Author Topic: Questions: 2 Motors? Magnet switched lights?  (Read 1065 times)

Blueleader

  • Fireman
  • **
  • Posts: 43
Questions: 2 Motors? Magnet switched lights?
« on: December 22, 2018, 01:57:51 PM »
Couple of questions.
1) Can one LM3S run two motors like in an Athearn DD35? Or will I need to run two modules or switch to just one motor?
2) I'm trying to decide the best way to power and control LED lights in Rivarossi HW Passenger cars. Since I have many and keep at least 16 on the tracks I am going to use batteries to power the lights. Also to avoid flickering lights and using expensive keep alive units. Does anybody use non-contact magnetic reed switches with LED lights? If so do they work good? I ordered one that is on a board with 3 LED's, and will be powered by triple A batteries, to try it out.

Any suggestions always appreciated.

G8B4Life

  • Signalman (Global Mod)
  • Conductor
  • *****
  • Posts: 908
  • I'll think of a catchy tag line one day
Re: Questions: 2 Motors? Magnet switched lights?
« Reply #1 on: December 22, 2018, 07:58:52 PM »
1). Interesting concept.  There shouldn't be any reason electrically why it wouldn't work as long as the total max current draw of the two motors don't exceed the capability of the LM. The only thing I can think of that might throw a spanner in the works is the load sharing might not work all that well as it gets two sources of feedback that might mask what each motor is actually doing resulting in strange or erratic behavior. Two LM's might give you better control but you can't lock them together like some DCC decoders so you'd have to link (MU) them at run time.  If you have a dual motor test bed already I'd say give both ideas a go and see which one works.

2) Using magnetic reed switches to control the lights is exactly what a manufacturer here did on a couple of their locomotives. Works just fine. Just pass a magnet over the roof where the reed switches were located to turn the lights on or off. Batteries will be a pain unless the cars are easy to open up to change them. As you'd only be powering LED's I don't think you'd need an expensive keep-alive to avoid flicker but could use something much cheaper and smaller. I don't know how to calculate the capacitance required etc but looking at the "Lighted Kato Amtrak Superliner with EOT lights "schematic on this N-gineering page (https://www.ngineering.com/led_circuits.htm) 6 of those 100uF caps would cost maybe a couple of dollars at most. A bridge rectifier is also very cheap. Electrical pickup trucks however are not usually cheap - if the cars don't already come with them.

- Tim

Blueleader

  • Fireman
  • **
  • Posts: 43
Re: Questions: 2 Motors? Magnet switched lights?
« Reply #2 on: December 23, 2018, 01:28:06 PM »
You're probably right about confusion from 2 motors causing issues with the module. That leaves 2 modules or convert to one motor. It would be costly but I'm interested in using 2 modules, one per motor, and mu'ing them. I could add as much weight as possible and the DD35 should be able to pull a wall down  :D

Thanks for the info on the magnetic reed switches. Taking the shell off Rivarossi HW's is easy and if I use high quality batteries I shouldn't have to replace them more often than every 4 or 5 years. I might even try building a box to mount the batteries under the frame. I could use a flat CR battery or two and hide them in a box, since I could replace them easily I wouldn't need larger more powerful batteries. 

1). Interesting concept.  There shouldn't be any reason electrically why it wouldn't work as long as the total max current draw of the two motors don't exceed the capability of the LM. The only thing I can think of that might throw a spanner in the works is the load sharing might not work all that well as it gets two sources of feedback that might mask what each motor is actually doing resulting in strange or erratic behavior. Two LM's might give you better control but you can't lock them together like some DCC decoders so you'd have to link (MU) them at run time.  If you have a dual motor test bed already I'd say give both ideas a go and see which one works.

2) Using magnetic reed switches to control the lights is exactly what a manufacturer here did on a couple of their locomotives. Works just fine. Just pass a magnet over the roof where the reed switches were located to turn the lights on or off. Batteries will be a pain unless the cars are easy to open up to change them. As you'd only be powering LED's I don't think you'd need an expensive keep-alive to avoid flicker but could use something much cheaper and smaller. I don't know how to calculate the capacitance required etc but looking at the "Lighted Kato Amtrak Superliner with EOT lights "schematic on this N-gineering page (https://www.ngineering.com/led_circuits.htm) 6 of those 100uF caps would cost maybe a couple of dollars at most. A bridge rectifier is also very cheap. Electrical pickup trucks however are not usually cheap - if the cars don't already come with them.

- Tim

drisdon

  • Engineer
  • ***
  • Posts: 58
Re: Questions: 2 Motors? Magnet switched lights?
« Reply #3 on: December 23, 2018, 07:55:31 PM »
Scale sound systems offers a keep alive kit for $5 that might work well for the passenger cars...for a loco it says it provides 1.75 seconds so for passenger cars with just lights I would guess it would last atleast 3-5 sec.

Dan R.

TwinStar

  • Conductor
  • ****
  • Posts: 505
  • Modeling a 1961 Rock Island Twin Star Rocket
Re: Questions: 2 Motors? Magnet switched lights?
« Reply #4 on: December 25, 2018, 09:29:33 AM »
Scale sound systems offers a keep alive kit for $5 that might work well for the passenger cars...for a loco it says it provides 1.75 seconds so for passenger cars with just lights I would guess it would last atleast 3-5 sec.

Dan R.

Dan, thanks for that. I may need to pick up some of those. I also see their Coeval series of speakers are no longer offered. I think KPack reviewed these awhile back.
Jacob Damron
Modeling late 1950's Dallas Union Terminal in Free-mo+ modules

Texas Railway Modeling and Historical Society trmhs.org
trmhs.org

TwinStar

  • Conductor
  • ****
  • Posts: 505
  • Modeling a 1961 Rock Island Twin Star Rocket
Re: Questions: 2 Motors? Magnet switched lights?
« Reply #5 on: January 06, 2019, 02:00:38 PM »
Scale sound systems offers a keep alive kit for $5 that might work well for the passenger cars...for a loco it says it provides 1.75 seconds so for passenger cars with just lights I would guess it would last atleast 3-5 sec.

Dan R.

Wouldn't 1.75 seconds be more than enough? It's generally small interruptions in power on a Free-mo layout that are split seconds. I have 6 Proto GP7's that will be converted and this seems a lot smaller than the other options and may fit into the narrow hood better.
Jacob Damron
Modeling late 1950's Dallas Union Terminal in Free-mo+ modules

Texas Railway Modeling and Historical Society trmhs.org
trmhs.org

Michael

  • Fireman
  • **
  • Posts: 17
Re: Questions: 2 Motors? Magnet switched lights?
« Reply #6 on: January 16, 2019, 08:28:25 PM »
I've installed 1 module in an O scale locomotive with two motors (electric trolley loco). I used a DCC wiring diagram. The two motors draw about 3/4 of an amp. The engine runs fairly well.

BruceRogers

  • Engineer
  • ***
  • Posts: 95
Re: Questions: 2 Motors? Magnet switched lights?
« Reply #7 on: January 17, 2019, 08:56:17 AM »
I have asked Ring about running two motors as in the Athearn Genesis DDA40X. The LM module will read the current of both motors as the value for load sharing. You won't need to use 2 LM modules to power the locomotive.

Blueleader

  • Fireman
  • **
  • Posts: 43
Re: Questions: 2 Motors? Magnet switched lights?
« Reply #8 on: January 19, 2019, 09:28:20 AM »
Hey thanks. That's good news. Time to get wiring. When I get it running I'll post a video on the RPUG FB group. First I have to finish mudding and painting the sheetrock ceiling I just put up in my 18.5x11' Model room. Sanding mud is my most dreaded part of building/remodeling a house  :o

I have asked Ring about running two motors as in the Athearn Genesis DDA40X. The LM module will read the current of both motors as the value for load sharing. You won't need to use 2 LM modules to power the locomotive.