Droping the motor Votlage form 12V to 9V

[zcr2244]

I have an older L gauge DC set that runs at 9V that I'm concerting to DCC with the Hornby DCC system that runs at 12V. I was wondering how to limit the voltage going to the motor so that I don't burn it out. I have experimenting with voltage regulators

and they work but they are a little bit big. Has any one else tried doing this?

PS I don't want to have to set the max running voltage with the DCC transformer as I just want to limit the power with extra components, in between the orange and gray

inputs that direct power to the motor.

[Rog RJ]

You could try fitting a series of diodes (wired in inverse parallel to allow forward and reverse running) in series with the motor feeds. Each diode would drop about 0.5 volts each and the power dissipated is shared between the diodes.

Inverse parallel
Orange

wire ____>>>>>>____ To motor terminal
Orange wire ____ and < represents a diode
The diodes could be inserted into either the orange or grey wires or even into both

[Rog RJ]

Oh dear, my little diagram failed to load properly but I think you probably know what I mean.

[Blackbird]

The DC output to the motor is controller by the DCC decoder. Although most motors are nominally 12V the DC output from the decoder is variable, 0-15v (approx). Most nominal 12v motors will run at around 15v max. The decoder can be programmed for maximum

volts output (speed). So you can program decoder to give maximum to suit your loco's motor.
CV5 will set the Max volts, 255 being max, then 190 will give (approx) 11.5v max, which should be suitable for your (nominal 9v) motor, or you can reduce CV setting

to suit.