# matching arms to magnets



## wyatt641 (Jan 14, 2012)

okay guys..my question..i disassembled and cleaned a original chassis.i bought some 3 ohm arms a couple years back from t-jet griggs.i used one of these arms with some dash blue and white magnets.the chassis runs like bat out of hell but gets hot quick..are the magnets too strong??should i use some old original magnets?? i am using a stock power supply..is that the problem?? tips please..just toying around here.


----------



## Boosted-Z71 (Nov 26, 2007)

3 ohm arm is really hot for a stock power supply, due to the fact you more than likely do not have enough amps from your power supply. It will run somewhat cooler on more amps but a wind of that ohm is going to produce some heat regardless. As for the magnets, it will likely produce more heat with stronger magnets. I assume this is a drag racing arm, so maybe lessen the traction magnets if you have them on the chassis.

Jim winds some killer arms, look for anything that you can to reduce friction, you could also try to reduce the brush tension a little to help with the heat, but most of the time large amp draw, low winds like a fair amount of brush tension, which also acts like friction on the arm as well. 

Boosted


----------



## Boosted-Z71 (Nov 26, 2007)

Also the wall wart power supplies that come in the sets are awful for the output which is to be DC current to have large amounts of AC current which also makes the cars run hotter. 
So running these on the wall warts you have several things working against you. 

You can find a clean DC output power supply from a laptop that will give you 3-4 amps at 18-20 volts that would do a much better job at powering your track. One per lane would be great, I find these all the time at the local Goodwill store, generally they are $1.99 or so. 

Boosted


----------



## alpink (Aug 22, 2010)

wyatt, unless you specified other than ....
those arms are intended for drag racing and only being run for about 10 seconds at a time.
what are you using them for?


----------



## wyatt641 (Jan 14, 2012)

alpink said:


> wyatt, unless you specified other than ....
> those arms are intended for drag racing and only being run for about 10 seconds at a time.
> what are you using them for?


sorry i forgot to add that al
yes the chassis will be used for just drag racing..these were drag arms he was letting go of for really, really cheap a couple years ago,he had quite a few from non payees and he had a FIRE sale i remember.i got them and never really did anything with them until now..sooo. until the kids baseball season starts i decided to toy around.


----------



## LDThomas (Nov 30, 1999)

wyatt641 said:


> okay guys..my question..i disassembled and cleaned a original chassis.i bought some 3 ohm arms a couple years back from t-jet griggs.i used one of these arms with some dash blue and white magnets.the chassis runs like bat out of hell but gets hot quick..are the magnets too strong??should i use some old original magnets?? i am using a stock power supply..is that the problem?? tips please..just toying around here.




Dash blue and white magnets are too weak to road race an arm of that low resistance. Drop in a set of Dash polymer magnets and the heat will be reduced. But by that time, the weakness of the power supply will be quite apparent. You won't be able to come anywhere close to getting full performance out of that car.


----------



## Bill Hall (Jan 6, 2007)

*I smell bacon!*

Sorry Wyatt!

Under 6 ohms the duty cycle takes a pretty good hit. Thats why you dont see them as factory equipment and you have to rely on specialists or go home grown to procure them. They are a potential complaint/warranty/lawsuit waiting to happen by the uninitiated. 

They are a blast and rest/cool proposition. 

If you road raced a 3 ohm and lapped it around some, it should burn your thumb when you pick it up. Obviously one would like limit that kind of exposure ie: prolonged, deep, hot.

Was it a first or second degree burn?


----------



## wyatt641 (Jan 14, 2012)

Bill Hall said:


> Sorry Wyatt!
> 
> Under 6 ohms the duty cycle takes a pretty good hit. Thats why you dont see them as factory equipment and you have to rely on specialists or go home grown to procure them. They are a potential complaint/warranty/lawsuit waiting to happen by the uninitiated.
> 
> ...


1st degree..felt just a bit o heat and got out of there in time..lol:wave:


----------



## Rich Dumas (Sep 3, 2008)

The are 3 ohm armatures that can be run on road courses without overheating. There are different combinations of wire gauge and the number of turns that can get you the same ohm value. You might take a look at the DC HO Motors site for info on armatures for drag and road course applications. Unless you are an expert on winding armatures it is best to contact the supplier and tell him what you are trying to do.


----------



## alpink (Aug 22, 2010)

wyatt, all the suggestion I read here are spot on.
when drag racing real low ohm arms in outlaw type inline cars folks use compressed air, like keyboard cleaner, cans upside down to "freeze" the arm prior to the pass.
this helps keep the arm from getting too hot (they still get quite hot though) and allows better conductivity for the brief period that they are super cold.
using this technique on pancake cars is a bit more difficult with the limited access to the armature.


----------



## Dushkwoneshe (Apr 27, 2012)

alpink said:


> wyatt, all the suggestion I read here are spot on.
> when drag racing real low ohm arms in outlaw type inline cars folks use compressed air, like keyboard cleaner, cans upside down to *"freeze"* the arm prior to the pass.
> this helps keep the arm from getting too hot (they still get quite hot though) and allows better conductivity for the brief period that they are super cold.
> using this technique on pancake cars is a bit more difficult with the limited access to the armature.


That's *cool*, alpink... My buddy, Rick, and I would put our Tyco F1's
in the freezer for bit before racing (road course)... For the 1st few laps,
they were screamers...

John
.


----------



## slotking (May 27, 2008)

> The are 3 ohm armatures that can be run on road courses without overheating


.

Yeah, I ran 3ohm arms for years with both super II mags and poly mags with very little issues on our road courses


----------



## wyatt641 (Jan 14, 2012)

Rich Dumas said:


> The are 3 ohm armatures that can be run on road courses without overheating. There are different combinations of wire gauge and the number of turns that can get you the same ohm value. You might take a look at the DC HO Motors site for info on armatures for drag and road course applications. Unless you are an expert on winding armatures it is best to contact the supplier and tell him what you are trying to do.


i got them from tjetgriggs whom i was told was ill at this time..since i have not seen him on for a while i inquired in a thread a couple weeks or so ago.


----------

