Electrics and DCC - updated 22 May 2007
I had a lot of problems with voltage drop. At one point I measured a 5 volt drop around the garden, enough for a train standing on a theoretically dead section, with common return to both rails, to move. I now use lighting ring main cable as a main bus beneath the baseboards with spurs to the boards and every length of rail using bell wire. This seems to solve the problem.
After much head scratching about how to wire the layout I took the plunge and bought into ZTC Controls DCC system. Currently I have a ZTC511 Master Controller, three ZTC622 Handheld Controllers and a ZTC550 booster.
The ZTC511 and power booster live indoors. Each circuit is divided into two power districts with the breaks between the station loops and the "hidden" sidings and between the legs of the triangular junction. This limits the length of the track busses to half a circuit with two laid clockwise and two anticlockwise. All four are currently connected to the ZTC511. Separate boosters will be installed if more power is required. The indoor section as far as the triangle is a separate power district connected to the ZTC550 booster to provide automatic polarity reversal. The outside power districts can be totally disconnected when not required.
The inner track circuit and the triangle were completed in 2006. Attention is now focussed on completing the electrics and point motors for easy running of trains out, round and round and back.
I had been using a regulated DC power supply from Maplins (part no. XM21X) to power my ZTC511 without any problems. This was recommended on DCCUK as a precaution against power surges although I can't really tell if it had any effect.
Initially I installed the booster using the ZTC560 transfomer but this caused train speeds to surge when they moved from the ZTC511 powered section to the booster powered section. I guess this is because the DC power supply is rated at 13.8V which is lower than the ZTC560 at 16VAC nominal. There does not seem to be any way to reduce the voltage from the ZTC560 using the booster so I switched the ZTC560 to power the ZTC511 and used the regulated DC power supply on the booster. I use the ZTC511 default voltage setting of 14V which brings it to about the same as the booster and the problem with the surge seems to have gone away.
I guess I will use matching DC voltage regulators for any future boosters.
A word of CAUTION. The DC connections to the power terminal block on the ZTC511 are the opposite way round to those on the ZTC550. Also, I had to cut the small clips off the terminal block to fit through the case of the ZTC550.
25 August 2010
My ZT511 developed a fault earlier in the year and had to be sent away for repair. In the interim I bought a Lenz 100 set so I am now the proud owner of ZTC, Lenz and NCE PowerCab. I expect to use the Lenz for my 3mm system running with CTI control. I am back with the ZTC for my 7mm with JMRI on my PC. I am currently experimenting with WiThrottle running on an iPOD through JMRI for wireless throttles in the garden. Functionally it is fine but I am having trouble with the wifi signal strength.