,116	Motor Whining Ok now i think i figured it out but i want to know why. So i went out crawling to day and my rear motor seemed like it had hardley any power, and when full throttle it was making a whining sound, So i dealt with it for awhile, then it totally gave out, so i pulled each brush off f the comm then let it fall back down ( i pulled it up with the spring still on it), and it stopped whining. So what was causing this whining, its probably time to clean my motors but i ran out of cleaner and haven't had a chance to run down to the lhs.

09-09-2010, 08:35 PM	#2
ctracy Quarry Creeper Join Date: Jul 2010 Location: Independence Posts: 368	i'd say there is dirt or something not allowing tension to be released on the brush or causing too much tension on the brush. could be wrong but if you pulled them out and snapped back in and the noise stopped then I would say that's what caused the issue. in a pinch i have used rubbing alcohol. edit: I would listen to eddie he knows what he is talking about. Last edited by ctracy; 09-09-2010 at 09:26 PM.

09-10-2010, 08:56 AM	#8
losikid Got Worms? Join Date: Jun 2009 Location: Golden, CO Posts: 6,116	my front motor is doing way better though, which is the motor i beat on the most, its always hot, the rear motor hardly ever warm. I think my lhs lathes motor for cheap and replaces the brushes. Do think he has a magent zapper though. Also wouldn't lathing a motor too much cause it to lose power since your taking some of the comm away. Last edited by losikid; 09-10-2010 at 09:01 AM.

09-09-2010, 09:24 PM	#3
EddieO I wanna be Dave Join Date: Apr 2007 Location: Arlington, Washington Posts: 2,303	How long are the brushes still? Has the comm been cut? Unfortunately, just spraying out the motor doesn't do much once the brushes get short and the comm starts getting grooved...... More than likely, a cut and new brushes will cure your problems. Later EddieO

09-10-2010, 08:37 AM	#6
EddieO I wanna be Dave Join Date: Apr 2007 Location: Arlington, Washington Posts: 2,303	Well, really, you guys should be rebuilding your motors a lot more often than you do... In racing, we would rebuild after every run at big races and after each race day at local stuff, though some did the every run thing at the week night racing too. A local guy, who is just a hobbyist, doesn't compete has been bring his motors to rebuild. He has a set of mine, a set of banazi and a set of fantoms, all used on the same bully based crawler he bought. I've been having to rebuild his stuff every 10 packs or so..... I've been rebuilding my Losi crawler motor a lot more often than other crawlers. The truck is cool, but its a lot easier to be hard on the motor with it because of the axles.... My berg is almost done and I will be rebuilding my motors before each comp... At worst, you can send the motors in......I'll rebuild them just for the cost of the brushes (2.50) and the shipping back.... Later EddieO

09-10-2010, 09:10 AM	#10
losikid Got Worms? Join Date: Jun 2009 Location: Golden, CO Posts: 6,116	Ok, well i'm looking into buying a lathe haven't quite wanted to yet because i want to see how well the new brushless motors jrh is making are going to turn out, a brushless moa would be awesome, then i won't need a lathe. I'll proably have the lhs cut my comms and replace the brushes, should by buy some special ones for him to use or are all the brushes the same, (not sure which ones he has)

09-10-2010, 09:25 AM	#11
EddieO I wanna be Dave Join Date: Apr 2007 Location: Arlington, Washington Posts: 2,303	In theory, as the comm gets smaller, the motor will gain RPM, but lose a tad amount of torque (we are talking very small amounts), but the loss of torque is outgained by the RPM gain, so the motor actually gains power....at big races, we would often cut the stock and 19t arms down to fairly small sizes to gain extra power.... Tedrockz is right, if you rebuild a little more often, its not uncommon for much smaller cuts to be made on the comm. While, I am not sure which warrior you have, its more than likely a 9mm or 10mm comm version, which have plenty on copper, so you can do cuts for a while......when the arm is done, you buy a new one and install.....no different than tires, bodies, etc... Rear motors get subjected to lots of weird stuff.....from weird throttle to digs, its not suprising we see rear motor problems first. I rebuild about 2-3 pairs of motors a week, most of which are not even motors from me(Banazi, Trinity, Fantom, JPH, HH, Integy).....and on all them (including mine) its been pretty common to see the rear motor looking more nasty than the front.... Later EddieO

09-10-2010, 10:06 AM	#12
yjdavid Rock Crawler Join Date: Oct 2009 Location: SO CAL Posts: 598	can the armature be chucked up in a normal lathe and have the comm cut that way rather than a dedicated comm lathe? All you're doing is take material off of it correct? And the time to stop taking the material off is when the comm is completely even? How much would one expect to turn down (thousandths wise)?

09-10-2010, 11:36 AM	#13
EddieO I wanna be Dave Join Date: Apr 2007 Location: Arlington, Washington Posts: 2,303	Sure can.....that's how Big Jim cut all his arms, in an older emco lathe. Reedy used a really cool one that was automated with air power....was very trick. I originally did it like Big Jim too, but comm lathes were simply faster and gave just as good of a cut.... Later EddieO

09-10-2010, 12:22 PM	#14
losikid Got Worms? Join Date: Jun 2009 Location: Golden, CO Posts: 6,116	I'm on am maching class now, i'm not going to, but what would happen if i mounted up a armature and lathed the comm on a full size lathe. I have the warrior r/t if it is the biggest comm either a 10 or 11mm i can't remember

09-10-2010, 12:46 PM	#15
EddieO I wanna be Dave Join Date: Apr 2007 Location: Arlington, Washington Posts: 2,303	As long as you mount it up correct, so you don't knock is out of balance, you will be fine.... Just make sure you have a similar style cutting tool like what we use (reedy and big jim used the exact same tools our little lathes do).... In the end, you are just cutting copper.....which is basically considered a butter metal.... Warrior R/T should be a 10mm comm Later EddieO

09-10-2010, 04:38 PM	#17
losikid Got Worms? Join Date: Jun 2009 Location: Golden, CO Posts: 6,116	so your saying.00025 or an inch Thats small. Are motor lathes really that accurate. The big lathes i've been suing are only accurate to .001, well the dials are, accurate compared to the calipers its more like accurate to .005-.010. Really bugs me when thats the same as our tolerances we have to be in,

09-10-2010, 05:12 PM	#18
EeePee MODERATOR™ Join Date: Jul 2004 Location: Ohio Posts: 18,928	Iiiiiiiiiiiiiii don't know how exactly small... my point was I'm taking off the smallest amount possible, but completely cleaning off the commutator surface with just one single pass. I do motors that guys beat on and completely neglected all maintenance and it might take 10 or even 15 passes at a third of a thousandth each pass. Let's say it takes me 15 passes to get a completely clean comm, cutting off 1/3 a thousandth every time. That's 5 thousandths total removed. Compared to mine taking a single pass, say a total of 1/3 of a thousandth removed. I can have a fresh cut comm 15 times (more power) compared to not taking care of it, and running it into the ground, losing performance every run, then needing a large amount to be removed to work its best again. I get fifteen clean motor runs, they get one. Clean is power.

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09-10-2010, 05:42 PM	#20
EeePee MODERATOR™ Join Date: Jul 2004 Location: Ohio Posts: 18,928	Yeah, first thing I would do is measure the comm diameter and see if there's anything left to take off.

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