except I’m using two 2200u caps instead of 1000u. While this CDU works fine most of the time, there are occasions when it has to throw two turnouts at the same time, and just sometimes it doesn’t have enough “oomph” to do it.
How can I add a little more “oomph”? Could the problem be with the power supply I’m using? It’s just the AC outlet of an old Arnold controller. Or does the CDU more or less do away with any deficiencies in the PS? i.e. once the caps are charged, that’s that - a bad PS is just going to take more time to charge the caps? What about even bigger caps? Do I run any risk of motor burnout?
Many thanks in advance!
Nee
PS For those who read my post “Hot dang! That’s a lot of wiring” I hope to post a picture of the completed control panel. It’s a thing of beauty… from the outside!
Once the caps charge, the source power supply doesn’t really matter. If it recovers reasonably fast, your supply is fine. What size wire do you have leading from the control switch to the dual motors? If the wire is too small you will loose most of your power due to excessive resistence in the wire. A heavier wire might help here. You could go larger on the caps, but the recovery time will go up. Two 4700’s might be too much. It won’t burn out the switch motors though. Try the heavier wire first. Or run a second pair of the same size wire you already have, in parallel with the first set. That gives an effective increase in wire size without cutting it down and running new wire.
Thanks Randy. That’s interesting and I’ll look into it. Meanwhile I hooked up my DCC controller’s 18VAC power supply to the CDU just to test it out and it’s much improved, not only in recharge time but also “oomph”. I guess I’ll invest in a new power supply.
Just make sure the capacitors are robust enough for the 18 volts. If the circuit was designed for a 12 volt input, they might very well be 16V capacitors. Over-volt large electrolytic capacitors and they can literally explode. If that’s an 18V AC power supply being rectified into the circuit, even a 25 volt capacitor might not be big enough. Go 50 for safety here.
Don’t go much higher than about 18 volts. I bought a Snapper CDU awhile back and hooked it to 24 volts and started getting what I called “point bounce.” The points would make contact with the stock rail and bounce back. I reduced the voltage to 12 volts and the point bounce was cured but the throw still sounded rather anemic. I am looking for about an 18 volt power supply which should be about right.
If your CDU can take an AC input source, try the AC terminals of an old power pack. They are usually 16 volts, that should work good. The last time I used solenoid switch motors was an N scale layout with Atlas switches a long time ago. That’s when I built a CDU, mainly to prevent the rather delicate Atlas machines from burning out. I ran it off the AC terminals of the old cheapy power pack that came with my first N scale set, while my Tech II actually powered the trains.