6 replies to this topic

[Phil Smith]

The inside lane of the hairpins are a bit tricky with the 45 Ohm controllers I currently have wired up. 90 Ohm is actually too slow but perfect for the grand kids since keeping the cars in the slot is the main goal. My problem is I only have one 90 Ohm controller.

 

I was wondering if I could cut the lowest band and add a resistor to slow the response. I know that's less than ideal but it beats buying three 90 Ohm resistors. Any thoughts?

 

[Ramcatlarry]

You could get a 60 ohm resistor and change them out, or get some older Professor Motor diode HO controllers and just control the voltage instead of the amps that all resistor controllers do.

[Dave Crevie]

Or you can find some of the old style wire-wound POTs and clip them on the power side of the controller. Assuming these are not transistor

controllers. That will give you variable top speed. 

[Phil Smith]

You could get a 60 ohm resistor and change them out, or get some older Professor Motor diode HO controllers and just control the voltage instead of the amps that all resistor controllers do.

 

I was trying to avoid buying new resistors. I've already spent more than I had hoped on pickup shoes (I found a bag after ordering almost $40 worth) motor brushes and silicone tires. And I need to buy more parts even though I have whole box box full of T-Jet stuff. You never have the right parts, do you. Or at least I never do.

 

All for something the grand kids might be tired of in a month.

 

Or you can find some of the old style wire-wound POTs and clip them on the power side of the controller. Assuming these are not transistor

controllers. That will give you variable top speed. 

 

I have a variable power supply, so I can reduce the voltage which I've already done.

 

And after giving it more thought,  adding a resistor at the beginning of the resistor windings will do nothing. It seems you need to add a resistor between the last resistor winding and the full power band. And that's going to create a huge leap in power at the end of the power curve.

 

So I guess I have to spend some more @#$%^&* money and buy some 90 Ohm resistors!
 

[Ramcatlarry]

https://www.ebay.com...roller&_sacat=0

[Phil Smith]

Thanks, Larry. I went with replacement resistors from Mid America. I got 4 so I'd have a backup in case the grand kids managed to fry one.

 

It seems that reducing the resistor value might be more doable than increasing it. Eliminating the switch and using a variable rheostat instead of the fixed value resistor? What do ya'll think of this?

 

https://oldweirdhera...aining-control/

 

[Phil Smith]

I did an experiment today. I have some 100 Ohm variable rheostats that I used for HO controller brake pots. I hooked one up to a 45 ohm controller like the 10 Ohm in the diagram above and checked it with a volt ohm meter.

 

With the pot turned up to 100 Ohms, the resulting ohms was 31, just as the calculator below predicted. The taper is no longer linear. It's closer to a log taper. At half throttle it's at about 30%, so it's not quite as bad as the chart.

 

https://www.allabout...nce-calculator/

 

With the 90 Ohm controllers I'm using with my track, 200 Ohm pots will give me 62 Ohms. And I can dial in lower Ohms.

 

Not idea and I'm not going to sell my Difalco, but good enough for my grand kids if they stay interested long enough to race some 440x2's, which I have box full of.