DCB Posted November 4, 2015 Share Posted November 4, 2015 I have mentioned my semaphore signal driver elsewhere but I append a drawing. It is dead simple and can bounce if springs are put against the limit stops. My operating arms are 13 amp plug pins attached using their own screws normally used to secure the wires, They just need a tiny hole for the operating wire. The motors are any old thing that is around. Obviously the arm is flush with the end of the armature shaft. The motor speed can be set by resistors, the length / weight of the arm and the power applied can be varied to taste. Unlike a vertically mounted point motor or a simple relay the system is stable when switched off whether the arm is up or down so a simple two way selector switch with an additional push button to activate is the way to operate. I actually use a spring two way switch on-off-on which is sprung to the middle off position. Enjoy. Attached Thumbnails Link to post Share on other sites More sharing options...
DCB Posted November 4, 2015 Author Share Posted November 4, 2015 Photos of the completed unit. This one has long motor mounting bolts with nuts to secure the motor to the backplate and the head end of the bolts acting as limit stops. Link to post Share on other sites More sharing options...
Junctionmad Posted November 6, 2015 Share Posted November 6, 2015 when we have a plethora of low cost servo modules and mounts and simple control boards, why re-invent the wheel ? Link to post Share on other sites More sharing options...
DCB Posted November 6, 2015 Author Share Posted November 6, 2015 when we have a plethora of low cost servo modules and mounts and simple control boards, why re-invent the wheel ? The driver has the potential to give a realistic operation to models of cable operated semaphore signals. I have never seen anything remotely similar anywhere and originally was going post on someone else'.s signal thread. Some times re inventing the wheel can have benefits as Hengist Pod the square wheel maker of "Carry on Cleo" fame found to his cost when the Romans introduced the then revolutionary round wheels. Link to post Share on other sites More sharing options...
Junctionmad Posted November 8, 2015 Share Posted November 8, 2015 Using a plug pin like that and ineffect slamming into the end stop at quite high speeds will quickly wear the contact brass screw and the piece will falloff or not drive. Not to mention the cost of destroying all those 13 amp plugs! There are stall motor solutions out there, but typically used gearing and electronics to control the operation In addition ,most motors even slugged down, will be too fast for realistic semaphore operation , not to mention needing protection for stuck on motors and is unsuitable for state-full operation as opposed to momentary operation I'm sorry, I view it as an incredibly crude solution Link to post Share on other sites More sharing options...
cliff park Posted November 8, 2015 Share Posted November 8, 2015 I see it as an interesting starting point. I have lots of odd small motors, with and without gearboxes. 13 amp plugs you probably throw away regularly on old washing machines, table lamps, etc. If they are rewirable I always cut them off so have a box of them. My first thought is that the length of throw doesn't look great, basically less than the width of the pin. An idea for the stall issue is to wire a lamp in series with the motor. When cold the lamp has virtually zero resistance, when the motor stalls the bulb lights up and the current drops. This would help until switched off. Something like a 12V car bulb, if the motor is around 6V is a good starting point. Even a 240V lamp may work, all those old lamps you're replacing with LEDs !! Link to post Share on other sites More sharing options...
DCB Posted November 8, 2015 Author Share Posted November 8, 2015 The next one will have the operating holes directly over the spindle (If I use a Plug Pin again) to reduce the movement which is more than I wanted for direct drive to a Ratio 00 gauge GWR home signal arm. It will have springs as stops. It is intended for momentary contact in the same way a relay operates. It needs sprung stops and fine tuning but using direct drive from the motor spindle gives a better representation of a bloke pulling a lever against a lot of resistance than anything else I have come across. Just need a motor with eccentric flywheel connected to the signal post to make the whole signal shake for that extra bit of realism. Link to post Share on other sites More sharing options...
28XX Posted November 9, 2015 Share Posted November 9, 2015 Somehow this is more railway-like than electronic servos. Electro-magneto-mechanical systems were developed to a high degree of sophistication before the silicon chip made it all obsolete. Keep at it and keep us updated. Link to post Share on other sites More sharing options...
Grovenor Posted November 9, 2015 Share Posted November 9, 2015 Real railway signal motors used a motor with a gear train to drive a crank, highly geared so the motor would do a significant number of revolutions between the on and off positions, just like a SERVO, nothing like David's device. Regards Link to post Share on other sites More sharing options...
DCB Posted November 10, 2015 Author Share Posted November 10, 2015 The intention is to make it move like a cable operated semaphore, I asked about signal bounce in Permanent way signalling and Infrastructure and got some very interesting videos of lever and cable operated lower quadrant semaphore signals operating. Motor driven semaphores were rare on full size railways, as were motor driven points in the steam era. Link to post Share on other sites More sharing options...
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