Railway Engineering's Rotor Motor switch machine - a review

Hi, All!

I recently ordered some Rotor Motor switch motors from Railway Engineering -

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- and duly installed one (so far) on my layout. I was attracted first by the apparent ease of installation, and secondly by their price (US$9.95). An additional attraction was what was apparent from the pictures on the site - a very compact and elegantly simple design.

These motors are NOT stall motors, though one point on their site indicates that they are. They move the points over a generous throw range, and then have cut-off contacts which kill the power to the motor.

The unit has only two moving parts: a small 5v DC electric motor with a worm on its shaft, and a worm gear mounted on a hollow shaft. The contacts are soldered to the shaft. The only drawback that I can see to this machine is that it would be difficult to mount it anywhere but directly under the turnout throw bar. Could be done, perhaps, but it wouldn't be easy. It is so compact, however, with a 2" x 1.25" footprint, that one can usually find a way to mount it under the turnout....

The unit is mounted with a single wood screw through the frame into the layout. I have mounted mine to a piece "hobby board about 3/16" thick, then glued it to the bottom of the foam layout base with a "Liquid Nails for foam"-type product. It has shown no signs of giving way to this point.

To connect the motor to the turnout, a supplied, pre-formed piece of .025" music wire is dropped through a 1/16" hole drilled 3/8" from the

1/16th" hole you drilled in the throw bar. The Rotor Motor is then slipped over the wire from beneath so that the wire passes through the hollow worm shaft. The motor is fastened down with the supplied wood screw. The you set the points in the center, making sure the motor is centered in its throw (it's shipped that way), tape the wire and throw bar down with a piece of electrical tape, and bend the lower end of the wire through the slot in the side of the shaft. The instructions supplied, as well as good pictures on their web site, will answer any questions you may have on this procedure.

Its control scheme requires only two wires to the machine - one from the power supply, one from an spdt toggle switch. The scheme I used was slightly different from what the manufacturer suggested. I wired a diode to each of the outside terminals of the toggle, with each diode pointing in opposite directions. Tied the ends of the diodes together, and ran a wire from those diodes to the Rotor Motor. I used an old Lionel 90-watt transformer to supply a 5.5v AC current, with one side going to the motor, and the other side to the center terminal of the panel toggle switch. This supplies the required DC to the Rotor Motor, which reverses polarity depending on which way the panel switch is thrown. Thus the toggle handle serves to indicate switch posaition.

In operation the unit is reasonably quiet, but suffers slightly from a bit of noise going in one direction I haven't analyzed it yet, but it might be amenable to some grease on the outer end of the worm shaft, where it may be rubbing against the frame.

The frame deserves some mention here. It appears to be machined out of a solid block of a type of very hard resin material. The motor is mounted to it with an epoxy-type substance. Very sturdy.

Conclusion: This is a quality product, at a reasonable price. It functions well, and appears to be reliable. The points are held solidly in place, while not so strongly as to put too much pressure on the stock rails. I plan on ordering many more.

Reply to
Gary M. Collins
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The difference between a stall type motor system and a shutoff system is often just the voltage that is used. The stall system depends upon a sudden high resistance to movement at the limit of travel and just sits there pushing against that resistance until you decide to move it the other way. Worm gear systems usually end up not providing a lot of resistance to the motor relative to the torque that it is applying to the points but you can probably drop the voltage via a resistor and get good operation that way. I will note that the shutoff system is a better system for providing a low speed transfer of the points with widely varying voltages and so forth. You can even set the shutoff system to move with the same kind of voltage as the stall type and have the best of both worlds. My bets are that the motors will run on less than 1V and make the motion nice and slow.

-- There are more Democrats on the Calif. Special Election than Republicans! Go count if you don't believe me! Bob May

Reply to
Bob May

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