commander and multipack H&M controllers

[railroadbill]

I've had an H & M Clipper controller for years, still works well. I've been given an H & M Multipack controller, which needs a 12v DC input. I've also dug out an H & M Commander controller, which I've never used, which is marked as "transistorised controller" on the front of the case. This needs a 16v ac input. (I've got transformers that supply the needed ac and dc inputs). I'd like to use them on a layout extension.

They are rather old equipment but does anyone know if the Commander and/or Multipack are non-pulse and non-feedback? I'm hoping that they will just provide a variable voltage (which I think the Clipper does and runs a rather varied collection of locos ok)

 

Thanks,

Bill

[leopardml2341]

Hello Bill,

 

The Multipack is a simple variable resisitance mat controller, in fact it works in the same way as the Clipper but without the mains transformer and the 1/2 wave switch.

 

As for the Commander, IIRC it is not a PWM or Feddback controller but just a smooth 0-12 v dc output provided by simple electronics rather than a resistance mat.

 

E & OE as usuual

 

Andy

[railroadbill]

Hello Andy,

 

Great, thanks very much for that information. Since they give similar outputs, ie just a variable voltage, I can now use all 3 controllers on the next bit of layout I'm wiring up. Reason I want to use these controllers (apart from the fact that I already have them!) is that my original plan was to try and get locos (particularly ones I'd built) running as smoothly as possible without being "propped up" by feedback etc.

 

Apart from the vintage controllers, I do have a dcc section of the layout, but that's a different story...

 

By the way, is that a Leyland Leopard coach in your pic?

 

Thanks again, very useful info.

 

Bill

[Gordon H]

Since they give similar outputs, ie just a variable voltage, I can now use all 3 controllers on the next bit of layout I'm wiring up.

Strictly speaking, controllers using a variable resistance mat don't produce a variable output voltage as such. Instead, they put a variable resistance in-line with a fixed output, and the voltage that results at the output terminals depends on both the mat setting and the resistance of the loco being driven. Essentially, the controller and the loco form a potential divider. This is why such controllers often feature a 'High/Low' resistance switch, to allow the user to match the controller to the loco characteristics.

For example, if your loco has a resistance of 20 ohms, a controller whose own maximum resistance is 20 ohms will give very poor low speed running, not less than half the maximum (other than 'Off').

On the other hand, with a maximum of say 200 ohms in the controller, you start from 20/220 of the maximum, i.e. one eleventh, which would give a much better range of control.

[railroadbill]

Thanks, Gordon. Presumably the voltage in the circuit when the loco was running would also depend on the back emf generated as the motor turns? ie it would be different as the loco reaches cruising speed to when the loco is just starting, for a given controller setting? (so this would again depend on the motor characteristics).

 

Another factor in using these controllers is that (I've read) that a feedback controller causes problems if using a DCC chipped loco on DC.

 

cheers,

Bill

[Gordon H]

Thanks, Gordon. Presumably the voltage in the circuit when the loco was running would also depend on the back emf generated as the motor turns? ie it would be different as the loco reaches cruising speed to when the loco is just starting, for a given controller setting? (so this would again depend on the motor characteristics).

Yes, the voltage measured at the terminals of a resistance mat controller will also vary with loco speed and drawbar loading - this is why they fell from favour somewhat when the 'variable transformer' and transistorised types became available because, by contrast, their output voltages are much better regulated and therefore predictable.

[railroadbill]

Thanks Gordon,

Control equipments certainly become far more sophisticated over the years (rather like electronics in cars). One thing that is good about DCC is being able to "fine tune" the control chip to the characteristics of a particular loco. Still. I'll finish off my 1980s system as well (since that's when some of the locos were built).

 

cheers,

Bill