While looking at YouTube films on model railways I came across this one https://youtu.be/T64lhCwN9Ws from Budget Model Railways in which they promote a very cheap controller for which they make a 3D printed housing. Does anyone with knowledge of electrics and 009 loco's have an opinion as to whether this controller is a good idea?
An interesting link Trevor, and plenty more where it came from - Budget Model Railways: https://plus.google.com/u/0/+BudgetModelRailways (https://plus.google.com/u/0/+BudgetModelRailways)
In principle the controller, or something similar built from what is available at the time on ebay should work. Some caution may be prudent as there are a couple of things at least that might cause problems. The first is the PWM frequency and if that is too low then it may cause overheating in some models and the second is current limiting (or lack of) in the case of shorts or overloads.
Given the subject of the website/channel a budget controller for a budget model railway is an excellent idea.
This looks like the controller: https://www.ebay.co.uk/itm/DC-6V-28V-3A-PWM-DC-Motor-Speed-Controller-Forward-Reverse-Control-With-Switch/272667994451?hash=item3f7c476953:g:~TYAAOSwuMZZB~qJ:rk:7:pf:0
(https://www.ebay.co.uk/itm/DC-6V-28V-3A-PWM-DC-Motor-Speed-Controller-Forward-Reverse-Control-With-Switch/272667994451?hash=item3f7c476953:g:~TYAAOSwuMZZB~qJ:rk:7:pf:0)
The PWM frequency is not given and the current is quoted as 3 A max so a fuse might be a good addition.
Thanks for posting the link, Trevor - very interesting. The controller is a quarter of the price of the much-acclaimed Minitrains one but I wonder if there's much difference inside the box? While it appeared to work fine with the models he demonstrated I wonder if it will suit our little motors equally well?
Further comments from those with electronic know-how are awaited...
David.
If it is a PWM (Pulse width modulation) controller it will be of no use for locos with coreless motors (e.g. Bachmann Baldwin). The slow-running characteristics will be nil and the controller will be a waste of time and money, possibly causing extensive damage to the motors. The Minitrains controller is also a PWM unit and will not work satisfactorily with coreless motors. I know it has been said many times before but just stick with Gaugemaster.
I've been digging around and another possible "quirk" more than serious problem occurred to me. Some cheap PWM controllers do not cover the full range of output voltages from 0% to 100% of the supply. Not reaching fully on is no major problem here, but not being able to reduced the speed to fully off may be. Some modern models will creep along at very low voltages.
Another listing for what appears to be the same speed controller: https://www.ebay.co.uk/itm/DC-6V-28V-3A-PWM-DC-Motor-Speed-Controller-Forward-Reverse-Control-With-Switch/272667994451?hash=item3f7c476953:g:~TYAAOSwuMZZB~qJ:rk:7:pf:0 (http://ttps://www.ebay.co.uk/itm/DC-6V-28V-3A-PWM-DC-Motor-Speed-Controller-Forward-Reverse-Control-With-Switch/272667994451?hash=item3f7c476953:g:~TYAAOSwuMZZB~qJ:rk:7:pf:0) states 5% - 100%. This might be enough to make a loco with good motor crawl.
Another listing states the board includes a 3 A fuse: https://www.ebay.co.uk/itm/6V-12V-24V-28V-3A-80W-DC-Motor-Speed-Controller-PWM-Speed-Adjustable-Revers-SS/322817966741?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D52543%26meid%3Dbe33798924de4c23a98bb97e295aee2c%26pid%3D100005%26rk%3D5%26rkt%3D12%26sd%3D272667994451%26itm%3D322817966741&_trksid=p2047675.c100005.m1851
(https://www.ebay.co.uk/itm/6V-12V-24V-28V-3A-80W-DC-Motor-Speed-Controller-PWM-Speed-Adjustable-Revers-SS/322817966741?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D52543%26meid%3Dbe33798924de4c23a98bb97e295aee2c%26pid%3D100005%26rk%3D5%26rkt%3D12%26sd%3D272667994451%26itm%3D322817966741&_trksid=p2047675.c100005.m1851)
It is not obvious on the board (i.e. I've not spotted it). It could be a resettable "polyfuse" I suppose, but a smaller value would be better for 009 locos.
Quote from: rod335 on October 28, 2018, 07:48
If it is a PWM (Pulse width modulation) controller it will be of no use for locos with coreless motors (e.g. Bachmann Baldwin). The slow-running characteristics will be nil and the controller will be a waste of time and money, possibly causing extensive damage to the motors. The Minitrains controller is also a PWM unit and will not work satisfactorily with coreless motors. I know it has been said many times before but just stick with Gaugemaster.
I'll have to disagree with Rod here. I think he is making too much of a generalisation. Coreless motors work perfectly well with (the right) PWM controller. Low frequency PWM and the sort of pulsed controllers that use the rectification of the mains can cause problems of overheating. PWM can give excellent slow speed regulation (see DCC decoders which are all PWM). The problem can occur with some old (or old design) feedback controllers where the feedback sensing was not designed with coreless motors in mind.
Even low frequency PWM (of the right kind in the right environment) need not burn out motors. I made a little T-gauge demo. The video is rather old and the jitter is due to the camera and the compresssion needed at the time to post on YouTube.
https://www.youtube.com/watch?v=kw8SCKRFH_U
The few that I have won't go down to zero volts. I have a Grafar 08 that won't stop on these controllers. Seems OK for iron core motors like Mashima though. I'm also getting sparks when a wheel back shorts out on a point blade.
Mal.
Sorry Graeme, you cannot have tried a Minitrains controller with a Bachmann Baldwin. Even on the lowest setting the loco leaps off like a scalded cat. The same loco on a Combi is perfectly controllable. At an exhibition a couple of years ago I was next to Richard Holder and on Sunday afternoon we ran some of my locos on his Wantage layout. Perfect on his Combi, decidedly jerky and noisy on his Pentroller. Everyone else who I know agrees that coreless motors do not like either feedback or pulse power of any sort. I do not know the technical reason why, nor, indeed, wish to. But it is nonetheless true.
Rod - whatever the Minitrains controller does to a Bachmann Baldwin cannot be extrapolated to PWM in general and all locomotives with coreless motors. (I did say "the right" PWM controller.)
I don't know what the circuit for the Minitrains controller is, but I suspect it is optimised for use with their locos with flywheels in them and so just maybe uses low frequency pulses.
In this thread we are talking about a generic PWM electronic speed controller from ebay and not what what some model train controller manufacturers may choose to call PWM. One ebay speed controller similar to the one linked to quoted 20 kHz frequency, which should be high enough for most coreless motors.
I did not intend my comments to be restricted purely to the Minitrains controller. It is my experience that ALL pulse power controllers of any sort do not work well with coreless motors. I do not, and indeed do not wish to, know why. But I know it to be true. Same with feedback. Since the much loved Gaugemaster stuff works equally well with both coreless and conventional motors and it seems apparent to me that coreless motors are going to be used increasingly, it seems a bit pointless to adopt a control system that is incapable of operating both types of motor satisfactorily. But you pays your money and you takes your choice.
I should have checked the Minitrains web site - they say the PWM frequency is 16.625 kHz, not quite the "silent drive" of high frequency PWM in DCC decoders as people below a certain age should hear it. http://www.minitrains.eu/mt-acc.html (http://www.minitrains.eu/mt-acc.html) but certainly not low frequency as I thought it might be.
As far as I know, all DCC and radio control systems use PWM control as it is the only way to get power control into a very small package. These seem to work OK with coreless motors though.
I think the frequency of the PWM will be important here and the DCC and Radio Control ones are likely to be high frequency whereas the older design mains driven track controllers are more likely to be mains frequency or similar, ie very low frequency.
It is true though that some of the cheaper PWM controllers do not cut the power completely and so this could cause problems. Any system with full two way control (ie forward and reverse on the same knob, rather than speed control and separate direction switching) is likely to have a true zero power position between the forward and reverse settings. Some of the cheap controllers on ebay etc. are motor speed controllers not loco controllers and are designed to give speeds from slow to fast but not to give an off position.
Frank
I think there is a fundamental problem regarding controllers for 009.
Put simply because of the wide variety of motors used in 009 locos no one controller is ideal for all.
A controller that will work well with a loco with a modern coreless motor may not work well at all with an old Arnold chassis.
A controller that works well with an old Arnold chassis may not work well at all with a loco with a modern coreless motor.
The solution is simple, stick to one type of motor in all your locos and then have a controller that works well with them.
My problem is in common with most 009 modellers I have a wide range of types of motors in my locos!
I have a layout that has a simple 9v AC transformer, a bridge rectifier, an old H&M thermal cut out, a centre off direction switch and a very nice wire wound 500ohm 5 amp rated rheostat with a completely isolated section at its lower end of travel. This is as
Well...
No I'm not going to say anything...
Oh go on Hugh !
There was a discussion on NGRM regarding these as a result of which I bought two from China for about a fiver each .I must admit I have only used them on two isolated lines on my layout (the main part all ready having quality controllers ) and these with limited use so far seem fine with Kato tram chassis with good control .
At least if they do burn out motors ,it won't cost me much to replace kato chassis !
I have used some similar boards and they all seem to work well. I do suggest that you power it with a short circuit protected power supply that is not too powerful. A 1 Amp PSU should be plenty. If you are not too sure of your PSU you could add a cheap voltage regulator board that can provide the necessary protection and provide a stable voltage to the controller.
Alan Hamer (who, unlike me, understands these things) has now assembled one of these controllers from the component parts as described by Trevor and preliminary reports are very positive. He has a test track with digital displays showing the current and voltage for any combination of motor/loco and controller which is very useful.
I am hoping he will post some of his findings here in due course for the benefit of all. Our future TLO might want to talk some more with Budget Model Railways.
David.
I built a cheap controller following the instructions in a 1980 Model Railroader, and it outclasses all model railway manufacturers' controllers. Cheap is not necessarily bad.
I just started a multi-part reply in the thread "Old controllers - new motors = problem?"; and I'll cover the PWM versus coreless question there.
PWM in the audible spectrum (12 to 27 000Hz) can cause a nuisance as you hear the 'rattle', but that doesn't mean that outside this spectrum it's all fine; just because you can't hear it, doesn't mean there is no damage happening.
An interesting discussion. Firstly to lay a myth PWM contollers will work with coreless motors. According to the Laws of Physics, specificallly Maxwells laws of electromagnetism, there is every reason why they should. In fact ariel drones use coreless motors with PWM control, DCC loco use PWM as well and they seem to work OK. I've built one of these Budget contollers and I tested it against Minitrains and Gaugemaster controllers at the Dorset Members day last week. In simple terms there was no observable difference in performance between it and the Minitrains but there was a slight difference between these 2 and the Gaugemaster. Only to be expected as they are different technologies. All these devices ran old open frame motors, modern small motors and a tiny coreless motor without problem drawing virtually the same power with each different motor. The Budget Contoller has a centre off DPDT switch to control direction and the potentiometer has a click off as well so it shuts down completely to stop a loco.
However compared with older motors coreless motors have a very low rotating mass so effectiviely have no flywheel. This is why they respond to control changes so quickly and why if you want more realistic locomotive control with a degree of inertia you need to fit a flywheel. An overload cutout would be a good idea but if you use a low output transformer, say 1000ma, or one giving less than 12v the controller cannot put out more than this, which would protect most motors. For the money it would be hard to go wrong. I have no connection with Budget Model Railways other than as a satisfied customer.
One problem I have observed with some of the cheaper controllers and older type locos is that they will not start the locos at slow speeds. You have to turn the speed up higher to get the loco moving and then turn it back down again to get the loco to run at a slow speed. This is ok for a circuit layout but useless for shunting.
Brian Meldon
Hochwald, Du hast recht! Yes, you're right!
However, high frequency has other effects, think high-frequency welding. So, while PWM and coreless may work together fine, there might be implications. And of course, the same applies with regards to ANY motor, not just coreless.
As I said, I'm working my way through the technicalities, while trying to keep it simple. But I chose a different thread to debunk the myths (look at old controller - new locos = problems? in this forum).
This thread is about our views on cheap controllers, and I stand by my statement: cheap can be brilliant. My DIY controller cost about
Quote from: Leprechaun on December 10, 2018, 18:44
Brian, there are 3 potential reasons for engines not being able to run slow:
1. Cheap motors with high magnetic resistance, combined with insufficient gear ratio. Take the motor out and turn it by hand; if it 'snaps' from pole to pole, i.e. doesn't turn smoothly, it is one of those (practically all older 3-pole anchors will do that, but it should not require much force; take an old Fleischmann H0 pancake motor and its clone, the Lima pancake motor, and you will notice the difference).
2. Insufficient gearing (the Minitrix dock shunter {=T3) is an example of that).
3. A controller that does not regulate down to zero (most commercial transformer-controllers jump from 0 to circa 2V before commencing a 'smooth' voltage rise, older Maerklin transformers jump to circa 6V!!!).
Ei gude wie vom
Waldschrat ;D
I think you have missed the point.
It is not that the chassis will not run slow, it is that they will not start slow.
The problem it is getting the locos moving from stopped.
The controllers involved do start from a low voltage it is just that the locos do not move until they are turned up higher.
Once the locos are running the controller can be turned back down and the locos will run slow.
I have seen this happen with these cheep controllers and others.
In regards to the older open frame motors it is perhaps worth mentioning that the vast majority of 009 locos use these older type of motors, it is only chassis made in the last few years that do not.
It is quite easy to get a cheap controller to work well with these newer motors.
It is also quite easy to get a simple controller to work well with the older motors.
However, it is virtually impossible to get a controller to work well with both types.
Brian Meldon
Dear Brian,
Maybe you're right, I don't have the full facts, of course cheap can be cheap & nasty, but so can expensive. ???
But then again, I can repeat only what I said before: this thread is about our views on cheap controllers, so we don't have to agree: you have your views, and I have mine. ::) ::) ::)
That said, I stand by my statement:
Cheap can be brilliant; (and expensive can be cra