Hello everyone,
I have recently installed some homemade code 100 turnouts that a friend had built for me.
They replaced some older turnouts that I was having issues with.
These turnouts were controlled by servo motors.
Now I am finding that these sevo motors don’t quite have what it takes to throw the points.
What do you poeple have for suggestions for a more robust servo/powered motor or mechanical means to throw my code100 turnouts?
Thanks
cn1762
Are the points solid or hinged? High frog number or low?
A low frog number with short points rails in the thicker Code 100 will need hinged points. Longer points, even in Code 100 rail, should be bendable with all commercial turnout motors. Maybe your throwbars are rubbing to hard on something, the rails above them or the surface below them.
What are you using now to move the points? What amperage/voltage to they use?
I’ve been building the 3-way household wiring switch-powered manual throws with some success. Use threaded rod and maple dowels for the linkage to throw them and you should be good.
I’ve never done anything with servos. This question is based on my Tortoise experience, where a wide range of voltage on the supply is acceptable. It’s also the case when you add one too many to the power supply that’s supporting say, 2 or 3 dozen, then they all want to just go ugh and not move. Time to add on another power supply. They’re just milliamps, but the eventually add up to the max the supply is capable of supporting. But that’s probably not your issue unless it applies to serrvos also and you recently added more switch machines to the power supply supporting the newly installed turnouts?
The other thing that can sometimes give more oomph to your throw with the Tortoise is to turn up the voltage some. Less is better, probably longer life, but sometimes you need more juice is all. Again, not sure if that applies to servos, but might be enough to get them to throw if it applies similarly.
What size wire are you using between the servo and the throwbar? It may just be a matter of using stiffer wire so it bends. Code 100 rail plus short points (small frog number) can be pretty stiff - you might have to use a larger servo than the SG90 type.
As for comparison with Tortoise - you can’t just crank up the voltage for a servo. The voltage is related to the pulse from the controller - there are 3 wires, +, -, and signal. Servos have a torque rating, and are not designed to stall. Instead they move per the signal, which is a varying pulse, when it’s even, the servo is centered, when it shifts to one side or the other, the servo moves until the feedback potentiometer that’s part of the mechanism alters the on board circuit to match the same pulse pattern. Then the motor is stopped. If the servo is pushing against too great a load (not enough force) it will never reach the commanded endpoint, and chatter constantly, or until the motor burns out or the controller circuit does. The SG90 servos seem fine for HO Code 83 and smaller, hinged or solid points, but they might just not have enough oomph for code 100 solid points. But SG90’s are the smallest ‘standard’ servo (there’s at least one size smaller, in fact my plane has two of them, but they aren’t fully enclosed like SG90’s and the larger ones). The next size up from the SG90 size is still a fraction of the size of a Tortoise and probably is more than enough for the Code 100 points. The SG90 type is a micro, there is a mini and a standard. Mini should be enough, but even a standard size servo is half or less the size of a Tortoise.
–Randy
I put a homemade gauntlet turnout, code 100 M.E. rail into service with Tortoise switch mach. It has short stiff point rails, but .039 spring wire did the trick. I also lubed and burnished the PC throwbar and tops of the ties where the point rails move across them with molykote powder, but Kadee Greas-em would work too.
Good luck and regards, Peter