I have had some feedback re the controller problems re the brake pots burning out.
Although I had cleaned the controllers a week or so before the problem it appears that the wiper pad may get contaminated with a conductive compound .
This can cause the voltage from the power side of the wiper pad to be contacted to the brake terminal.
Thus current flowing where it should not be.
I had been cleaning the wiper pad with Shellite on a cotton bud. Then I put a very small dot of the grease - the process recommended by Professor motor.
Ok so maybe something got on the wiper to cause the conduction. This may not even be visible as some lubricants can also conduct current.
So I suggest we cover all reach controllers with a plastic bag when not in use .
I strongly suggest that if you have a Professor Motor Controller it may be a good idea to service it before EACH race meeting .
Also purchase the correct grease as recommended by Professor Motor. This is called Super Lube and is in a grey tube available from Thunderbird Slot racing.
Thanks to those that sent the information in reply to my email. I am happy to say though the controller performs well with the Pots as used by Diffalco.
Of course the controllers still have to be serviced as above
So be warned that servicing alone may not solve the problem . Best t keep checking the controller is nit heating up in the front top corner ( that’s 50mm away from the pots )
If the controller is hot it is best to disconnect & try a service before more damage is done. It is not a good idea to leave the PM controller connected to the track when not in use .
Peter D. Has sent this info he found on Professor Motor website. I am not sure if this information is included in the controller directions as its a while since I red the directions .
Hi John , Found this on the Professor motor Site
Use & Care Instructions
Caution ! : Regular maintenance is required
to keep the controller contacts clean and free from foreign objects & debris.
Failure to properly clean, lube and maintain the contacts will
cause the controller to fail, will allow the car to be driven
without the throttle being depressed and can result in the wire wound pot used for brake control becoming short
circuited & damaged. Please take this warning seriously
and follow this process to keep the contacts clean & properly lubricated :
Hope this helps. Peter D.
Also Chris in Melbourne was kind enough to give this explanation
The fact that the cars move slowly tells me a bit more, I don't have a professor
motor circuit diagram but the way tracks are normally wired up this tells
me that there is a stray positive somewhere on the trigger or the trigger
wire which would make the cars move and heat up the brake pots when at rest.
It is not the full track voltage so that is why it takes a while for the
brake pot to heat up, the type of pots normally used in this application
are usually rated in milliamps and not normally rated for 12 volts which
is not usually a problem in the brake circuit, the Difalco pot must be a
I hope this has been an education in controllers for us . So hopefully with the maintenance recommended the Professor Motor controllers will continue to operate correctly
Another thing to watch out for with the Professor Motor controllers below:
CONTROLLER PROBLEMS .
For a while some people have been having problems with the Blue track controller being intermittent . I took it apart to service it yesterday.
I checked the wiper contact and all the usual service points.
I then notice a bit of a “knoble “ on one of the track connection wires. This was where the wire entered the controller. So in stretching the wire I could see it looking as if the center conductor was broken . On further stretching the insulation broke as the copper core had already broken . So here in was cause of intermittent power I thought. The insulation was holding the inner core together - sometimes.
I examination I found the other two wires to the track plug were the same . I could not believe the controller was still working - most of the time.
The wire used in this controller was the one with blue silicon insulation . The core wire is fairly fine in gauge compared to auto 4 mm cable.
So something else to inspect on your controller . I have has some of the plastic insulated wire brake in the same position.