Does anybody have any experience with these?
That particular unit? No. But the theory is sound - it’s how all DCC decoders drive the motor. Way back when a similar thing was done using an SCR as the controlling device, but usually at the 60Hz line frequency which made them a bit buzzy. Very much like DCC decoders that don’t have ‘high frequency’ or ‘silent running’. The throttle linked uses a seperate oscillator to generate the pulse frequency and it appears to be well over 60Hz.
–Randy
Yes I have one and love it
It’s the smoothest hand throttle i’ve ever used
it’s only draw back is it will heat up a little when running 2 or more older Athearn locos
but not to the point of being uncomfortable
OLD Athearn BB engines pull an average of .75 amps each and 2X to start. THe 3 amp throttle would be a better choice. for those.
I e-mailed him last year but got no reply. One of the guys working at the LHS says that he’s no longer building these throttles, but he comes into the store occasionally. I have two SCR throttles from Intrakit (no longer in business) that I like and I also have a couple of MAW-SCALE DYNA-POWER Transistor Throttle Units (the name is written across the top of the control box, to give you an idea of how big they are [:D]) that I really like. They were made by Millholme Models, in England. In addition to an On/Off switch and a direction switch, they have a throttle handle, which moves smoothly through an arc of about 270 degrees and a brake handle of similar design, but moving through an arc of about 180 degrees, and having six distinct settings. The brake position for normal running is marked “Off”, with the next position being “Lap”, which simulates coasting. This is followed by positions “1”, “2”, and “3”, which are progressively heavier brake applications, and finally, “Emergency”. The throttle has a built in momentum feature which is always on, and the brake handle also has a momentum feature. In position “1”, braking is very gradual, becoming less so at “2” and “3”, and becoming quite abrupt (but not instantaneous) in “Emergency”. With a little practice, very prototypical operation is possible by gradually opening the throttle to the desired speed, then controlling the train solely through use of the brake. Slow speed control is excellent. My only complaint with these throttles, and it also applies to the SCR’s, is that they will not run a heavy train on a steep grade. The train will slow,an
You have discovered the drawback of PWM. At lower speeds (lower pulse widths) especially,t here is a loss of torque in the motor since power is applied for only a short time. Without some form of compensation, your locos will run very nicely at low speed but not pull as much as they could with a traditional throttle. The MRC packs have various means of load compensation, as do most DCC decoders. This helps eliminate the drawback of PWM. Head to head testing I’d say PWM can achieve a lower slow speed, but even with compensation circuitry a more traditional supply will outpull a PWM supply on the low end. It might not be a great difference with the compensation circuitry, but PWM will probably always lose.
–Randy