Help! I keep burning out brushed motors on 2S and 3S!

[RC_FunLand 167]

Hi all,

 

Over the past three days, I've burnt four different Mabuchi 540SH motors- some unlabeled, some Torque Tuned. Every single time I've run a different 2S/3S battery to maybe find the issue?

Also, I must mention that these problems arise on MULTIPLE cars/ESC sets. Am I running too high of gearings? Is the "burst" or "continuous" current too strong for the motor/motor capacitors to handle?

 

Thank you in advance!

[Nicadraus 6201]

I don't think silver can and torque tuned motors can handle 3s batteries. Also what ESC are you using?

[DaveBuildsRC 210]

Batteries 100c or more?

[Ziddan 947]

I killed a torque tuned on the first drive with my Scorched dt03 (modified Aqroshot, still stock wheels and driveline) using a zeee 2s 5200mah 50c lipo and carson dragster 70a esc.

Didnt realize anything was off until it started sounding odd, losing power and i caught a whiff of overheated electronics, i think the heat caused demagnetization but i ran it around on gravel for pretty much the whole pack before noticing.

The motor still turns over when given power but it is gutless and sounds grindy/rattly.

[Jonathon Gillham 4607]

Its most likely gearing, or it could be binding in the drivetrain

If you're running the kit setup then the gearing should be fine though - have you swapped out pinions or spur? If you have then you could have ended up overgeared.

Otherwise check for siezed bearings in the hubs/shafts etc - remove the pinion and push the car, if it rolls ok then it should be fine, if it stops quickly then it probably has an issue.

High discharge batteries, high amp ESc etc don't have any impact as the motor draws what it wants/needs, power isn't pushed through to the motor

[mtbkym01 4008]

How long are you running for continuously?

[RC_FunLand 167]

1 hour ago, DaveBuildsRC said:

Batteries 100c or more?

Nah, only about 55C max.

 

2 hours ago, Nicadraus said:

I don't think silver can and torque tuned motors can handle 3s batteries. Also what ESC are you using?

So, they’re limited on 2S? I’m using a brushed AARMA ESC of some sort. Don’t know the exact specifics, will list tomorrow.

 

1 hour ago, Jonathon Gillham said:

Its most likely gearing, or it could be binding in the drivetrain

Gearing is lower than stock (stock is 23T pinion with 73T(?) spur, new is with a 17T pinion)

 

I’ve noticed an excess amount of friction, especially at low speeds. Upon checking gears, they seem to meshed half-decently.

1 hour ago, Jonathon Gillham said:

High discharge batteries, high amp ESc etc don't have any impact as the motor draws what it wants/needs, power isn't pushed through to the motor

Good to know!!

[RC_FunLand 167]

1 minute ago, mtbkym01 said:

How long are you running for continuously?

Probably 2-3 minutes with no breaks, unless I hit an obstacle of course!

[RC_FunLand 167]

1 hour ago, Ziddan said:

zeee 2s 5200mah 50c lipo

Strange, I had that EXACT battery… but it puffed and blew up after about two months of use. That’s why I no longer purchase ZEEE branded products and instead hunt eBay for Floureon (❤️) battery bargains.

[Pablo68 1049]

I did something like this with my Hornet putting a new Venom NiMh battery through a decade or older msa/resistor/silvercan set up.

After soldering the wires back onto the motor once or twice and finally smoke coming off the msc for this numpty to finally realise something was going badly wrong. I bought and esc and new motor and never looked back.

[Jonathon Gillham 4607]

2 minutes ago, RC_FunLand said:

 

Gearing is lower than stock (stock is 23T pinion with 73T(?) spur, new is with a 17T pinion)

 

I’ve noticed an excess amount of friction, especially at low speeds. Upon checking gears, they seem to meshed half-decently.

 

If gearing is lower than stock then is it the surface? Grass is harder on them than dirt or tarmac

The excess friction sounds like the culprit. Check each part, not just the gear mesh. It could be worn bearings as opposed to a siezed one, or binding in driveshafts etc. I've had all sorts of issues which range from worn parts to poor installation...

[mtbkym01 4008]

1 hour ago, RC_FunLand said:

Probably 2-3 minutes with no breaks, unless I hit an obstacle of course!

So the motor is smoking after 2-3 mins? Definitely some issue either dragging in the driveline or the surface. Back in the day our batteries only ran for around 5 mins, current Lipos and capacities see much longer run times, so components dont get to cool down. A silver can is still basically the same motor it was 30 years ago

I wouldn’t run a basic motor for anything longer than around 10 mins without letting it cool for a few mins, electric motors tend to continuously build heat, so running for longer periods pretty much will cook your motor

[markbt73 5316]

540 motors are capable of handling 3s batteries. They're industrial motors, intended to run on 12 volts, so 11.1 from a 3 cell lipo is well within the motor's specs.

But it's not meant to do it continuously under a high load. You'll want to gear way, way down, probably as low as possible with most Tamiya vehicles, make sure everything is as free-running as possible (bearings throughout, and DON'T use more than a tiny film of grease on the gears), and let everything cool down for a few minutes after every few minutes of run time.

My advice? Get a 2s battery, and focus on vehicle control and driving skill instead of all-out speed.

[alvinlwh 5895]

Gearing. I had melted a few 540 with 2S, on purpose, with insane gearing.

Also smoked one on stock gearing on tough surface. Ended up replacing that one with a 550.

[Fabia130vRS 2098]

9 hours ago, RC_FunLand said:

Hi all,

 

Over the past three days, I've burnt four different Mabuchi 540SH motors- some unlabeled, some Torque Tuned. Every single time I've run a different 2S/3S battery to maybe find the issue?

Also, I must mention that these problems arise on MULTIPLE cars/ESC sets. Am I running too high of gearings? Is the "burst" or "continuous" current too strong for the motor/motor capacitors to handle?

 

Thank you in advance!

Whats the gearing

[RC_FunLand 167]

5 hours ago, markbt73 said:

My advice? Get a 2s battery, and focus on vehicle control and driving skill instead of all-out speed.

I will admit, the car in which is the issue is taking place is the Traxxas Stampede, so I feel like the silver can doesn’t “launch” it across the yard. Probably because of some sort of internal issue, ie a bearing seized, etc..

[RC_FunLand 167]

1 hour ago, Fabia130vRS said:

Whats the gearing

17T spur and 76T pinion.

[OldSchoolRC1 984]

Assuming that's 17t pinion and 75T spur.... you've got an overall gear ratio of 12:1. 

If it's a 2wd Stampede, it won't launch across the yard as the gearing is way too tall. It's like trying to accelerate from a stop in 5th gear.

A brushed Stampede comes with 16/90 (15:1) and the VXL is 19/86. I would highly recommend gearing down to match, or at least get into the ballpark. You'll get the launch you are looking for and save some motors. 

[markbt73 5316]

Oh, yeah, that's geared way too high for a Stampede. I think mine is 15/88 or something, with the old 20 turn Stinger motor, and it could go lower.

The other trouble with the Stampede is very heavy tires. It's like trying to spin up four heavy flywheels, only two of which are powered. Smaller/lighter tires (like from a Rustler) will give you much quicker acceleration.

[Big Jon 684]

That’s way too much gear for a 540 in a Stampede! 16/90 would be my recommendation for general running, but the Arrma ESC will run a 12t 550 comfortably, which is what I’d use. Traxxas Titans are cheap, plentiful, and reliable, and shove things around nicely. The label comes off easily, too.

The Titan in my TT02 rally car pulls 27/66 gears without any issues.

[87lc2 2666]

As others said, its the gearing.  I'd probably swap a 550 in there as well, 540 is a bit small and will get hot in a Pede.  It has nothing to do with the battery or C rating.  Brushed motors can handle 3s just fine when geared properly and not run too long.  Although I have put Clods with 540s through entire packs on 3s with no issue.  Clods are pretty easy on motors gearing-wise.