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Post by steveoncattailcreek on Jun 28, 2024 17:29:12 GMT
Since I'm nearing the end phase of my scratch build of the old Cambridge train station (see below),  I'm in search of some advice on my next project -- specifically, my plan is to model the nearby Cambridge Creek bridge:  What I need is a lead on both a source for an appropriate slow speed geared low voltage DC motor (or perhaps two, one for each side, if that's easier to arrange than transferring lift power between the sides), and the bits and pieces to control it (or them). For control, I'm envisioning a DPDT center-off momentary toggle, wired to reverse the feed polarity depending on which direction the toggle is pushed, and two limit-of-travel normally closed contact switches, one for raised and one for closed (or four, if two motors are used), wired in series with one of the power feeds and positioned to activate when the bridge is in either fully closed or fully open position. The NC contacts of each of the pair of switches would be bridged by diodes (in opposite polarity), so depending on the polarity of the feed (as determined by the DPDT toggle), only one contact switch will be able to interrupt the motor at any given time. I'm also open to ideas on how to construct the bridge section pivots, and how best to connect the motor(s). Ideally, I'd love to find that there's a pre-built mechanism I can adapt for this project, or something I can kit-bash into a reasonable facsimile. Any suggestions or leads greatly appreciated, and thanks!  |
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Post by firewood on Jun 28, 2024 19:19:39 GMT
Beautiful job on the station!
You can find several slow speed drives in Amazon under a search for ‘ gearmotor ‘.
After just fixing up a Lionel 345 conveyor loader, it occurred to me a couple of those might work too. You could hook maybe them uo to a small train set transformer and set the throttle for slow speed.
Dave
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Post by curtis on Jun 28, 2024 22:40:41 GMT
Gutzy project. The station is great. Good luck with the bridge project
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Post by Adam on Jun 29, 2024 2:49:14 GMT
Great job on the station. Looks really nice!
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Post by steveoncattailcreek on Jun 29, 2024 5:02:38 GMT
Beautiful job on the station! You can find several slow speed drives in Amazon under a search for ‘ gearmotor ‘. After just fixing up a Lionel 345 conveyor loader, it occurred to me a couple of those might work too. You could hook maybe them uo to a small train set transformer and set the throttle for slow speed. Thanks, Dave! I'm working on the station model to possibly add to the Cambridge RFC train garden, and it's been my most ambitious scratch build project to date. I still need to light and landscape it, and I have a few more tweaks to do appearance-wise, but it's been a fun project, even if challenging at times! I have a couple of N20 geared-down motors, a bunch of pulleys, and a pack of limit switches on order by slow boat already, but I'll keep your suggestions on hand if I'm not satisfied with my experiments. Thanks again!
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Post by steveoncattailcreek on Jun 29, 2024 5:08:02 GMT
Gutzy project. The station is great. Good luck with the bridge project Thanks, Curtis! Yeah, it was my first effort towards modeling the Cambridge Creek area of my hometown for the RFC train garden, and I had to stretch my skill set into some new areas I'd never had occasion to visit before, but it seems to be coming together! The bridge project is going to be even more of a challenge, but hey, that's what makes the hobby so much fun! 
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Post by steveoncattailcreek on Jun 29, 2024 5:19:08 GMT
Great job on the station. Looks really nice! Thanks, Adam! It's been a challenge, but so far I'm liking how it's coming out. I still have to make another visit to the prototype to take pictures of the actual interior, in order to fabricate shadowboxes behind each window and door in an effort to replicate the actual view in each opening (and to hide the buck converter and wiring for the LED lighting that'll be inside!). I also need to attach the station to the base, which will likely just be painted and scored to resemble concrete paving, but I may add a few flower boxes and/or other landscaping touches.
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Post by harborbelt70 on Jun 29, 2024 10:30:30 GMT
Beautiful job on the station! You can find several slow speed drives in Amazon under a search for ‘ gearmotor ‘. After just fixing up a Lionel 345 conveyor loader, it occurred to me a couple of those might work too. You could hook maybe them uo to a small train set transformer and set the throttle for slow speed. Dave
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Post by steveoncattailcreek on Jun 29, 2024 14:42:03 GMT
You can find several slow speed drives in Amazon under a search for ‘ gearmotor ‘. Well, there's considerable variation among the descriptions of the N20 motors I reviewed, but they all amounted to the same thing -- a metal gear reduction low voltage DC motor of various output RPMs, as low as 5 RPM. I ordered a couple to experiment with, so we'll see . . . Yes, the motor is very small (appears to be under an inch wide, less than two inches long including gearbox but excluding the shaft), but with the reduction it should have plenty of torque to lift a counterweighted bridge section. My current plan is to use two motors to separately drive the two sections -- it's even prototypical, since I always noticed the slight variation in opening and closing times! Anyway, more bits and pieces on their way to play with -- wish me luck! 
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Post by harborbelt70 on Jun 29, 2024 16:59:30 GMT
Is that what they are called? Well, I never - but I recently found them under "gear reduction motor" and they are basically DC smoke unit motors fitted to a tiny gearbox. Not sure if the ones I got would drive raising a bridge section but some are designed for drones so I am sure you'll find one with sufficient torque for that purpose. Mine are rated at 12 VDC at various RPMs from around 100 to 600+ which might be too fast for your purposes without a further gear reduction. Well, there's considerable variation among the descriptions of the N20 motors I reviewed, but they all amounted to the same thing -- a metal gear reduction low voltage DC motor of various output RPMs, as low as 5 RPM. I ordered a couple to experiment with, so we'll see . . . Yes, the motor is very small (appears to be under an inch wide, less than two inches long including gearbox but excluding the shaft), but with the reduction it should have plenty of torque to lift a counterweighted bridge section. My current plan is to use two motors to separately drive the two sections -- it's even prototypical, since I always noticed the slight variation in opening and closing times! Anyway, more bits and pieces on their way to play with -- wish me luck!
 This suits my purposes as the object is for these to drive a pair of roof fans in my project written up on the UP 2006 thread. I am having to toy around with the voltage applied to these to get the speed in line with what I regard as suitable, but I have seen others designed to fly quadricopter drones. Mine are made for certain battery powered toys and I suspect there is a huge number of choices available if you search for them. P.S. I got no insight from looking at my Lionel bascule bridge - a display item although it works - because the gears are huge and mostly concealed so I can only see the main one. I also think that the motor is AC and it certainly is noisy!
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Post by steveoncattailcreek on Jun 29, 2024 17:15:39 GMT
Anyway, more bits and pieces on their way to play with -- wish me luck!
I am having to toy around with the voltage applied to these to get the speed in line with what I regard as suitable, but I have seen others designed to fly quadricopter drones. Yeah, at least from the specs on-line, the output rotation rate of the N20 motors I ordered is pretty directly proportional to the feed voltage, so with an adjustable buck converter I hope I'll be able to 'dial in' an appropriate speed. If not, I'll go with the proverbial Plan B . . .
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Post by firewood on Jun 30, 2024 19:02:50 GMT
Beautiful job on the station! You can find several slow speed drives in Amazon under a search for ‘ gearmotor ‘. After just fixing up a Lionel 345 conveyor loader, it occurred to me a couple of those might work too. You could hook maybe them uo to a small train set transformer and set the throttle for slow speed. Dave I think it’s a generic term as they usually come as a manufactured unit - ‘ gearhead motor’ might work too. Dave
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