Thinking about dyno's for brushed motors

[R6cowboy]

I ordered one as well. It took a while but the tracking did finally update. Says that it has been sitting in Atlanta for the last few days.

I hate it when my packages go through Atlanta or Boca Raton, damn things take forever.

Just checked again. The one I ordered on Feb. 18th still says it's been sitting in Walnut, CA since Feb. 22nd.

On a good note, the replacement unit I ordered on the amazon shows it arrived at my local post office this morning, along with some kester 44 solder, wick and flux.

[Frankentruck]

I ordered one as well. It took a while but the tracking did finally update. Says that it has been sitting in Atlanta for the last few days.

I hate it when my packages go through Atlanta or Boca Raton, damn things take forever.

Just checked again. The one I ordered on Feb. 18th still says it's been sitting in Walnut, CA since Feb. 22nd.

On a good note, the replacement unit I ordered on the amazon shows it arrived at my local post office this morning, along with some kester 44 solder, wick and flux.

I've been having similar delay issues with stuff shipped to me using USPS in mid to late Feb. However one package that eventually showed up transformed it's contents from a Black Magic motor into a Cam motor.

[coxbros1]

Man.....too bad it didnt transform into a Le Mans motor

[Frankentruck]

Man.....too bad it didnt transform into a Le Mans motor

It's been a long time since I owned a LeMons motor. I have been eyeing a couple with aluminum endbells.

Have any of the people with this rpm dyno setup experimented with comparing worn and good brushes to see the difference?

[juicedcoupe]

Have any of the people with this rpm dyno setup experimented with comparing worn and good brushes to see the difference?

Probably too many variables.

Are the brushes the same? Springs?

Was the motor freshened or just changed the brushes? Did it need to be freshened up? (Comm condition?)

Were the brushes just worn down or have they been damaged or overheated?


I can't speak for everyone, but I rarely just change brushes. At the absolute least, I'm going to flush it out with contact or motor cleaner, oil the bearings/bushings, clean the comm, and check the brush hoods. If it needs more, I'll go farther into it.

Often, I will touch up a motor before the brushes need to be replaced. I'll clean the comm, touch up the brushes in a cutter, blow out the motor, and oil it.

IMHO, brushes are too cheap to run them so long that risk damaging the comm. I just bought new Tekin brush and spring sets for $8 each.

[Frankentruck]

My experience has been that motors used for off-road driving need cleaning, lube, etc many many times prior to needing brush replacement. However I've been out of RCs for many years, and now that I've caught the bug for it again, this dyno intrigues me as to what motor conditions are perceptible. I've been eyeing a Tekin 900 fun setup, but this seems like a lot of fun as a home development project.

[juicedcoupe]

All other things being equal, I suspect that a set of worn (shorter) brushes would have a similar effect as running lighter springs. But that would be be taking about a set of otherwise perfect brushes, just shorter.

[juicedcoupe]

I ordered one as well. It took a while but the tracking did finally update. Says that it has been sitting in Atlanta for the last few days.

I hate it when my packages go through Atlanta or Boca Raton, damn things take forever.

I just checked, it's in Orlando now. They have sent it from California to Tennessee, Georgia, and now Florida. I live in Mississippi !!!

[Frankentruck]

IMHO, brushes are too cheap to run them so long that risk damaging the comm. I just bought new Tekin brush and spring sets for $8 each.

I just picked up a couple of used Tekin motors to use for parts (I wanted the brush screw heatsinks). The brushes are oriented low/wide in the Tekin hoods, and most of my motors have the brushes narrow/tall. So far I'm seeing Reedy Radon brushes as my primary option for pre-contoured brushes.

[juicedcoupe]

IMHO, brushes are too cheap to run them so long that risk damaging the comm. I just bought new Tekin brush and spring sets for $8 each.

I just picked up a couple of used Tekin motors to use for parts (I wanted the brush screw heatsinks). The brushes are oriented low/wide in the Tekin hoods, and most of my motors have the brushes narrow/tall. So far I'm seeing Reedy Radon brushes as my primary option for pre-contoured brushes.

They make both, laydown and upright.

The HD motors use upright brushes. The upright brush and spring kit is #TT3804, I have a pack in front of me.

Shop around, prices vary.

In addition to Reedy and Tekin, Jconcepts, Team Brood, Holmes, Integy, and others still offer them.

[juicedcoupe]

Finally got my rig up and running, sorta. My power supply did not like the inrush current demand of the 15T Trinity, so I grabbed a 6 cell pack that still had a little juice in it.

I made a mounting plate from 1/8" lexan and put 3M pads on it, stays perfectly still.

When I wired the speed control, I add a set small wires on the motor side with banana plugs. They plug directly into my DVM, keeping me from having to fumble with test leads.



The motor I tried out was a Trinity Titanite, 15X2. It is Factory rated at 33,700 rpm, at whatever voltage and timing they chose.

This motor is in the "as is" condition when I removed it from one of my trucks. While still in good condition, it could use a quick once over.

I grabbed a pack that wasn't topped off, so I only had 7.1 volts (and it was fading). At 0° timing, it ran 29,600 rpm and pulled 5.3 amps. When I get a chance, I'll try a fresh 7 cell pack so that I can trim it back.

[Dadio]

That's a tidy setup , I need to do something similar with my V meter wires .

[Coelacanth]

Nice setup, JC. Has anybody tested a brushed motor on a fully-charged 2S LiPo that hit 35k RPM yet? Of my 5 motors I've tested thus far, only 2 broke 30k: the Le Mans 240SB @ 30,457 rpm and my surprising Le Mans 480S @ 33,446 rpm. I rebuilt that one long ago and it probably has some other comm under the hood than the original...maybe a 240SB comm.

I have a Trinity D3 that almost broke 30k, coming in @ 29,753 rpm. I have a bunch of other brushed motors but they all need rebuilding first. No time for that right now...

[coxbros1]

If u get a chance pull that arm out of the 480s and look and see if its a single or double wind....the 240sb is a double and the 480s is a single

[juicedcoupe]

Has anybody tested a brushed motor on a fully-charged 2S LiPo that hit 35k RPM yet? Of my 5 motors I've tested thus far, only 2 broke 30k:

Here you go.

Kyosho 12X2 Mega. The comm and brushes aren't fresh but they were cleaned with a comm stick. Timing at 4°.

7.2 volts- 39,820 rpm.

7.4 volts- 43,161 rpm.

I tried to spin it all the way up on a fresh 8.4 pack (~10 volts) but the tachometer couldn't get a reading.