Want to add speed control to a locomotive powered with a 12 volt lead battery

yellow_cad

Registered
1 Jul 2020
44
4
70
California
This is a smaller 4-6-0 locomotive that currently has just an off/on switch. I just want a speed control so I can set it so it is either slower or faster when I turn it on. It is a secondary locomotive so I don't need to get too elaborate. Thanks for any help on this. Jim
 

PhilP

G Scale, 7/8th's, Electronics
5 Jun 2013
27,713
2,864
Tamworth, Staffs.
This is a smaller 4-6-0 locomotive that currently has just an off/on switch. I just want a speed control so I can set it so it is either slower or faster when I turn it on. It is a secondary locomotive so I don't need to get too elaborate. Thanks for any help on this. Jim
Do you want to change direction, at all?

PhilP.

<edit>
This from evilBay UK:


Search "12 volt DC motor speed controller" on your side of the pond..
 
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yellow_cad

Registered
1 Jul 2020
44
4
70
California
I don't believe I will change direction, but what is available. I did find the one you suggested over here. Thanks.
 

PhilP

G Scale, 7/8th's, Electronics
5 Jun 2013
27,713
2,864
Tamworth, Staffs.
I don't believe I will change direction, but what is available. I did find the one you suggested over here. Thanks.
To change direction:

You add a DPDT switch to the OUTPUT of the speed controller. - Personally, I would make it a centre-off switch. Then even if you go from one direction to another very quickly, there is still a break in the supplied voltage. No (less) chance of doing major damage to your drive-chain.


Sorry all the links are to UK sellers!


PhilP.
 

Moonraker

Registered
25 Oct 2009
980
96
South Australia
This is a smaller 4-6-0 locomotive that currently has just an off/on switch. I just want a speed control so I can set it so it is either slower or faster when I turn it on. It is a secondary locomotive so I don't need to get too elaborate. Thanks for any help on this. Jim
In the past I have used devices which cost about US$5. Go to Banggood and search for Low Voltage DC 1.8V 3V 5V 6V 12V 2A Motor Speed Controller PWM 1803B If you check their range you may find similar units with a centre off so that one knob will do speed control and reversing.

Regards
Peter Lucas
MyLocoSound
 

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Greg Elmassian

Registered
8 Mar 2014
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698
San Diego
www.elmassian.com
A little more money, but some more sophisticated options that would give more interest, also in the USA.


Greg
 

dunnyrail

DOGS, Garden Railways, Steam Trains, Jive Dancing,
25 Oct 2009
19,105
3,866
72
St.Neots Cambridgeshire UK
I have posted this before but is worth repeating. For reverting and stopping many resort to a DPDTCO switch. Whilst this works if you are in a rush to stop the train and hit the switch it is so very easy to go from forwards to reverse, a real problem if the train is flat out and a potential motor and gear train damaging possibility. This solution shown below is a safer bet using 2 x SPCO switches one each side of the Loco for access. Note that you must wire things this way, if you put the feed in the centre opposing switch locations will cause a short.

both switches forwards or reverced make the train go, one opposing and the train stops. So much easier to just flick one switch if you have that Emergancy.
9D4C9987-C0F1-4B33-BEF1-58F26C4C1B72.jpeg
 

yellow_cad

Registered
1 Jul 2020
44
4
70
California

Moonraker

Registered
25 Oct 2009
980
96
South Australia
A little more money, but some more sophisticated options that would give more interest, also in the USA.


Greg
yep, the gadget from G Scale Graphics looks a better option. The one I suggested comes from China and will take weeks to arrive with shipping charges to be added.

Peter Lucas
MyLocoSound
 

yellow_cad

Registered
1 Jul 2020
44
4
70
California
This is what I found. I don't plan to change direction often and when I do with other locomotives, I have always been careful.

Please let me know what anyone thinks of this one. The price is right; delivery is one week; it is reversible.
 

Paul2727

Registered
5 Jun 2018
589
77
The Cotswolds
Please let me know what anyone thinks of this one. The price is right; delivery is one week; it is reversible.
I tried an identical unit when looking to add speed control to a Faller railcar. It worked Ok, but drained the batteries even in the off position. That was solved by installing an additional on / off switch between the controller and the battery pack. Best to test it out of the loco first as they can get quite hot. Also ensure the input voltage is connected using the correct polarity otherwise you'll fry the unit.
Paul.
 
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PhilP

G Scale, 7/8th's, Electronics
5 Jun 2013
27,713
2,864
Tamworth, Staffs.
Paul, did yours have a switch combined with the speed control?

Take the 'one week' delivery with a pinch of salt.. Especially at the moment.
It could take longer.

PhilP
 

Paul2727

Registered
5 Jun 2018
589
77
The Cotswolds
Paul, did yours have a switch combined with the speed control?

Take the 'one week' delivery with a pinch of salt.. Especially at the moment.
It could take longer.

PhilP
Yes. The dash pot (voltage control) had an off position and the directional rocker switch had a central off position too. However both of them appear to be on the motor side of the pcb which seemed to be drawing power when connected to the power even when both switches were in the off position. Hence why I fitted an on / off switch between the battery and the input connection of the pcb. Incidentally, the directional rocker switch plugs into the pcb with a 4 pin plug and can be replaced by jumpers if a change of direction is not required. The whole set up is designed for DC only. I've got a new on here someone, if I get time I'll find it and take some pics with a battery and multimeter connected.
Paul.
NB; Mine came from e-bay.
 
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Fred2179G

Registered
20 Apr 2017
556
132
USA
Please let me know what anyone thinks of this one. The price is right; delivery is one week; it is reversible.
I have several locs with similar speed controls. I just added the one shown in PhilP's original post to a boxcab/critter. This is the underside of the removeable roof, and it has a Mylocosound card installed with speaker. In the center is the DPDT switch to reverse direction - it's hidden as a vent.


20201109_115958_roof-wiring.jpg