Cutting a motor commutator & motor tweaks

[EeePee]

Nothing comparable in that box I sent ya? I wonder what number Fantom is similar to the 766!!!

I looked, and wondered the same thing, then said eff it, 767s on both sides. Which bring me to a question... asked below.

PM me and I will cut you a deal on a ton of them......same with the 729 version.

I just wanted one, to try for less comm wear. Don't really need a ton. :mrgreen:

The question I have regards spring tension. I went retarded reading old posts about 19 turn motors and brush and spring set ups, over informed myself. I kept coming away with more tension on the positive, less on the neg. Nothing we all haven't heard before. I broke out my 'Tedrockz Box Of Springs And Brushes' and Fiddle Stick'd a few and put 7.0 on the positive, and 6.5 on the negative. Purple and red, tweaked a tiny bit to get exact numbers. So the question is, in general, are the crawler guys over springing the motors? And if so, is it for no reason other than improved drag brake performance? Cause my Losi does that in the axles, so I'm thinking, lighten up on the springs a little bit and save my comms. Users of other trucks could increase the drag brake in the controller a little and lighten up in the spring department and save those comms all the same. Or, is there an actual torque increase with these super stiff springs?

 

[JohnRobHolmes]

I would think that we are over springing them on the negative side at least, but until we have controllers that can on-throttle drag I think it is an evil that is tolerable for better control.

 

[EeePee]

Well, my Losi is pretty much on the drag brake the entire time! Hah! :lmao:

 

[EddieO]

It was pretty common on all stock/19t motors to run decreased tension on the negative side......in modified, we always used equal tension on both, very rarely did we run less on the negative....

And as I have told you before, stiffer springs give you more RPM, softer more torque. Pretty much any dyno shows this.....

And anyone who wants to argue it, I can probably get every major motor builder from the last ten years to say the same thing.....Jim Dieter, Oscar Jansen, Darryl Silva, Eric Anderson, John Tag, Chad Phillips, Todd Putnam, will all tell you the same thing.


Here is an excellant thread, where multiple tuners chimed in, as well as multiple other dyno users......the other side was the guys that claim it felt different, or read in on a website trying to sell stuff....

http://www.rctech.net/forum/electric-road/97952-motor-tuning-questions-4.html

Why companies put stupid statements on their websites on springs is beyond me....

Later EddieO

 

[EeePee]

I read all that twice. I would say we're closer to stock or 19t motors than mods, so that ideology would apply to our motors more so than the mod motor approach would. No?

When is soft too soft? We're not on the gas nearly as long or constantly to see or feel brush bounce (I think?). Are there telltale signs on the comm of this?

 

[EddieO]

Brush bounce can be nasty on start up too.....often thats the bounce were concerned about...

Rough edges on the comm slot can be a sign of brush bounce...

As for what's too soft, well, there is no answer on that....

I can tell you, Red/Green combo was the softest we would run in Touring Car....but that was with the older motors......as battery voltage went up, we started going stiffer and stiffer.....up to the point of running purple/purple. Voltage plays a big part in spring tension too. In 1/12th scale, which ran 4 cell NIMH, we would run super soft springs because there was little brush bounce, as it decreased the rolling resistance on the cars....blue/blue or green/green wasn't uncommon.

All you can do is test.....

Later EddieO

 

[EeePee]

Didn't think of voltage, but I did consider rpms. And we use more voltage than all those on road yada yadas... :mrgreen:

We need someone to dyno some 35 turns with different springs! And brushes!

 

[EddieO]

If ever get time......maybe I will get to do a multiple motor show down....though I'll probably get a warning for vendor bashing when I post the results

Later EddieO

 

[EGRESSor]

Or, is there an actual torque increase with these super stiff springs?

it feels so

i really like the P94 brushes w. 9 or 10mm comms and red or purple springs for the front and black for the rear motor

You'll notice parts of the serration aren't as worn as other parts, so at this point I'm not done with the break in yet. Also notice the mess in the endbell. Brushes are typically made for 7.5 mil comms so when breaking them in on a ~10 mil comm, you really take away some material before they're fully seated.

just round or bevel the edges of the brush face a little , itmakes the break in faster and lowers the comm wear

 

[JohnRobHolmes]

If ever get time......maybe I will get to do a multiple motor show down....though I'll probably get a warning for vendor bashing when I post the results

Later EddieO

That is the price you pay for being a vendor, you can only show data on other vendors products and have to keep your attitude and interpretations under control. You wouldn't get warnings for being an ass anyway, you would get infractions "thumbsup".


Dyno away, information is always good. Whether you can present the information without bashing is your choice.

 

[EeePee]

it feels so

Christian!!! Don't you have a dyno? I don't want "it feels so", I want numbers. :mrgreen:

Jeff Gill! Rockcrawler! Don't you have a dyno? Lemme borrow that sucker. Put the shipping cost on Tedrockz's tab. :mrgreen:

Let's do something and show some numbers. Ya know, mod motors, 19 turns, stock motors, cool. Great. But that's not what we're using. Let's test out the 35 turns. All the way from stock Integy motors, to tweaked versions, to all the handwoundeds out there. And how about brushless equivalents. Oh yeah!

 

[JohnRobHolmes]

What about some other brushed motors? I have some special ones that are equivalent to 540 and 550s, but technically not near the same as the motors we have been talking about for the past 32 pages. And then some Cobalt Pullers too.


Anybody have a brake dyno or universal dyno we can loan? Inertial dynos are great for tuning, but they really don't give the full picture of motor comparisons.

 

[EeePee]

Sure! Whatever! But how about a target kV rating? Of course, as close to a 35 turn as we can get. Because besides me owning a small collection of various 35 turns, they seem to be a very (if not thee most) popular wind. No?

 

[JohnRobHolmes]

Eh, it is a toss up between 45t and 35t. Shooting for a similar KV (and what about timing advances?) and voltage will be a great starting point. Small differences in construction will make the Kv and Kt change with each particular build type, but at least we can have a baseline. When we get there, new thread time.

 

[EddieO]

I have 7 turbodynos....2 fantom, 3 robitronics, 2 Lavco, 1 GM, 2 CS, a couple weird ones I found.....

The Turbodyno is really the only one that actually measures torque.....the rest just kinda guess. I am not a fan of the fantom, as it only tests at 5 volts, which can easily hide a bad motor, plus its easy to trick it bad results because it doesn't really measure the torque.....I know some people have used it successfully. The robi is much better flywheel dyno....test at much higher voltage.

I am in the process of modifying a turbodyno 45 to be pretty trick, but I have had little time to work on it with all the orders...

I sent magtrol 20k in 2005 to make me a dyno......they had my money for a year, and sent it back saying they could not produce a dyno for our motors that would work........

Later EddieO

 

[JohnRobHolmes]

I have some designs for a universal dyno and just need to code up the DAQ chip to play nice via USB or serial. It is rubbish that they couldn't make you a dyno, they really aren't too complicated.

 

[EeePee]

Well, sticking with a commercially available dyno makes the most sense to me, that way anyone can play along because they too can buy it, or possibly already have it.

http://www.competitionelectronics.com/pages/turbodyno.html

BRUSH & SPRING EFFECTS on RPM, AMPS, TORQUE, OUTPUT WATTS and EFFICIENCY are readily seen due to the extreme repeatability and sensitivity of the TURBOdyno.

We can get pretty nerdy in here.

 

[TEDROCKZ]

Jeff Gill! Rockcrawler! Don't you have a dyno? Lemme borrow that sucker. Put the shipping cost on Tedrockz's tab. :mrgreen:

You just ain't know!!!.

Lots of talk of new stuff!!! Pics or it's all lies:mrgreen:

 

[EeePee]

I just ain't know? Pffff. You just ain't know grammar!

I think I just remembered you got his dyno! Do work son!

 

[TEDROCKZ]

I think I just remembered you got his dyno!

No! Fleabayed one and it went kaput...off to CE with it