|View single post by Steve Soar|
|Posted: Thu Apr 8th, 2021 10:06 am||
Back to super-capacitors.
There seems to be two basic types, one of which is the EDLC,
this has symmetrical electrodes and construction, so although marked + & -
I wondered if they can be used in a bipolar circuit.
So I have connected 3 off 0.47F 5V capacitors in series,
and mounted them on a running loco chassis (see photo).
Polarity is correct when running forwards, but is reversed when running in reverse.
This appears to work well on my dirty tracks, and will run down to a much lower speed,
with the capacitors connected than without capacitors.
Forwards or reverse is ok,
but I don't know if running in reverse will eventually damage the capacitors.
I have run this in reverse for over 1 hour with no problems.
When running at higher speed (10V) and supply is switched off,
then loco continues to run for approximately 1 metre forwards or reverse.
Running on my uncleaned tracks is much improved especially at creep speed.
The super-capacitors were bought off ebay 0.47F 5V
I will continue to run for longer periods.
Now completed 4 hours running in reverse, all working well,
still giving 1 metre run when supply switched off (from a 10V rail voltage).
I have also tested capacitors on a power supply,
and they appear to work well with reversed voltage.
Not seen any degradation .... yet!
Testing to date has been with a linear DC controller.
I have just tested with a PWM controller,
and as expected this needed a small ferrite-inductor in one of the rail supplies.
All looking very promising, I have not cleaned this track in months,
but loco is now running very well, even at very low speed (a big improvement).
There is a problem with emergency stops from high speed,
the super-capacitors run the loco for over 1.5 metres before stopping.
So if a quick stop is required, then it could be done by shorting out the rails... !!
(after switching off the supply)