>Having done a few ready made examples I want to do now an own design - lets
>name it "model railway regulator".
>
>>From my further experience with analogue circuits I know that pulse width
>modulation will help to fight detent torque of model engines, on the other
>hand with increasing iron loss the temperature of the engine will increase.
>So I want to try a combination of DC with PWM.

DCC decoders use something in the region of 500Hz for most cored motors to
have a frequency that is high enough to have a PWM signal that can produce a
good average voltage, without being that high that the losses in the core
become a problem.

However do be aware that more can type motors with coreless armatures are
being used (Faulhaber, etc), and these require a frequency of the order of
20kHz. The reason for this is that the low frequency used for cored motors
is low enough to mechanically vibrate the windings to a point where they
physically shake apart. using 20kHz is above the mechanical resonant
frequency of the armature winding, so the mechanical does not occur.

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