My Bomber is smoking motors

[k0Re7]

So it sounds like i either need to get a 550 21t titan or get a 10 tooth pinion gear and stay with a 540 motor. i guess i will be playing this weekend. I guess the bomber was setup more for rock racing then crawling. I hope to go brushless, just not a good time for it now.

Thanks All for your input.

[rngrchad]

Originally Posted by k0Re7

So it sounds like i either need to get a 550 21t titan or get a 10 tooth pinion gear and stay with a 540 motor. i guess i will be playing this weekend. I guess the bomber was setup more for rock racing then crawling. I hope to go brushless, just not a good time for it now.

Thanks All for your input.

Man, fwiw, I flog and I mean flog on my completely stock 35t 12/64 and my motor and esc rarely rarely ever get more than warm! I just can't see you swapping motors and it be fine.....somethings going on. Are you running in tall grass all the time?

[JohnRobHolmes]

I also carry 550 motors now, in varying price points from sealed can to hand wound.

[k0Re7]

Originally Posted by JohnRobHolmes

I also carry 550 motors now, in varying price points from sealed can to hand wound.

After i get this working "normal" i plan on getting a nice brushed motor or brushless system from Holmes Hobby. If this crap does not fix itself it may happen sooner then later.

[k0Re7]

Originally Posted by 84yoda

Get the 550 can 21t titan. Stock gearing. 3s.

I got a 550 Titan 21T motor insalled tonight. i will see how it works out in the morning. So far on the bench it does not even get warm.

[TacoCrawler]

did you already check for driveline resistance ?
everything rolls freely ?

I only mention because you added beeftubes to the axles
and on occasion the securing screws holding the Chub(s)/Lockout(s)
can be just a hair too long and touch the axle housing's drive axle shafts creating drag.

Check your soldered connections and ensure they aren't poorly soldered.
^ ESC, motor, battery, plugs etc.

The opinion's for gearing lower seems good advice.

I run a HH 35T on 3s in my Wraith... just warm to the touch all 4400mah.

good luck figuring it out

[k0Re7]

It would roll fine. I installed the titan 550 21 turn and after talking to the lhs they said the ECS was bad(smelled). SO i got a new one. It was a dynomite brushed ESC. Well i was able to run along time on one 3S and the motor did not go up in smoke. It is way to fast to crawl with it, but it fun trailing.

[rngrchad]

Originally Posted by k0Re7

It would roll fine. I installed the titan 550 21 turn and after talking to the lhs they said the ECS was bad(smelled). SO i got a new one. It was a dynomite brushed ESC. Well i was able to run along time on one 3S and the motor did not go up in smoke. It is way to fast to crawl with it, but it fun trailing.

I had a sneaky suspicion it was a bad ESC. Glad you got up and running with a proper replacement. Now, go run it like you stole it and don't fear of burning up motors anymore.

[JohnRobHolmes]

I hate to break it to you, but bad brushed ESCs don't burn out motors. The only failure modes that pass power are full throttle and shorted battery. Your esc probably smelled funny from the motor smoke rubbing on it.

[altd896]

Originally Posted by k0Re7

It is way to fast to crawl with it, but it fun trailing.

If you didn't already, that 10T pinion would be a good option to slow it down, increase torque & improve low end control to get it's crawling better.

[BroncoAZ]

I swapped in the Titan 21T motor a couple weeks ago, it works great in my bomber with lower gearing. I ran mine for about 6 hours this weekend on a camping trip (ran three 3s 5000mah packs, run time on one pack where I just beat it hard constantly was 1 hour 40 minutes, other packs were well over 2 hours) with most of that being crawling on steep granite. I do have UD gearing and a two speed trans, so it isn't a direct comparison to stock, but the motor never got hot. I will likely go sensored brushless at some point, but until then this combo is great.

I did a fair amount of crawling in hi gear this weekend. My high gear is the optional higher ratio in the Axial 2 speed trans. Hi gear just worked better on some surfaces, low gear would just let the tire grind against the rock, but high gear at a similar speed helped it hook up. Almost like the lack of torque kept it from breaking free.

[rngrchad]

Originally Posted by JohnRobHolmes

I hate to break it to you, but bad brushed ESCs don't burn out motors. The only failure modes that pass power are full throttle and shorted battery. Your esc probably smelled funny from the motor smoke rubbing on it.

Can an ESC go bad, and over volt a motor causing failure? Not debating just trying to learn here.....

[k0Re7]

I was wondering the same thing. When my motor was smoked i hooked up volt meter. it showed more volts with a little trigger pull then full pull. example= 3S LiPo Forward Full trigger pull was 12.60 | Forward just enough to start register was 12.91 volts.

[HahnsB2]

Originally Posted by k0Re7

I was wondering the same thing. When my motor was smoked i hooked up volt meter. it showed more volts with a little trigger pull then full pull. example= 3S LiPo Forward Full trigger pull was 12.60 | Forward just enough to start register was 12.91 volts.

ESCs control motor speed by PWM, therefore I believe your meter will show battery voltage at any throttle, a little less voltage at full throttle from the current draw.

[powder4breakfast]

Like the OP, I went through a few motors. The original motor lasted quite some time before burning up. During it's life, the vehicle was getting built and going through many modifications that may have had an affect. I want to eventually run a brushless system; but, now is not the time so I just threw in another cheap stock motor since the first had lasted long enough. Keep in mind I am only slow crawling with this.

The second motor was installed and I checked temps with a thermal gun every 5 mins or so while doing slow technical crawling. First day out was good usually staying in the 80 and 90 degree area. A few times the temp got around 105 - 115 degrees and I would take a super quick break and the temp would drop fast. Next day (second run on new motor) I didn't take the gun since everything seemed okay. Motor went up in white smoke after about an hour.

Mods: weight through SSD Rock Racer Wheels, bigger tires - Flat Iron XL's, VP Stage one kit, SS links and Beef Tubes. Other mods have been made; but, I don't think shocks, sway bar and other items would have an affect on weight or resistance.

I pulled the drive shafts apart to check for wheel rotation since I have Beef Tubes in the axles. Wheels seemed to roll fine... not awesome like a skateboard wheel with good bearings, but a few rotations before stopping. I am new to all of this; but, I'm pretty sure I'm not too tight with the gear mesh. I made sure that there was wiggle room... moving the spur(?) gear slightly back and forth with enough room that the pinion didn't move.

I'm pretty sure that the damage is being done when I am on a steep technical move where I have to hold the throttle a bit to keep the rig from slipping backwards while I wiggle the wheels to adjust the placement or slide into a spot... or rock back and forth on a steep technical move to get the wheels to come around or adjust vehicle placement. I would imagine this would be similar to binding the wheels since the throttle is receiving a bit of juice while not actually moving forward. I cannot see this as being an avoidable situation since technical crawling involves moves like this and other cars are running the same lines as me.

Question 1: Would a brushless set-up (Roc412 / MMP) handle the above scenario better?

My third motor has not been run yet; but, I have a Tekin Heavy Duty Crawler 35T motor installed and I dropped down to a 10T pinion. I hope the better motor and different pinion will run longer and cooler.

Question 2: How do I know if I have too much wheel resistance. If I grab a stock Bomber and lift it up, there is resistance when I rotate the wheels. There is definitely more resistance when I rotate the wheels on mine. When installing the third motor, I used a piece of paper to set gear mesh like many say to do.

So, how much resistance is too much? If I can determine I have too much, I'll look further for the cause. If not, I'll assume the new motor and pinion will fix.

Thanks for input and let me know if I need to add any info.

[84yoda]

That is one of the many reasons I, and most people go brushless. Yes it's expensive but look at what you already spent and also the down time and your time fixing an never ending cycle (unless you dish out a few hundreds on a badass brushed setup, but you still wont have the wheel speed, efficiency, motors lasting, and of course pure awesomeness of brushless).

Yes, MMP/roc 412 will handle anything you throw at it. Bound up? It will laugh at you and pull out of it. But if your not setup with heavy duty parts, you will just break stuff doing that. It has power on tap to do crazy stuff. You will not be disappointed going brushless.

[DowntownScience]

Originally Posted by powder4breakfast

Like the OP, I went through a few motors. The original motor lasted quite some time before burning up. During it's life, the vehicle was getting built and going through many modifications that may have had an affect. I want to eventually run a brushless system; but, now is not the time so I just threw in another cheap stock motor since the first had lasted long enough. Keep in mind I am only slow crawling with this.

The second motor was installed and I checked temps with a thermal gun every 5 mins or so while doing slow technical crawling. First day out was good usually staying in the 80 and 90 degree area. A few times the temp got around 105 - 115 degrees and I would take a super quick break and the temp would drop fast. Next day (second run on new motor) I didn't take the gun since everything seemed okay. Motor went up in white smoke after about an hour.

Mods: weight through SSD Rock Racer Wheels, bigger tires - Flat Iron XL's, VP Stage one kit, SS links and Beef Tubes. Other mods have been made; but, I don't think shocks, sway bar and other items would have an affect on weight or resistance.

I pulled the drive shafts apart to check for wheel rotation since I have Beef Tubes in the axles. Wheels seemed to roll fine... not awesome like a skateboard wheel with good bearings, but a few rotations before stopping. I am new to all of this; but, I'm pretty sure I'm not too tight with the gear mesh. I made sure that there was wiggle room... moving the spur(?) gear slightly back and forth with enough room that the pinion didn't move.

I'm pretty sure that the damage is being done when I am on a steep technical move where I have to hold the throttle a bit to keep the rig from slipping backwards while I wiggle the wheels to adjust the placement or slide into a spot... or rock back and forth on a steep technical move to get the wheels to come around or adjust vehicle placement. I would imagine this would be similar to binding the wheels since the throttle is receiving a bit of juice while not actually moving forward. I cannot see this as being an avoidable situation since technical crawling involves moves like this and other cars are running the same lines as me.

Question 1: Would a brushless set-up (Roc412 / MMP) handle the above scenario better?

My third motor has not been run yet; but, I have a Tekin Heavy Duty Crawler 35T motor installed and I dropped down to a 10T pinion. I hope the better motor and different pinion will run longer and cooler.

Question 2: How do I know if I have too much wheel resistance. If I grab a stock Bomber and lift it up, there is resistance when I rotate the wheels. There is definitely more resistance when I rotate the wheels on mine. When installing the third motor, I used a piece of paper to set gear mesh like many say to do.

So, how much resistance is too much? If I can determine I have too much, I'll look further for the cause. If not, I'll assume the new motor and pinion will fix.

Thanks for input and let me know if I need to add any info.

How is your drag brake set? It's purpose is to do the same thing you speak of when crawling and holding throttle to stay put. Not sure how this changes things but will surely make it easier for you. I've never smoked a brushed or brushless motor when crawling and don't think that brushed vs. brushless is your problem here. Two days of crawling and the motor was done?

What esc and battery are you using?

Sent from my SM-N910V using Tapatalk

[powder4breakfast]

Drag break hasn't been adjusted... set-up however it comes stock. Seems to be fine and works as expected on steeps when moving down a hill. What I am talking about is straight up moves where you are on the verge of tipping over and/or flipping backwards if you make a wrong move or hit it wrong.

Esc is stock. Battery is Onyx 11.1v 4000mAh 3s.

[DowntownScience]

Originally Posted by powder4breakfast

Drag break hasn't been adjusted... set-up however it comes stock. Seems to be fine and works as expected on steeps when moving down a hill. What I am talking about is straight up moves where you are on the verge of tipping over and/or flipping backwards if you make a wrong move or hit it wrong.

Esc is stock. Battery is Onyx 11.1v 4000mAh 3s.

I'm finding through my reading that the stock esc on 3s is the common denominator!

Do you have any 2s that you could try to see if the motor lasts a bit longer?

Sent from my SM-N910V using Tapatalk

[powder4breakfast]

The only 2s batteries that I have are the bullet plug type. I have not tried to connect them with my fat little sausage fingers once in the Bomber tray... not sure if it's possible.

I did finally run the new Tekin Heavy Duty Crawler motor and the 10T pinion set-up tonight. Temps stayed cool in the neighborhood of upper 80*. Hopefully the better motor and 10T pinion do the trick and hold me over for a while. It would be best if I could hold off on brushless for as long as I can. That being said, the real test will be my next visit to St. George on the obstacles and terrain that fried my last two motors. Fingers crossed.

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Edit - 07/05/16

Update: I have since run my Bomber in St. George with the new Tekin motor and 10T pinion. Outside temps were in the upper 90*'s. I checked the motor temps often over almost 2 hours of slow crawling and every few minutes when playing on steep technical obstacles. Motor temps only broke 100* a few times. I'm sure the better motor helped; but, I imagine the 10T pinion played a bigger role. If things remain in check like this, I will be very pleased with the swap to a 10T pinion and will be able to wait some time before the jump to brushless.