Hello everyone.
Hope you have a good weekend.
A recent interesting discussions about controllers has inspired me to look again at this issue.
In the good old days :-) better slow running could be achieved by using half wave rectification or pulse power as it was described by H&M in their Clipper and Safety Minor controllers. This basically switched out one half of the bridge rectifier and fed this to the track. The resulting signal was still dc but was very chopped and at mains frequency of 50Hz. Full wave of course was and is 100 Hz (if I understand correctly)
This was fine for old open frame motors but even these would heat up, of course it would be a total no, no for our modern motors.
When I first tried a feedback controller I was very pleased with the way things ran, but very very unhappy with the noise and heat generated.
I then acquired my Orbit Supertroller which is still in use to this day. As a back up and spare I re-worked my H&M Safety Minor and fitted it with a proper bridge rectifier and modern circuit protection.
I have been using a Kent Panel Control hand held feedback controller on my test track, this has switchable feedback levels. The lower being for new motor types. I also modified this unit by increasing the feedback resistor so reducing the over all feedback levels. Like this the controller still gives much better running performance even set to the low feedback setting. Most motors do not like the full feedback setting and will slow down considerably.
Despite my modification I still note that some motors get hotter than I would like even our good old Lima ones! Today I acquired a Gaugemaster hand Held controller (non feedback) and have been using this. Another point to note is that using a feedback controller will hide locos that have mechanisms that need servicing! Our Smokey Joe (Hornby 0-4-0 HP motor) now springs into action instead of making a nice steady slow start! This is the same for one of my Wrenns.
So my questions is this:
Is it the feedback effect that causes the motors to run hotter or is it the wave form from these controllers? A pure dc controller will have virtually a pure dc output with very little ripple, if it is there I would expect it to be a nice smooth sign wave. But with feedback control you are going to get a very spiky or saw tooth wave. However, research seems to suggest that some ripple at a higher frequency is beneficial to getting the best performance from your motors. (Cooler Controller from the USA) Is it possible to have a smoother feedback?
I would be very interested to hear your thoughts.