# Smalltime



## Hornet (Dec 1, 2005)

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## smalltime (Jun 3, 2006)

Hornet said:


> Tim,how's your knowledge of small needle/roller bearings.
> What do you think of their electrical current carrying ability.
> What i'm sorta kicking around is trying a roller/needle bearing as a controller wiper,instead of a wiper pad,on my cheap Difalco.
> It's more a curiousity test to see if anything can be gained by rollerizing the wiper pad,and i figure on using a Difalco,that way,i'm only out a trigger if it doesn't work.:thumbsup:
> ...


I actually built a device for work about ten years ago that ran direct current thru a ball bearing. The bearing was an open side variety, but probably much bigger than your application. Aprox 1.5" dia, and probably 3/16 dia balls.

But this carried ALOT of juice. It was a turner for a ram EDM machine, if you know what that is. It machines thru spark erosion, kind of like welding in reverse. Anyhoo, this thing handled about thiry five amps, at variouse voltages for hours on end, and NEVER even blinked.

I would try to get some dielectric grease to it though. The above application did run with a dielectric fluid. You might want to test it somehow with an ohmeter.

Let us know how it worked.


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## Hornet (Dec 1, 2005)

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## alpink (Aug 22, 2010)

the only thing I can say is, if it were worth doing it would have been by now. the various after market slot car controller manufacturers are always looking for an edge for their product to out sell the competition and many high tech individuals customize these highly developed slot car controllers themselves. if someone isn't already using such a "wiper", then it is not practical. just my opinion. your mileage may vary.


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## Hornet (Dec 1, 2005)

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## Bubba 123 (Sep 10, 2010)

Hornet said:


> A roller bearing or something mighty close by the looks of the pic's is in use now.
> Figured on not spending a 100 bucks though to find out it's not a great improvement
> 
> http://www.sabatona.com/ultra-glide-upgrades.html


hi,
a said, the resistence of current, conductivity, volt age, amprage....
will b a constant variable due to the movement & non-mechanically conection
(like soldered or carbon brushes w/ spring tension...)
also, the bearings w/ eventually get "Burn-Marks" on surfaces.. (like old points in 1:1 distributers..) which will add to friction of the bearings....
the lubrication in the bearings also reduces the electrical conductivity as well... and adds to the "Resistance" of currant, voltage & amprage...
the clossest thing that U r trying 2 achive, is the properties & mechanics
of an "A/C" motor (alternating curent 2 the mag fields instead of the armature
IE; Brushless/no brushes on commutator......

OK, my spelling rotts.... & just got up.. (NO Coffee or cigs yet :freak

but this is the basic idea :thumbsup:

hope this helps..:wave:

Bubba 123


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## Hornet (Dec 1, 2005)

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## 440s-4ever (Feb 23, 2010)

Even if it has some resistance it's no big deal, after all the controller is all about resistance, right? If WOT resistance is a problem you just need double contacts at WOT so it hits posts on both sides of the + / - equation.


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## smalltime (Jun 3, 2006)

440s-4ever said:


> Even if it has some resistance it's no big deal, after all the controller is all about resistance, right? If WOT resistance is a problem you just need double contacts at WOT so it hits posts on both sides of the + / - equation.


Your right,
who cares if there's resistance. I'm sure a defalco has a microswitch for WO

The only thing I'm curious about is the "repeatablity" of the thing. Or, Does it do the same thing on every pull. If it's different, then your toast.


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## Dslot (Sep 2, 2007)

Hornet said:


> ... a roller/needle bearing as a controller wiper,instead of a wiper pad,on my cheap Difalco.


"cheap Difalco" ?


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## Hornet (Dec 1, 2005)

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## Dslot (Sep 2, 2007)

Did you notice on the Sabatona website you linked to, that there's a parts page? 

*SABP110 Turbo Trigger Ball Bearing Upgrade kit $15.00 *

Don't know if that means ball-bearing trigger-pivot or ball-bearing wiper on the other end. If it's the wiper, for 15 bucks, you might be able just to clip it off and use it in your, er ... cheapie.

-- D


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## Hornet (Dec 1, 2005)

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## Slott V (Feb 3, 2005)

My old Lionel train uses something like this on the third rail-


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## Hornet (Dec 1, 2005)

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## Slott V (Feb 3, 2005)

This sounded like what you were thinking of. That one is probably larger than you'd need but it seems to use the same principle. Older Lionel trains are heavy and draw a fair amount of amperage through these rollers or 'collectors' as the train guys call them. The one shown is a floater type for a light in a car but the pick-ups for the engines (below) have more precision lever type action (sounds like what you want to do) and a nice spring tension:










They do get hot after a while. And over time the roller gets a build up on it that has to be cleaned off. Probably from the rail getting dirty being at floor level. Designing a smaller version of this in a hand held controller wouldn't seem to get as dirty would it? I only set mine up at Christmas but the hobby train guys probably know how to get the most out of this set up. I'll bet there are aftermarket set ups out there. Your design would obviously need the roller situated 90° of this kind.

The roller rides on the arc of a rail. I wonder if it would work the same if it rolled on a flat circuit board? The wiper on a controller usually contacts two connections for a brief moment whereas a roller wouldn't. Could be good or bad.


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## Hornet (Dec 1, 2005)

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## co_zee (Mar 28, 2005)

At one time, Len, and I believe a brother of his also were into 1/24th racing out east. He is also well known in the RC Helo world, especially in competitions. He now owns Advantage Hobby. I have used one of his controllers and they are super smooth. The smoothest I have ever used.


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## Hornet (Dec 1, 2005)

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## Brixmix (Dec 2, 2007)

I know he has one on his difalco also. He makes his own arm and hinge. He won't tell anyone what the bearing is or the application it comes from. Since his RC back ground I would say the RC world would be were to look


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## SDMedanic (Apr 21, 2011)

The arm is bent into an L shape to allow the bearing mounting screw to be parallel with the resistor. The bearing is mounted on the arm. It's a large non flanged bearing. Say 5/16" in dia and the same in length. 

Passing current through ball/roller bearings will eventually lead to bearing failure. While its a neat idea I am not sure you could not do as well with a Parma Turbo with a ball bearing trigger and a flemming hinge or a well polished resistor and wiper. 

Steve


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## Hornet (Dec 1, 2005)

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