Cutting a motor commutator & motor tweaks

[jdobb]

have you played with brush cutting? you can really adjust the torque and power to where you want it.

[Charlie-III]

I say I see no calibration info, where is your standard....can you trace to NIST??!!




Sorry, based on other comments, I just had to (leaving myself open to getting slammed.......sigh.....).

Motor looks decent.

As I stated before, I need to do some back to back tests on my dyno (numbers won't match anything else.....) to see some crawler motor differences.

[EeePee]

Originally Posted by Charlie-III

Motor looks decent.

How's this one look?

[Cordwood]

Originally Posted by EeePee

How's this one look?

RPM's on that look like 35 turn territory. If that's a 35 turn, it's a bit more stout than any 35t I have.

[EeePee]

It's labeled as a 35 turn.

[EddieO]

Are those torque steps?

Later EddieO

[EeePee]

Do they not look like TQ steps? 6, 8, 10, 12, 14, 15.9

[EeePee]

So, how many people are trying to beat that number right now?



I repeated it three times and I can compare it to another motor. I can make a video to prove it, I guess.

[Cordwood]

Originally Posted by EeePee

So, how many people are trying to beat that number right now?



I repeated it three times and I can compare it to another motor. I can make a video to prove it, I guess.

The more I look at it, I'm not sure there is anything to beat. Look at the amp draw. It has to pull 23.6 amps to make 15.9 oz-in of torque. If my best motor could pull 23.6 amps without the torque sensor limiting it, it would make 13X watts and much more than 15.9 oz-in torque.

Dyno the similar motors in amp steps, but make the last amp step 21. Then compare.

[EeePee]

Okay, but I have to do this dang work thang first. So in about nine hours I will.

[EddieO]

Heh, watching you guys struggle over this oddity is fun...

Some dumb questions to make you think.

Watts is RPM x Torque...right?

If Torque is preset.....and RPM isn't....what happens if motor A makes more RPM than motor B, but motor B makes more torque?

Later EddieO

[EeePee]

Originally Posted by Cordwood

Dyno the similar motors in amp steps, but make the last amp step 21. Then compare.

Alrighty. My beater Fantom on the left and the other motor is on the right. I cut the one slip just to line them up.

[EeePee]

Originally Posted by EddieO

what happens if motor A makes more RPM than motor B, but motor B makes more torque?

Add a tooth or five to the pinion gear on motor B and call it a Reedy.

[Cordwood]

So there you have it. The difference is clearer in amp steps. Compared to motor X, the beater Fantom shows to be a superior motor in torque and efficiency with similar power in the bottom range of amp draw. Motor X pobably doesn't ever make as much torque as the fantom but power takes off in the upper amp range.

Both being 35 turn, you'd have to disclose specific armature characteristics to explain why the difference.

[EeePee]

Spring testing with the beater Fantom after a comm skim. I've confirmed I have the Lemans brushes in it. They leave a pretty color on the comm.

I Fiddlestick'd and swapped around tens of thousands of springs til I got fairly solid consistent numbers and hit it on the dyno.

The left was more or less black springs, the middle two were a mix of purple, red and green, and the rightmost one is with gold springs. All were handpicked and Fiddlesticked. Great tool. Unlike the iPod Touch's camera. Terrible tool.

[EddieO]

Heh, notice how RPM goes up with the stiffer spring and torque goes down?....Told ya

Later EddieO

[Cordwood]

Nice data. X2 on the spring tension since he beat me to it.

On the amp steps, I threw that 21 for step 6 out earlier because it was less than where motor X makes 15.9 and about where the "other" motor we discussed makes 15.9. Doesn't apply to the fantom since it hits 15.9 around 20 amps. So, dont do that...

[Cordwood]

Go try it with the 4 FS springs on 4s, I dare ya. Report back with pics...

[JohnRobHolmes]

Originally Posted by Cordwood

Go try it with the 4 FS springs on 4s, I dare ya. Report back with pics...

Yeah, give it a shot and tell us how that works out for your comm

[EeePee]

If I knew someplace to get replacement parts I would, but I don't, so I won't.