Front end not pulling, well sometimes.

[irokcrawl]

during this past weekends comp I noticed that my front end would not pull unless the rear pushed it enough to get it to roll a little. I could pick it up and put the front tires up against something and they would not turn, I could then push the front tires so they would turn a little and then they would start turning. My setup is dual sidewinder micro's that have been calibrated correctly, a set of one off 35 turn handwound Br00d motors, CCBEC, Futaba 4pks and a flysky rx until I get my Futaba 614ff back. I do not have another rx to try but I don't know if that would cause the problem or not. I'm going to swap the front and rear esc's at the rx to see if that changes anything when I get back to the rig tonight. Also nothing on the 4pks has changed since I swapped in the sidewinders after I burnt up the micro mamba pro's. Anyone have any idea's? I may can get some video of it tonight around 11pm central time if that would help.

[TEDROCKZ]

Sounds to be a hanging brush or dirty comm.

[Speedracer19]

Originally Posted by TEDROCKZ

Sounds to be a hanging brush or dirty comm.

That is what it sounds like.

[EddieO]

A. Hung Brush or Nasty comm
B. Shorted Armature

Rebuild the motors (comm cut, new brushes).....if problem stays, you shorted the armature. It happens, nasty binds can do bad stuff to even the best motors.

Later EddieO

[irokcrawl]

O k. I'll turn the motors down on a lathe and put new brushes in it to see if that changes anything. These are the motors I asked EddieO and Tedrockz about about a 2 weeks ago. They were the "Crawler" motors.

Sent from my DROID RAZR using Tapatalk 2

[losiking1]

What kind of time are on your motors??

[irokcrawl]

Originally Posted by losiking1

What kind of time are on your motors??

They are timed on the marks on the cans and I don't think they have any added timing. I haven't changes that. These were owned by a few others before me.

Sent from my DROID RAZR using Tapatalk 2

[TEDROCKZ]

Originally Posted by losiking1

What kind of time are on your motors??

Originally Posted by irokcrawl

They are timed on the marks on the cans and I don't think they have any added timing. I haven't changes that. These were owned by a few others before me.

Sent from my DROID RAZR using Tapatalk 2

I think he is referring to run time. They are probably about due for a freshening.

[hbj069]

True and considering the dead short that took out the two esc's and the receiver Last week it may have definitely shorted the armature!

[irokcrawl]

Originally Posted by hbj069

True and considering the dead short that took out the two esc's and the receiver Last week it may have definitely shorted the armature!

That was on the rear motor though. The front wasn't the one that shorted out. I may see if nick will let me borrow his lathe and turn them a little. What would resolve the issue if the arm was shorted if there is one?


Sent from my DROID RAZR using Tapatalk 2

[irokcrawl]

Originally Posted by TEDROCKZ

I think he is referring to run time. They are probably about due for a freshening.

Ha that would make more since. They needed turning but I stuck them in there just to see what they would do. I need to change the pinions anyways to gain some more wheel speed so no problem to pull and freshen them up some.

Sent from my DROID RAZR using Tapatalk 2

[JohnRobHolmes]

A new armature would be the fix for a dead arm. You can find a dead arm with a multimeter, no continuity between two or more segments of the comm. Try that before cutting them down, you will likely save yourself some time. If there is a dead segment, inspect it carefully for a visual break in the wire (if you care). Going back through my bins of dead arms I found that 100% of the open circuit arms had breaks at the termination point that weren't visible at first glance. I used to think it was an internal issue and I drove myself mad unwinding them trying to find it! You can find a shorted arm by testing continuity between the stator steel and the commutator. It is very rare, and a normal arm will not have continuity between the laminations and the comm. A third possible issue could be that you have contaminates in your comm segments causing a short. If the motor won't free spin with the brushes removed, clean out the comm gaps and try again. This is more frequent when high silver content brushes are used as it sticks a bit more than copper and graphite.

[hbj069]

Originally Posted by irokcrawl

That was on the rear motor though. The front wasn't the one that shorted out. I may see if nick will let me borrow his lathe and turn them a little. What would resolve the issue if the arm was shorted if there is one?


Sent from my DROID RAZR using Tapatalk 2

It created a dead short trough the entire system otherwise you would have only smoked 1 esc instead of both, by squeezing the throttle trying to make it move the brushes become welding rods to the armature creating burn spots. 11 volts to the armature and it not spinning may have created the short as jrh described at a connection point on the armature. Best to let Tedrockz (if he will) take them with him and go through them properly.

[ManxCrawler]

Sounds like one of the brushes has worn to the point the spring is resting on the end of the slot in the hood and not supplying pressure to the brush on the comm

[TEDROCKZ]

Originally Posted by hbj069

Best to let Tedrockz (if he will) take them with him and go through them properly.

Best I can do is try to diagnose the problem. If it's a simple fix like brush or dirty comm issues I can fix you up. If it's an arm short you can order a new one and I'll reassemble it. IIRC those motors or @ 2years old but not much run time on them. I was unaware of the ESC issue so it may be a short...

In the long run it may be just easier to send them both to Eddie(og builder of it) or John. If you have to re-armature them both they are still worth the $. KRs are hard to come by.

[JohnRobHolmes]

Thats the nice thing about a rebuildable motor, you can keep them running for years and years with an arm and brush change. As long as they don't get beat on the rocks too hard!

[hbj069]

true, pull them out and put the jrh's back in, I will meet up and take them to Ted Sunday and we can go from there..

[irokcrawl]

Originally Posted by hbj069

true, pull them out and put the jrh's back in, I will meet up and take them to Ted Sunday and we can go from there..

Will do. They had tons of tq and I think I would have finished a few courses if I would have noticed it at the beginning of the day and swapped motors. I was wondering why my ass end was being pushed around the rock before it started to climb the rock. Once they are turning it doesn't act up until I stop again at a ledge. I'm looking forward to running these when they are working properly. I guess I messed up every single thing in the rig besides the servo. That was an expensive lesson :homer:

Sent from my DROID RAZR using Tapatalk 2

[concretejungle]

i posted this in another thread like this when i had the same type of issue. i found out that my pinion gear set screw had come loose. The pinion gear was spinning on the shaft when a lot of bind was on it. Tightened up the set screw and it's all good.

[irokcrawl]

Originally Posted by concretejungle

i posted this in another thread like this when i had the same type of issue. i found out that my pinion gear set screw had come loose. The pinion gear was spinning on the shaft when a lot of bind was on it. Tightened up the set screw and it's all good.

I had thought about that but I have not opened it up yet. I always put thread lock on that set screw but anything is possible. I will check that tonight.

Sent from my DROID RAZR using Tapatalk 2