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Atlas Switch Machines
Craig has a question on Atlas switch machines:
“Can I use the track bus to power the switch machine or should I use a separate power source? I model HO scale.”
SUBMIT YOUR QUESTION
The track power is DC. For the switch machines should be powered from an AC supply (typically 12 volts AC). The reason is that if you use DC, over a period of time, the armature in there will become permanently magnetized and will not move anymore. Also, make sure to use momentary switches that will return to center OFF position when you take your finger away. They are not meant to be powered on continuously.
I use small toggle switches (Atlas is too big and bulky.. make poor contact). They have the function as:
MomentaryON-OFF-MomentaryON.
A seperate power supply for switches, unless you are using DCC and a stationary decoder. Some brands require a separate power input, but some brands work of the track power.
For analog (conventional dc) a seperate power source is recommended otherwise you will see a dip in loco performance every time you throw a switch/turnout
For DCC, everything can be powered from the track bus.
For DC, the track bus voltage varies according to the controller speed setting.
Many DC controllers have separate output terminals for powering accessories such as turnouts, which will need their own switches.
(On model layouts, it is best to call track switches turnouts, to avoid confusion with electrical switches.)
I recommend you get a book on basic railroad modelling, it will answer most of your questions, and many that you haven’t even thought of yet.
I am running DCC at 13.7 volts for my bus, but in order to use my Bachmann snap relays, I have to increase the voltage to 16 volts.
Some electrical devices will work quite happily at slightly below their rated voltage. I don’t know the Bachmann relays, but they may work ok with what you have. It is safe to experiment with this.