MTH AIU: Control Powered Switch Machines with AIU
(Aristocraft, LGB, USA Trains etc)
To control a 2 wire G scale switch machine (like Aristocraft or LGB) with the MTH AIU requires a couple of extra components to get working. The AIU is designed to control 3 wire switch machines as is used in O and HO gauge.
Control 2 wire powered switch machine with AC power and diodes: (Aristocraft, LGB)
To control a switch with AC power you will need two rectifier diodes and an AC power supply. (AC power supply can be from 12-18v and will want it to be between 1 to 2 amps.)
(I have AC power supplies and diodes available for purchase if you need them.)
See this diagram on how to wire:
Here is a photo the setup on an Aristocraft switch machine: (Note I have red jumper wires from each IN port to simplify wiring for additional switches)
Diodes will look like this:
The two white wires are from the AC power supply. One wire goes to one side of the Aristocraft switch motor and the other goes to "IN" slot(s) on the AIU port. It does not matter which of the two wires is connected to the AIU and switch motor.
Next you will need to solder one end of two rectifier diodes together with the other ends facing the same direction for insertion into the AIU. (Solder the diodes in opposite directions, one with the white line on the diode closest to you and the other being furthest away. Then solder the now common soldered end of the diodes to a single wire and run that to the other side of the switch motor as shown.
Ensure the power supply is plugged in and you now have the switch machine ready to go.
Lastly, you will then need to use your DCS remote to add that switch port as a selectable switch. Once added you can then use the straight and switched buttons to control the switch.
To simplify the install of several switch machines, you can also do the following:
- Run one wire from the AC power supply to the first AIU "IN" port and then run jumper wires from the first "IN" port to the second "IN". I then repeated this for the number of switch machines I planned to add.
- Next run the other wire from the AC power supply directly outside and then split it out from there to run to one side of each of the switch machines that you plan to power. (This will save you from having to run a dedicated power wire from inside the house to each switch machine.)
- Next run a wire from each pair of diodes outside to the designated switch machines.
- To simply swapping out AIUs or moving the AIU, you can use a multi pin connector as shown below.