Cutting a motor commutator & motor tweaks

[rock hard]

Ok,conserning p94 brushes,are the octagon brushes anygood?
And are the eclips brushes only for use in the checkpoint style hoods?

Also are the alloy style endbells worth considering
like what used to come alot of the epic modifieds?
arent most of thos p94 hoods?

Thanks

 

[rock hard]

On slotting arms

I have been slotting arms lately to get the detent torque a bit lower.

Like this?

[/QUOTE]

You are removing steel from the arm.......RPM goes up, overall power goes up. It's very similar to a 4mm arm, but the way the arm reacts to the magnets is different....the slot basically lets it glide past the magnets easier. I've tried them in 4 magnet cans.....including my own rig, while the power was beyond nutty, the drag brake isn't great. The low speed control is awesome......from testing, 2 magnet cans seem the best with them.

While you can drill balance them, it just takes MORE steel out of the arm, thus making more RPM and more power......plus balancing them isn't so easy, as your going WAY down into the armature. It took a bit, but I found the epoxy balancing putty. Everyone used to get it through LRP, but I talked to Andreas and he told me the company went out of business......so, after some searching and emails, I found a quaility replacement (might even be the same stuff, just the US company)....

When Orion won worlds with them, they did some stuff to make drill balancing very minimal....arms were cherry-picked and then wound a certain way.....if arm needed too much correction, it was tossed....

Later EddieO

 

[mik220]

this gives me some good info to start with i've been out of the hobby for a few years but i'm ready to get started again

 

[rock hard]

Reason I bring it up is i have been planing to do a 4 magnet mini
but now I'm wondering if slotting the arm is better.

I'm thinking that I would have to slot the arm before I send it off to be wound
It appears that it wouldnt be all that hard to do really,but I wonder just how easy it would be to screw up an arm?

and I read I thought that it made the motor less efficient,why is that?
it would take less to get it to spool,it would be smoother
so why would it be less efficient?

Slotting arms is old, been done since the 80s....it fell out a favor for a long time because it lowers the efficiency of the motor



Later EddieO

 

[EddieO]

The above photo is not a slotted arm. That is a bone stock trinity arm. That small groove down the center is a guide for the balancing holes, basically where the center of the segment is, so the grunts at trinity wouldn't drill off center (though thats useful for balancing)....

This is a slotted arm (yes, this is the first 2011 LE to be released in a few weeks)....

A slotted arm will ALWAYS be less efficient than a full arm with everything the same (comm size, web size, etc) because there is less steel. It's just the way our little motors work. Racers would never run the 4mm arms in Touring Modified, as a 5mm blank was good for another 40+ seconds of runtime. ......the removal of steel on the slotted arms has a lessened effect. Typically we saw run time of about 20-30 or so seconds less......without getting too technical and confusing everyone, I'll just leave it at that.

I dunno how well slotting a 380 arm would work.....there is very little steel in the first place. It might just work, I dunno.....I'll admit, my 380 experience is limited.....I would think the 4 magnets would work better for them though.

Alloy endbells are good.....the only downside of them is you have to watch for how they may get banged up on the rocks. I recommend using motors covers with them.

THe Checkpoint only has two brushes available for it......the Atlas (standard) and Infinity (high end).

A p94 is different from the octagon brushes.....The whole p94 thing was kinda a gimmick to sell more brushes. It was pretty normal for all trinity team motors to use p94 brushes, but the face of the brush was cut down to to be a regular size brush......only trinity sold p94 brushes though, so they kept you from buying brushes from anyone else....their polarized springs served the same purpose. Ernie P was a smart business man....

The Ellipse brush (not eclipse) was designed for the Cobalt 2 modified motor.....it was a good brush, very similar compound to a XXX lemans...not quite the same though. The Octagon brush was just a different shape XXX lemans brush......

Later EddieO

 

[rock hard]

I was thinking the same thing about getting banged up,but motor skids are easy enough.
I tell ya what bugs me more than banging the motor,is grease getting into the can from the face. I keep my gears well greased,and have yet to bust a gear
but a small amount of grease always seems to make its way into the can.

I think the p94 is a good fit with a 10mm comm.

I have been playing with various combos

4-5mm webs
7.5-10mm comm
standup,laydown,p94

The 2 mag can 5mm web,10mm comm with p94's has the best hold of what I have tried
so its out back.I'm not worried about brake up front so I have a 4 mag can
4mm web 10mm com with laydowns up front for the finess
I'm very happy with this combo,but my 500 mAh batteries dont like it
So I'm looking for something around 7-800

 

[Scattman]

THe Checkpoint only has two brushes available for it......the Atlas (standard) and Infinity (high end).

Later EddieO

Have any of those on hand? I would like to rebuild mine but am out of brushes. What different springs were offered for the Checkpoint cans?

I liked using the Checkpoint cans since the brushes and springs are better protected from the rocks but I have some TI cans, would those be a better option for me performance wise?

 

[EddieO]

I like the CP motors....the brushes were awesome compounds. My only gripe was the shunts don't solder so easy.....

I have about 100 or so of the teardowns left.....OEM only got the plastic endbell version, which I liked better for everything but Touring Car, as the Aluminum was better for that for the heat dissipation. For all other classes, the lighter weight plastic was superior.

There is about 4 different sets of springs, though they did release a team spring that I have a scare few pairs of......

I do have brushes in stock......I have tons $5 a pair on the Atlas and $8 on the Infinity (this is below cost!)....

Rockhard, I have a few customers that run the 2 mag rear, 4 mag front setup......I thought about offering it as a combo, but decided to wait until I could have two identical cans for it.....just looks weird to me.

Later EddieO

 

[JohnRobHolmes]

You may find that slotting the arms axially makes the startup even worse. On a 5 or 7 segment armature it reduces the detent torque. On a 3 segment armature I have found it to make the startup jumpier and increases the detent torque slightly.

 

[EddieO]

I haven't noticed that in any of my testing......their are videos of my truck from the last comp I went to......low throttle control was great and the extra power caught everyones eye.

I've tried Tri-Rotor arms, which would basically be a slotted arm off-axis...they performed similar.

Maybe post up some photos of your slotted arms, might be able to spot the differences why you experienced a more jumpy start up.

Later EddieO

 

[JohnRobHolmes]

I sent all the last ones out, so I will need to slot more for pics. I used a 1/8" endmill and took off material about 1mm or .040" deep. Maybe a wider bit would get different results. The power certainly went up a bit, but the startup speed increased as well.


It looks like your slotting removed quite a bit more material. I will try a 1/4" bit and plunge it deeper next time and see how the results change.

 

[EeePee]

This is still the bestest thread on RCC.

 

[rock hard]

Rockhard, I have a few customers that run the 2 mag rear, 4 mag front setup......I thought about offering it as a combo, but decided to wait until I could have two identical cans for it.....just looks weird to me.

Later EddieO

Its like having a brunet on one arm and a redhead on the other
I get my 2 favorite flavors,together

 

[EddieO]

I've had a blonde and brunet, does that count?

Later EddieO

 

[TEDROCKZ]

This is still the bestest thread on RCC.

Also found some new tinkerings on the bay. I for some reason have started picking up some of this older stuff. Some things not very old are vintage:lmao:
Found 12 kits to playaround with on various motors...

 

[out4crawlin]

Do you have any P-94 brush hood kits you would like to sell?

 

[killswitch]

Also found some new tinkerings on the bay. I for some reason have started picking up some of this older stuff. Some things not very old are vintage:lmao:
Found 12 kits to playaround with on various motors...

I've picked a couple of those up as well. I really needed a set of replacement hoods for one of my motors that took a nasty hit to the endbell.

 

[TEDROCKZ]

Do you have any P-94 brush hood kits you would like to sell?

There is more on E-bay. Look for Sheldons Hobbies"thumbsup"

 

[out4crawlin]

Alright, thank you.;-)

 

[out4crawlin]

Eddio, what kind of a can is this?