How does a DC controller work? Comparing the Morley Vector 02 and Gaugemaster Model D

[mikesndbs]

 

19th April update.  I am pleased to say that today I have adapted the Morley to perform just as well as the Gaugemaster. This is done at the cost of maximum speed (just a little) as the output was higher. I am still finalizing components and then will consider making a 'how to video' but experience and understanding in transistor isolation, component identification and a means of testing capacitors to get a balanced pair will be essential. 

This of course will totally invalidate your guarantee as well and I am certainly not going to encourage you to do that!

 

What do members think, should I make that video?

[APOLLO]

Make the video please. 

 

Lots of DCC info around, but very little DC these days.

 

Brit15

[mikesndbs]

Hello Mike,

 

I do say the following with great respect, I think that both those controllers are not quite up to it I can see that they offer pulses but no feedback. Feedback is to be found in the Gaugemaster UF, here on Scottpages or as a PDF from me, which is suitable for anyone who can use a soldering iron.

 

Here's is my homemade version in use;

 

Cheers

 

Thanks, lovely layout. I am not a fan of feedback or PWM control for anything other than shunting. Just a personal thing  

Make the video please. 

 

Lots of DCC info around, but very little DC these days.

 

Brit15

 

I'll take that as a vote, undertaking some testing this evening to make sure all is well

[Kim]

I am not a fan of PWM or feedback controllers either. The main reason is that I use a lot of coreless motors and they do not like either in the same way they don't like digital.

[mikesndbs]

I am not a fan of PWM or feedback controllers either. The main reason is that I use a lot of coreless motors and they do not like either in the same way they don't like digital.

 

With you on that, the Morley as is would be best for coreless, however the GM even gave better control with them. GM also state they are safe for coreless and I think we have to trust that.

I hope that the modified Morley might be the best of both worlds, sufficient smoothing for coreless and the pules that seem to help other motors along  

[mikesndbs]

hello Mike,

 

Do forgive me for pointing this out and correct me if I am in error, you state your aversion to pulses, yet in your video the oscilloscope trace indicates pulses as opposed to pure DC which would be a straight or ramping line. Just a bit odd I thought.

 

Cheers

 

And here is the Chinese answer to the coreless motor rip off, £2.20 incl post 5 pole, skewed armature, double shaft. In a Y8 made from cardboard including the chassis.

 

https://vimeo.com/205228610

 

 

Hi again, lovely little loco, the bigger scales always look great.

 

Just to clarify.

 

I said I don't like PWM, this is where the full DC voltage is applied to the motor at all settings and the duration of those pulses is varied to control motor speed.

I in all honesty just don't like that principle.

 

The DC pulses from the GM are in fact the result of the 100hz wave being produced by the rectifier, these are presented to the motor at a variable voltage, that increases as speed is increased.

 

Hope this makes sense, its been a long day lol

[AndyID]

Hello Mike,

 

It does indeed make sense and is exactly the same as the GM UF, No sign of a separate oscillator here:-

 

 

That's because there's a whopping great 50Hz oscillator stage-left

 

Thyristor controllers use a particular type of pulse width modulation.

[DCB]

I reckon you could get similar shunting performance from 2 X AA batteries and a two pole 5 way switch, 2 batteries forward, 1 battery forward, off, 1 battery reverse 2 batteries reverse, especially if they are on board with R/C control....

 

Now for proper main line running a 00 43XX, up a 1 in 50 down a 1 in 100 with 8 bogies and no need to touch the controls you need a Morley...

[Crosland]

I am not a fan of PWM or feedback controllers either. The main reason is that I use a lot of coreless motors and they do not like either in the same way they don't like digital.

 

The issues with coreless motors on DCC were solved 15 years ago! Any decent decoder will have high frequency PWM that will not harm a coreless motor.

[Kim]

The issues with coreless motors on DCC were solved 15 years ago! Any decent decoder will have high frequency PWM that will not harm a coreless motor.

I defer to your knowledge. I haven't fully investigated it for the simple reason I have no wish to go DCC.

[NinOz]

The DC pulses from the GM are in fact the result of the 100hz wave being produced by the rectifier, these are presented to the motor at a variable voltage, that increases as speed is increased.

 

This used to be called "pulse injection" to differentiate from PWM.

[mikesndbs]

OK so I have done all the testing and have come up with a simple change on the Morley PCB that will produce just as smooth slow speed control as the GM but also just enough smoothing for coreless and other sensitive motors.

This should mean no motor buzz/hum when starting away.

 

I will do a step by step video if there is enough interest?

[mikesndbs]

As requested here it is the follow up to my controller video, this one shows how I modified my Morley Vector Zero 2 to achieve much better slow control.

 

Edited April 27, 2018 by mikesndbs

[mikesndbs]

Another benefit of this modification seems to be that the power transistors run much cooler, thus the front panel of the controller does not become so warm J

This no doubt is due to the lower potential maximum voltage before the regulator circuit.

[DCB]

I was a bit surprised at the Bachmann 56XX performance in the Video on the unmodified Morley, I was running a Bachmann 57XX outside last evening and it was running better than that. A lot of the "Problem" I find with the Morley (and OnTrack) is the control knob is too small and requires real delicacy of control to get the speed set. I use H&M knobs and the like which are considerably bigger which helps..

 

One big advantage of the Morley over the Gaugemaster is the remote control needing only 3 wires.    It makes the wander lead much more flexible and means the hand held can be really small and you can use really chunky Stereo Audio connectors which pull out with no damage when you trip over the lead..

 

On a friends branch I have rigged up a wander lead  about five metres or so, several old Microphone leads connected together, and also a hard wired extension down to a socket at the branch terminus.  Latest addition last evening  is a second control knob hidden under a shack so we don't need to bring the remote down from the shed just for a bit of shunting.   See Pics. 

 

The controller up in the shed out of the weather is not a Morley but an OnTrack N gauge unit, ideal for shunting, no good for anything else on 00 as it gives a Bachmann 57XX about a 25Mph top speed.  The remote can also be slaved to a Morley and the Morley selected for the branch if more Oomph is required such as a visit by a Wrenn 2-6-4T.

 

I was wondering if I could gear the control knob to the pot on the remote to get finer control, maybe 2:1 which would be similar travel to a non centre off controller such as a Gaugemaster

Edited May 18, 2018 by DavidCBroad

[mikesndbs]

Guys, serious question. Do you feel my original review was fair and balanced and put both controllers in a good light?

 

Being told it's lead to layoffs, which I find hard to believe

[ejstubbs]

Afraid I can't comment on your last question, but I can report on my own attempt at the modification.

 

Since I use cab control, I wasn't too worried about the two channels on the controller matching.  In fact, I decided to 'do' only one side, so that I could have a choice between the super-smoothed DC as supplied, and the 'ripple' DC obtained from the modification.

 

What I have found is that the output voltage on the 'ripple' channel is about 1V less at full power than the as-original.  Unfortunately I didn't bother to compare the two channels against each other before attacking the controller, so I don't know whether the controller has always been like that, or if the difference was introduced by the modification.

 

The result seems to be that, using two almost perfectly matched 100㎌ capacitors, the motor on the loco I was testing with (a Bachmann Jinty) needed the controller knob to be one mark further round before it would get moving when using the 'rippled' channel.  Apart from that, the slow running behaviour was largely indistinguishable between the two channels on the controller.  Unfortunately (again) the loco I tested with wasn't a notably poor slow runner in the first place, but it was the first one that came to hand and I had limited time.  I may do some more testing with a few other locos when the time comes available.

 

I did notice that both channels seemed to have a slightly lower peak voltage in 'reverse' than they did going 'forward'.  No idea why.  I also discovered that channel 2 - the one I modified, and the one I hardly ever use in practice (hence why I chose that one to modify) - had its polarity the wrong way round.  Never noticed that before!  That was after I'd closed up the box, though, so for the moment I've just amended the label on the back on the box with a permanent marker.  Come to think, I'm not sure that I'll ever actually bother going back inside to switch the internal wiring over...

 

On which subject, if you think that your modification ended up as a bit of a bodge job, you definitely would not want to see mine!  I'm only glad that it is hidden away inside a plastic case.

 

(Out of interest, I also tested a Bachmann train set controller.  I found that it put out 19V at full power, vs 16V for the unmodified channel on the Morley controller!  It was basically a smooth, flat waveform, but with some visible short-period perturbations which weren't seen with the Morley.  Reducing the time division on the oscilloscope might have shown up more detail but, again, I was short on time.  Slow running seemed a fraction less smooth and reliable, if anything.)

Edited June 24, 2018 by ejstubbs