DC Motor Speed Controller,6-28V 3A

Discussion in 'DC Control' started by paul_l, Jul 9, 2020.

  1. paul_l

    paul_l Staff Member Administrator

    Messages:
    9,820
    Likes Received:
    5,866
    Joined:
    Dec 5, 2015
    What me in the DC Control section, am I lost :scratchchin:

    Well no, since moving over to O gauge, the only running loco's I have are small RTR 0-4-0 or 0-6-0 tanks, and fitting a decoder in was simple - just drop in a 4mm designed decoder and all was OK.

    Now I've having a go at kit building I need to run in the motor & gearbox and determine the current draw of the loco before fitting a decoder (most 4mm decoders are designed for between 0.5 & 1.0 A steady consumtion with peaks upto approx 1.5A).
    My old H&M Duette can provide a max of 2A before thermalling, and my NCE PowerCab is rated at 1.5A. I therefore needed a meatier DC controller to allow me to run the loco in, determine the current consumption (average and stall currents). I could have purchased a newer stand alone controller, but for just running in seemed a bit excessive. I did consider building a controller using a power transistor - real old school, and started looking for an example circuit and bits, then stumpled upon this from Amazon

    DC Motor Speed Controller,6-28V 3A PWM DC Regulator Speed Electric Motor Controller with Switch Function

    £6.39 and three days later this arrived


    I already have a 12V 4A DC power supply - but plenty are available from the likes of Amazon or Ebay for around a tenner.

    Connect the 12V supply to the + & - terminals, and the track to the remaining terminals and it's a runner.

    I will be making a face plate which will include a voltmeter and ameter (cost was approx £3) plus a switch to choose between DC or DCC, so I'm looking at a full solution for approx a tenner (or £20 if you include the psu).

    This is a PWM (pulse width modulation) based controller, so should give good slow running properties, we'll see, and I'll post up the progress.

    Paul
     
  2. gormo

    gormo Staff Member Administrator

    Messages:
    5,966
    Likes Received:
    4,062
    Joined:
    Dec 5, 2015
    G`day Paul,
    A nice little buy there maybe.....:scratchchin:
    I tried something similar to this quite a few years ago and found that the PWM frequency did not suit the locos I had.
    They emitted a whine when the power was applied and the frequency was not adjustable so I gave up on that particular circuit.
    However as there are so many of this type of circuit available, the probability of the one you have being perfectly OK is very high.
    I think the one I had may have even been a dud !!!.....:scratchchin:
    :cheers::tophat:Gormo
     
  3. paul_l

    paul_l Staff Member Administrator

    Messages:
    9,820
    Likes Received:
    5,866
    Joined:
    Dec 5, 2015
    Hi Gormo

    PWM is better suited to cored motors than coreless, but as this is intended for running in loco's on the rolling road, I'll learn to put up with it or turn the music up louder :avatar:

    Just done the first draft of the face plate

    upload_2020-7-10_0-17-46.png

    Large aperture is for the LCD voltmeter / ameter, center hole is the direction switch, and the final hole is for the pot.

    Forgot to mention, the pot has an off position when turned fully anti-clockwise, the direction rocker switch also has a center off.

    I will print it up tomorrow and see how it looks.

    Paul
     
    jakesdad13 likes this.
  4. paul_l

    paul_l Staff Member Administrator

    Messages:
    9,820
    Likes Received:
    5,866
    Joined:
    Dec 5, 2015
    Nuts - It won't fit on the build plate :facepalm: - definately time for bed

    Paul
     
    Andy_Sollis likes this.
  5. gormo

    gormo Staff Member Administrator

    Messages:
    5,966
    Likes Received:
    4,062
    Joined:
    Dec 5, 2015
    All will become clear after a good nights sleep.......:avatar::avatar:
    :thumbs:
     
  6. paul_l

    paul_l Staff Member Administrator

    Messages:
    9,820
    Likes Received:
    5,866
    Joined:
    Dec 5, 2015
    OK version 2 of the faceplate

    upload_2020-7-10_21-7-5.png

    Now this is pretty much full size of the build plate, the print has started, we'll see how it goes.

    Paul
     
    Andy_Sollis likes this.
  7. paul_l

    paul_l Staff Member Administrator

    Messages:
    9,820
    Likes Received:
    5,866
    Joined:
    Dec 5, 2015
    And the print is ready (I forgot to post the reply before taking my daughter back home :facepalm:)


    Just need to let it cure then try the bits for fit.

    I intend to spray the faceplate, not sure what colour - yet.

    Paul
     
    Andy_Sollis and Kimbo like this.
  8. Toto

    Toto I'm best ignored Staff Member Founder Administrator

    Messages:
    15,419
    Likes Received:
    3,842
    Joined:
    Dec 5, 2017
    Umm..... black errrrrr .... make that white ...... no ..... black. :avatar:
     
  9. gormo

    gormo Staff Member Administrator

    Messages:
    5,966
    Likes Received:
    4,062
    Joined:
    Dec 5, 2015
    Neat.......:thumbs::thumbs::thumbs::thumbs::thumbs:
    :cheers::tophat:Gormo
     
  10. paul_l

    paul_l Staff Member Administrator

    Messages:
    9,820
    Likes Received:
    5,866
    Joined:
    Dec 5, 2015
    Assembled looks like



    Modifications, I think I need to move the display unit in from the edge and reduce the verticle size of the display aperture, somewhere safe I have a different type display unit, which may be smaller as I would like a bit more panel around the edges to allow for the ham fisted oaf who will cut the aperture for it to fit in.

    I have spunt the controller board through 180 degrees from the photo, but think I will make panel higher as well - currently 60mm high, I'll increase it to 66mm (max size is 68 - but the edge wouldn't be as well defined as can be seen in the length which is at the max 120).

    Or I could split them up on to separate panels :scratchchin:

    Paul
     
    Rob Pulham and Andy_Sollis like this.
  11. paul_l

    paul_l Staff Member Administrator

    Messages:
    9,820
    Likes Received:
    5,866
    Joined:
    Dec 5, 2015
    Found it

    20200711_093824.jpg

    Back to the drawing board

    Paul
     
  12. paul_l

    paul_l Staff Member Administrator

    Messages:
    9,820
    Likes Received:
    5,866
    Joined:
    Dec 5, 2015
    OK version 3

    Toto had suggested that I made it thicker, so now 3 mm thick, the recesses remain 1 mm thick for the retaining clips.

    upload_2020-7-11_10-29-3.png

    Also added reinforcing strips

    upload_2020-7-11_10-27-50.png

    Now off to print it - back in an hour or two, SWMBO has a list to be done.

    Paul
     
  13. gormo

    gormo Staff Member Administrator

    Messages:
    5,966
    Likes Received:
    4,062
    Joined:
    Dec 5, 2015
    I still reckon it`s neat !!!!.......:thumbs::thumbs::thumbs::thumbs::thumbs:
    :cheers::tophat:Gormo
     
    Andy_Sollis likes this.
  14. paul_l

    paul_l Staff Member Administrator

    Messages:
    9,820
    Likes Received:
    5,866
    Joined:
    Dec 5, 2015
    This time printed in Grey resin

    General comment, the grey stinks more than the green resin.

    Front view


    and the rear view


    assembled

    upload_2020-7-11_13-43-47.png

    Wiring diagram to follow

    Paul
     
  15. paul_l

    paul_l Staff Member Administrator

    Messages:
    9,820
    Likes Received:
    5,866
    Joined:
    Dec 5, 2015
    OK so I couldn't resist, I've made the case as well

    upload_2020-7-11_16-17-31.png

    The front fits into the recess, like wise the rear has ventilation slots with a recess to hold a fan if needed - I may need an additional hole for air intake :facepalm:, oh well we'll see, the print has started and is due to take 10 hours

    Paul
     
    Rob Pulham, Andy_Sollis and Keith M like this.
  16. paul_l

    paul_l Staff Member Administrator

    Messages:
    9,820
    Likes Received:
    5,866
    Joined:
    Dec 5, 2015
    view from the back

    upload_2020-7-11_16-21-57.png

    Paul
     
  17. Toto

    Toto I'm best ignored Staff Member Founder Administrator

    Messages:
    15,419
    Likes Received:
    3,842
    Joined:
    Dec 5, 2017
    The grey look better even though it will get painted.
     
    Andy_Sollis likes this.
  18. paul_l

    paul_l Staff Member Administrator

    Messages:
    9,820
    Likes Received:
    5,866
    Joined:
    Dec 5, 2015
    8h52m later (actually 14h as I was in bed)



    And with front fitted


    Sides will need a little sanding before paint


    Wiring next

    Paul
     
  19. paul_l

    paul_l Staff Member Administrator

    Messages:
    9,820
    Likes Received:
    5,866
    Joined:
    Dec 5, 2015
    Well I'm quite chuffed with this, so I decided to splash out on some connectors, rather than have wires just popping out of the back.

    For the power supply 5 x 2.5 mm connectors,

    [​IMG]

    and for the track 5 x 2.1 mm connectors - I will use the screw sockets as above, but with terminal adapter plugs to the track so I can easily change polarity

    [​IMG]

    Paul
     
    Andy_Sollis, Rob Pulham and steve like this.
  20. Kimbo

    Kimbo Staff Member Moderator

    Messages:
    2,956
    Likes Received:
    2,227
    Joined:
    Dec 13, 2015
    Very nice Paul, connects will be the finishing touch....when can we start to order them from you :thumbs: Kim
     
    paul_l likes this.

Share This Page