9V motor modified with capicators for dead spots

[relhak]

I help run a public display that includes a 9v train loop that runs 2-7 hours per day, 365 days/year. We beat our motors and track to death. The curves tend to get a lot of plastic dust dumped on the track, which eventually creates dead spots until they get cleaned (sometimes just once a month). I'm looking for a way to smooth out the current to go over the dead spots (and reduced any start-stop wear). We have a timer to keep the train from running constantly, so it can't be a battery recharging from the track. I was thinking that adding a capacitor could keep the motor running for a half second (or more) until it hits a fully powered area again. Maybe around a .5 - 1 farad supercapacitor, added via the power tap connector on the top.

This will probably take a polarized cap that would be destroyed if the motor is reversed. But we only run in one direction, and can leave a sign to not reverse. Or just add a diode to the track power. But if there's a cheap way to switch the polarity, it would be good safeguard.

I took physics 102 20 years ago, but never really put it to use. So I'm sure there are more knowledgeable people here that could point out any flaws in my idea. Any input, or links to someone who has done this before?

Stuart

[Heppeng]

You could try using a Relco electronic track cleaner - needs a 16V AC supply to work.

[Zerobricks]

Like you said dont reverse polarity, maybe use a diode just in case...

[Dutchiedoughnut]

I'd suggest picking up power from more points on the train. If this is build into the motor itself, you could hide a train motor in the rear most carriage. This also saves you if you manage to stop the train completely on a dead point, a capacitor won't really save you there. You can also modify one of the carriages to clean the track for you.

Here is the sort of carriage I have for my h0 track:

Edit: You can use two capacitors (one forward and one reverse) and select them using diodes. It's a bit more complicated than just using a capacitor though... did you try getting the biggest non-polarized capacitor?

Edited August 30, 2014 by Dutchiedoughnut

[JopieK]

Non-polarized elco's seem to exist in quite a large range: 0.47 – 2,200 μF e.g. this one: http://nl.farnell.co...-rad/dp/1236693

I did not experiment with them, but that would be very interesting to do!