The lurgy struck the group leader this week, so class was cancelled. However, part of the session would have been to review a prototype point motor made by Stephen (and cadge some 8BA nuts to finish it off).
Stephen had been investigating the use of miniature servos for point motors on his Gn15 line and Geoff had supplied two documents produced by MERG (Model Electronic Railway Group). One used the servos electronic positioning, and the other used just the motor and gearbox. Whilst both were tested, the latter was thought to be a potential replacement unit for the solenoid point motors on Worton Court.
The supplied drilling template was redrawn to suit the servos and micro switches obtained from eBay and Bitsbox respectively. A unit was made up on a base of 3mm aluminium, left over from a sample cladding panel, but lacked a few 8BA nuts. As Geoff's component shop wasn't available, a visit to Laurence's garage was required and the project was completed. However, it failed to work and worries about the redrawing work loomed - could the micro switches be cancelling each other? Back home, Stephen checked everything and noted that two wires were incorrectly positioned and the matter was resolved. The unit now worked!
Even running on 3v rather than the usual r/c 5v, they are not silent, but it will be interesting to see what it works like in-situ. Maybe next week?
Thin piano wire will be attached to the end of the servo horn and go up into the point tie bar. Stephen uses Peco points, so the frogs are not an issue, but the live frogs on WC will require an additional micro switch to change the polarity. It should be possible to piggy-back one onto one of the units above.
PS After re-reading the MERG article, 1.5v is suggested as a supply for a single motor. Testing confirmed this produced a nice, slow movement, even driving two motors. Cheap 1.5v supplies are available via eBay, which obviates the use of batteries.
