Loss of power, no power

[Lessen]

I'm not very hip on my electric rc nitty gritty so I need some help.

I was running my M18 today when all of a sudden it seemed to be starting to lose power. Then, it didn't go at all from a dead stop. If I gave it a little throttle and nudged the car forward it would go.. but when I gave it some brake it didn't really brake.. it just coasted to a stop. Then it wouldn't go again with any throttle input. I brought it in and got a temp reading of around 145-150 on the can (actually the heat sink). The ESC was just warm to the touch so I don't think the problem is there. I don't think it's not a low battery cuz when I did get it to run when lifted, it still turned decent rpms. Besides, it was only like 10 minutes on the battery. Am I running the gearing to high? Did I damage the motor?

Xray M18
Novak Spy
Intellect 1400 6-cell
Trinity Monster termination (broke in according to MFG. specs)
42T spur
19T pinion

*edit*

Definately, not a low battery. I just charged it after it had cooled some and it peaked in less than 45 min. @ 1A

 

[HeartBreak]

It sounds like a broken brush. Take the springs off the endbell, and pull the brush out. Check to see if it comes out in one peice, or if it looks burnt.

 

[Lessen]

ok, how would I know if it's burnt.. I have no idea what a burnt brush looks like.

*edit*
Brushes are not broken.. the ends are somewhat grayed but I wouldnt say they look burnt, but I don't really know

 

[Rolex]

Do you have another motor laying around? It doesn't have to go in the car, but connected you should be able to tell if there's a problem with the speed controller.

 

[HeartBreak]

The only other thing I can think of that might be the cause of it is possibly a grounded wind on the armature, or maybe a bound up drivetrain. How does the car roll when you push it? It should roll with no effort at all.

edit; if the brush is burnt, it will look like charcoal, or come out in crumbly pieces. The only other real possibility is the brushes are worn out, or you have gotten oil on the comm, or maybe even dirt in the can.

 

[Lessen]

Do you have another motor laying around? It doesn't have to go in the car, but connected you should be able to tell if there's a problem with the speed controller.

yeah, I got another. I'll see if there is an issue. Unfortunately, I'll have to attempt to replicate the issue. I don't think it's the esc. It ran fine for 10 minutes.

The only other thing I can think of that might be the cause of it is possibly a grounded wind on the armature, or maybe a bound up drivetrain. How does the car roll when you push it? It should roll with no effort at all.

edit; if the brush is burnt, it will look like charcoal, or come out in crumbly pieces. The only other real possibility is the brushes are worn out, or you have gotten oil on the comm, or maybe even dirt in the can.

When you say roll do you mean with the motor engaged or no? When the motor is engaged, it sort of ticks when I push it.. but that's just the motor going through it's rev and catching the pull of the magnet. This is characteristic of this motor. I've had this motor before and actually had this same problem but I chalked it up to not being broke in properly. As far as being wore out... well, this motor is practically brand new. Today would be only the 3rd or 4th run on it since break in. Maybe this motor just sucks. I havn't run into this with the Mass Termination, only the Monster Termination. I'm going to run a 44T spur and 17t pinion tomorrow if it doesn't rain.. see what happens.

 

[Rolex]

I can't remember what it was called, but there was a commutator cleaner that was either dripped in or sprayed in, and you could instantly hear the RPMs go way up. Not only did it reduce the friction from the brushes, but also increased the conductivity. We even used it on our dremels. I'm sure one of the electric motor guys will know what I'm talking about.

 

[HeartBreak]

Simple every day motor spray does the trick. It's the same exact stuff that you can get at Napa. It's labeled as "Contact and electric motor cleaner". It'll set ya back a whoppin' $6.50 or so. Make sure you DO NOT get "Brake cleaner". Completely different stuff, it will eat the epoxy coating from the windings and cause a nice meltdown.

Also be careful to not get it on lexan. It will dry and crack the daylights out of it.

Anyways... You should feel a slight cogging effect (as the armature passes through the magnetic poles), but the car should roll smoothly and easily with little to no effort.

If it rolls with some resistance, it's possible you have a loose magnet. Did you hit anything particularly hard before the motor started to act up?

 

[robmob]

The same thing happened to my son when he ran a Spy with a Trinity Monster Termination motor. I put a Baja motor on that Ed had in his box and it worked fine with the Spy. The Trinity motor was new, no water or oil on the comm and the brushes were fine. Definitely not the Spy, but I don't know what the problem was.

Since the exact same symptoms are happening to you with the same motor and esc, clearly it is compatibility issue between the Spy and Trinity motor.

 

[Lessen]

Heartbreak- nope, didn't hit anything

Rob- The last time Ihad this motor it was in my Mini-T but I was running an XRS and it did the same thing. So maybe it's just a bad design.. if I were to guess I'd say it has something to do with contact or lack of.. maybe conductivity? Maybe when the motor gets too hot the current isn't getting across? Up untill today I've run this motor a couple times in my RC18 but I didn't have a problem then... maybe it IS a gearing issue.. getting too hot. Well, at any rate I've already changed a crapload of settings including gearing so maybe I'll have more luck tomorrow.

oh BTW, I just got everthing back together and turned it on.. gave it a tad of throttle and she spun no problem. :shrug:

 

[Lessen]

Update: no issues today

Ran it again today and fortunately did not have any power problems. The only loss of power was from a discharged battery. I took a motor temp as soon as the run was over and it was only 127-130. That's a good 20 degrees cooler than yesterday and I didn't even get the temp as quickly yesterday.. hell, that could reasonably be a 25 degree temp difference. I think problem solved.. for now.

 

[HeartBreak]

Sounds like you most likely had a gear mesh issue, or possibly some carpet fibers wound up on the axle.

Glad to hear ya got 'er runnin!

 

[Lessen]

no, definatley not gear mesh. I'm very anal about gear mesh. I know for a fact that wasn't it. I geared the car significantly lower for todays run.. I think that put a lot less strain on the motor and let it work more efficiently.. hence the lower temp. Just my opinion. At any rate, it ran a complete run with no problems

 

[HeartBreak]

That could be the cause of it... A simple over-gearing. The greying on the brushes sounds like a light glazing from heat.

 

[Lessen]

The greying on the brushes sounds like a light glazing from heat.

ahh. I'll watch out for that in the future.

*edit*
After reading that comment I decided to take another look at the brushes. It seems to me that they looked a little shinier after the 2nd run. So is this "glaze" possibly the beginning of a brush becoming burnt? I suppose that would explain what I hypothesized was lack of contact.

 

[robmob]

My sons problem was occurring in a Mini-T. It is possible that it was over geared. I never bothered to figure out what the problem was since it was the last straw for the Mini-T and I heaved it into a shoe box and got a 18T for him to race.

 

[bnrpat09]

I'm pretty sure you need new brushes, sound like your not getting power because the brushes are bad

 

[HeartBreak]

ahh. I'll watch out for that in the future.

*edit*
After reading that comment I decided to take another look at the brushes. It seems to me that they looked a little shinier after the 2nd run. So is this "glaze" possibly the beginning of a brush becoming burnt? I suppose that would explain what I hypothesized was lack of contact.

The glazing does contribute to a lack of contact. It's more of a carbon glazing. If you got that within 5 or 6 runs, I'd say the motor is over-geared by 2-3 teeth on the pinion, easily. You can clean it off with a CLEAN pencil eraser. Same with the comm, where the brushes contact. Just take a sharp straight pin to the grooves between the comm contacts afterwards to clean out the eraser dust.

A little carbon buildup is normal, but closer to about 20 runs, they should be acting up.