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· Registered
1 Posts
Discussion Starter · #1 ·
Hi everyone,

I have a H&M cu1 model controller, that has had the original wiring replaced.

Please could anyone help me by explaining which wires are solely for the output, and which wires form the mains input supply?

I look forward to hearing from you.

Kind regards

· In depth idiot
8,790 Posts

Firstly, this is a control unit for 12V DC supply only.
Significant hazard if a mains voltage connection is attempted!

Secondly welcome!
To repeat, this is a control unit for a 12V DC input only.

As originally wired there will have been three wire colours: two wires the same colour, these are the inputs, and two wires in differing colours which are the outputs to the track.

To make this unit work you need a 12V DC supply: it was intended to be powered from the auxiliary 12V DC supply found on many of the H&M controllers, which contain a mains transformer, rectifier and low voltage track supply controller. This control unit, often referred to as a 'Slave', only contains the low voltage track supply controller.


· Registered
489 Posts
DO NOT CONNECT TO THE MAINS. This controller is intended for a 12vDC input.

Just an additional note. If running it as a slave from another controller that has an additional 12v output, one will need to know if the "Master" controller 12v fixed additional output is on a separate transformer winding to its normal controllers 0-12v output.

A totally separate 12v DC transformer ideally of around an amp or an amp and a half will be ideal as H&M slave controllers do have overload protection built in. One can therefore in theory run them from batteries if required but NEVER directly from the mains.
The type of controller designed to be a master controller for these would be something like the H&M Powermaster which has its 12v DC fixed output on a separate winding and also pushed out additional power (Think it is 2 1/2 amps) so it has plenty in reserve to do so.
Beware of controllers like the H&M Duette which have its 12v DC fixed output shared with the "B" side of the controller. One can use this 12v but it is designed for things like turntables or for using a slave controller where the track will not touch and come into contact with the normal controllers track that is being controlled.
H&M used to sell Powerpack cased transformers specifically for powering their slave controllers. While one version was around 2 amps, another version designed to power more than one slave was pushing out 6 amps if I recall correctly which today is equivalent to some of the larger DCC systems outputs.

You do not need a H&M branded cased transformer. As long as it pushes out 12vDC and has around an amp it should be fine. (Others will be able to say more about this as my knowledge is limited).
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