Professor Motor Question

[smithspeedway]

I just got 2 Professor Motor controllers. Turns out they are "PMTR2062 Carrera Home Set". They have three wires. I hooked them up as our regular Parmas do. The cars have great brakes, but don't move until wide open throttle. The sheet that came with them said to reverse the wires at the power supply to correct this. It did make the cars have smooth acceleration from low throttle up, but now the brakes don't work. Advice?

Steve

[chappy]

Steve , give Oliver a call right at PM , he is great at explaining this stuff.
Knows them inside out.
Bob

[waaytoomuchintothis]

He ought to, he's the tech who fixes them! LOL. Seriously, Oliver has been very kind to me and very helpful.

[RichD]

Electronic controllers sold for use with home set 1/32nd tracks are wired for negative polarity, apparantly your track is wired for positive polarity. If you only use resistor based controllers polarity is not an issue, but most electronic controllers can only work with one polarity. When PM sold diode based controllers there were a few dual polarity models and you could install a dual polarity kit in a controller that did not have that feature. The newer PM controllers use transistors and dual polarity is not an option.
As you found the controllers that you have will work if the brake wire is left disconnected and the black and white connections are exchanged. If you don't need brakes you can just live with that, otherwise you have two options. You could swap your controllers for positive polarity ones, or you could change the polarity of your track by reversing the wires that go to the power supply and also reversing the wires that go to the rails. If you switch your track to negative polarity visitors might not be able to use their own electronic controllers. The latest Difalco controllers are dual polarity.
One of these days I will have to write an article titled "Controllers for Dummies" or better yet "Everything You wanted to Know About Controllers, But Were Afraid To Ask".

[smithspeedway]

Thanks. It has fortunately been 6 years since I had to wire a track, so I'm rusty. No one else is using electronic controllers. If I swap the taps at the power source, do I have to do anything different to the brake circuit?

[chappy]

If you follow Rich's instructions above Steve, you need to swap the power at the power supply, and then the wires to the lanes have to be swapped otherwise it will run backwards.
How many lanes are you talking about ?
Bob

[smithspeedway]

6 lanes. I did the swap. The PM controller doesn't seem to have the brakes that our Parma's do.

[chappy]

The only controllers I have found wih great brakes are the old fly pro, with the capacitor built in.
My PMs are Positive , with adjustable brakes and sensitivity.
They work pretty good.
My difalco also has adjustable brakes and sensitivity that work great.
The Controllers you have are for Carrera home set, so you may find that if you are not using the right voltage , same as Carrera, you may not get all the benefits of the controller.
Bob

[sixtiesracer]

Why don't you get in touch with Slot Car Corner.They can more than likely solve your problem on the first visit.

[RichD]

Here is what the circuits look like for both wiring schemes:
This is how home sets are wired.


This is how most 1/32nd club tracks and 1/24th commercial raceways are wired.


The brake connection does not have to be changed if you change polarity.
A PM controller should have the same brakes as a Parma controller, the exception to that would be some of the older diode controllers that had a fixed resistor in the brake circuit. If the braking does not seem to be up to par you should take a resistance reading across the black and red controller connections, the reading should be very close to zero. If there is any resistance there is likely to be a poor connection someplace.