6 replies to this topic

[hoffmanbrent]

I'm confused by the terms positive polarity & negative polarity for controller connections on drag tracks.

Difalco drag controllers work only with positive polarity? 

Is positive polarity the most popular connection for drag tracks?

the drawing attached, is that positive polarity?

 

Thanks for the info, it will help out building our drag track

[mreibman]

There's no diagram attached.

 

Left braid on the track is negative.

Right braid on the track is positive.

 

Unlike a road course, you only use 2 pots.... 1 white goes to positive on power source. 1 black, goes to right braid (positive).

Negative on power source goes straight to left braid.

 

It's pretty straightforward to wire. I don't have a diagram of it either.

[MSwiss]

Like Mike R said, the negative goes straight to the left braid.

 

This is a bit confusing because I have a fusable link built in, and I don't have wire with a red jacket, for all the different sizes I use,  but at the control panel, you are just breaking the positive feed from the power supply.

 

What's makes it even more confusing is Difalco uses a red boot for the clip that goes to the terminal from the positive feed, on your power supply.

 

With a simple resistor drag controller, like the popular Koford, he uses a white wire and boot.

 

Hence, I painted the washer white, and colored half of it with a red magic marker.

 

With the non-relay version of the Koford drag controller, you can hook up the clips either way, and the controller will function fine.

 

With a Difalco, you need to be hooked up correctly, or the car goes without the trigger being pulled.

[hoffmanbrent]

Sorry about the attachment missing. That drawing must of been for non drag tracks, cuz it used 3 connections.
Thanks for the info, like the idea of color the one post red & white.

[MSwiss]

We drag race on Tuesday night and one of the racers was walking around earlier, with a Koford controller, with a relay on it.

I asked him what happens when he hooks it up backwards.

He answered he never has, and wasn't real anxious to try it, to find out. Lol

[mreibman]

We drag race on Tuesday night and one of the racers was walking around earlier, with a Koford controller, with a relay on it.

I asked him what happens when he hooks it up backwards.

He answered he never has, and wasn't real anxious to try it, to find out. Lol

With a koford or parma type controller it really should work exactly the same either direction.

[Jim Difalco]

Not sure why my drag controllers are so confusing. Red has always been positive on a car battery. I did it this way 30 years ago so racers would actually think about hooking up their controller versus a resistor controller that does not have a direction like a transistor model. Half red and half white on the positive stud is a nice touch.

 

Since the Koford model with a relay also uses a battery nothing should happen if hooked up backwards since it is basically a resistor controller. My drag units have a reverse diode to protect the transistor from reverse connection. Since drag tracks only have 2 connections it is hard to think of them as being positive polarity or to say that my controllers only work on positive wired tracks.

 

One piece of advice to Brent is try to keep the hook up studs to 10-32 size to make connecting the alligator clips easy to get on and off.

 

I hope this helps.