Model Railway Forum

I take your point completely and even though the capacitors I use have specific + & - terminals, surprisingly they do help to improve the performance of my locos that have them.

The only reason that 16v capacitor blew up that I can think of was that the tender motor needed a major service but I didn't do that part, it is more than likely that the explosion would not have happened had I serviced the motor before connecting the capacitor to it but having said that, the tender motor was probably in need of some parts replacement aswell.

brian1951 wrote: ↑Mon Jan 15, 2024 5:10 pm I have never needed stay alive in any of my locos.

That is probably because you may well have all nice new locos with nice new pickups on all wheels.. and not many older ones. I have some smaller new 0-6-0 locos which do not falter on dead frogs because they have much better pick ups rather than the older models. You probably don't have any dead frogs either.

RogerB wrote: ↑Mon Jan 15, 2024 2:47 pm I looked up a diagram for you. Does this help? R-

Thank you Roger

I have found that the 220u 35V capacitors do make a difference on pure DC. I fitted thin strips of insulating tape over one side of the track spaced at exactly the wheel spacing on a Triang Jinty. At low speed, the loco would halt; at the same speed with the capacitor, it would manage to cross the tape. However, my main layout has low frequency (c 150Hz) PWM and the capacitor negatively impacts the slow running by changing the waveform from square to sawtooth. As an experiment, I charged the capacitor from the track and then touched it to the loco wheels, there is a very slight movement but seems that is all that is needed to reduce chances of a halt due to momentary absence of track contact. It may well be that high PWM frequencies (which most are I believe) will be OK and benefit; I do not have the immediate capability to test that.

Hello viscount. yes I have had good results with couple of locos. The ones I have been using are 30 volt. I have fitted one to a old Hornby A4 which halted at a crossover now it goes over it well.

Glad it is working for you. As I said, my PWM which provides great low speed performance, doesn't like them. Where I can, I fit extra pickups to help (in tenders mainly). I did a short YouTube on that; see @OOelectronics if interested.

Interesting thread this. Even as a kid I always wondered whether a capacitor could somehow be integrated into a model engine. Just a second or so of power would be enough to stop most stalls.

Might give this a go.

Great! Let us all know how you get on with that. Good luck.