Point motor and lights power source

[Red Fox]

I'm trying to wire up my control panel to get my point motors, signals and other layout lighting working. I'm not too sure on the power source I require (my layout is DCC so doesn't have a DC controller). My signals and lights are 12v DC, my point motors are standard Seep PM-1 solenoid types. Do I need a power source that can provide both DC and AC power? I'm really looking for an easily obtainable all in one solution that won't cost me an arm and a leg, any recommendations?

[Miss Prism]

Do I need a power source that can provide both DC and AC power?

No. You need a 12V d.c. source. If you google around, you will find one that is suitable for your current requirement, which could be quite high depending on how many lights and signals you have. (Try Maplin.) A secondhand PC power supply will also be a cheap way of getting what you want, especially if you could convert your LEDs from 12V to 5V working (PC power supplies have many amps available on the 5V outputs.)

[Red Fox]

The panel I'm constructing will control 11 points, 10 of which will work in pairs, 6 four aspect signals, 4 route indicators and 2 shunt signals (all LED's and 12v). Would 1amp be enough? Would either of these two be suitable?

 

 

http://www.maplin.co.uk/Module.aspx?ModuleNo=227631

http://www.maplin.co.uk/Module.aspx?ModuleNo=48908

[noiseboy72]

Don't use a PC power supply unless you know what you are doing ! They are designed to supply PCs with known power loads. Connecting a light load such as a few point motors and signals may cause voltage instability issues.

 

For the point motors a Capacitor Discharge Unit (CDU) will give much more reliable points operation and reduce the power supply capacity.

 

I would go for 12V 3A PSU. This will give fast recharge to the CDU and plenty of power for the signals and mimic panel. I would fit a pair of fuses, one for the points (3A) and one for the signals (1A). This will help to prevent damage to the PSU from faults in the system

 

If you are DCC, why not consider making the signal and points control DCC as well ? Join MERG and the kits are very cheap and easy to build. About £60 - £80 to control the amount of signals & points etc. you are talking about.

 

And yes, either of those PSUs should be fine. I would go for the 3A one as detailed above.

[Miss Prism]

I think a single Seep PM1 might take up to 1.5A peak, so a pair operating in parallel could drain 3A, leaving no headroom for your lights, which might be up to a constant 1A (say). So unless driving your points via a CDU, I think a 3A source might not be quite enough. Suggest think in terms of 5A if not wanting to add in a CDU, e.g. http://www.maplin.co.uk/Module.aspx?ModuleNo=42702

[noiseboy72]

A CDU is the way to go as it will eliminate the flicker of the LEDs every time you throw a switch. in this case, a 3A PSU will be fine.

 

The peak current on a 3A PSU is somewhere closer to 6A for the pulse duration needed to throw the seep motor, so a 3A will be fine, just a bit flickery for the signals. A big capacitor across the signal feed decoupled by a diode to the main bus would also work, but I would go with a CDU all the same.

[Red Fox]

Thanks for you help guys. There is a CDU in the circuit so I will probably go for the 3amp unit.

[Suzie]

The 3A unit should be fine if you have a CDU. I would recommend that you might like to use a higher voltage than 12V since the typical 12V auxilliary output from a DC controller will be not smooth and nearer 18V in a lot of cases and you might find that things do not behave as expected when given a regulated supply instead - typically expect to see about a quarter of the oomph in your point motors! Using a CDU will reduce your current requirement considerably because without it you would be looking at at least an 8A supply to run a pair of solenoids at the same time without making the lights flicker.