Power Central

The electric 'power plant'

The first real construction for the layout was this large electric power supply: Using a classic system of fuse -> Transformer -> rectifier -> condenser the power sources were build.

There were various voltage levels required for the layout:
· 15v DC, at least 20 amps for trains and controllers
· 12v AC, at least 8 amps for model lights
· 48v DC, at least 3 amps for the turnout drivers (I once used recycled telephone central relays for these)
· 5v DC, at least 3 amps for digital controls
· 22v DC, at least 1.5 amps for control panel LED's

Each output has its own fuse, to protect the (expensive) rectifiers and transformers from being destroyed when short-circuit occurs.
I had to actually buy only one transformer: for the 15V/20A train-power I chose a 400VA transformer, used for halogen lights (this provides 11.6V/32A AC and is not too expensive). The other components I recycled from previous projects or old electronic equipment (like some audio amplifiers). The large condensers where recycled from the same sources. Only the bridge rectifiers were bought. I never used such heavy (50v/20amps) ones before.
A lot of attention went to security: the wires I used are quite thick (e.g. the common mass output has a 1/6 inch section!). High-voltage outputs (the mains voltage and the 48v DC) were protected from accidental touching. A large metal cap was placed over the rectifiers and condenser: I wouldn't like a peace of metal, like a tool or so, to fall in between and cause damage.
This heavy power central can't be simply connected to the mains voltage: because of the large current it draws when being switched on, it could cause contacts to get burned and even the mains fuse to be destroyed. I therefore chose a large relay, controlled by a switch on the main control panel.
In November '03 a recycled computer power supply was added, so I had some extra power voltage: +12v/1,5A, -12v/1,2A, and 5v/9A I needed the +5V mainly, for various system controllers, and - as seemed later - for the turnout drivers. The 48V for the turnout drivers I used before, became obsolete...