Point actuators
Engine and engine room
A full compliment this week. Laurence continued making his first actuator.
As well as making the basic unit, an extra micro-switch needed to be incorporated to switch the frog polarity. (This could be fitted directly to the point tie-bar, but having it on the actuator was considered a better solution). Doubling-up one of the existing switches was considered first, but then locating it on the base plate and using a double-ended servo horn was chosen. It will be located beneath the left-hand switch.
With the engine now running, and the generator room shell formed, the electric drive for the engine was investigated. A 6v motor with a built-in gearbox was found. Initially tested with a twist of masking tape on the axle, it drew a high current and ran quite hot and noisily. With nothing else available, Geoff located an 'O' ring and turned up a brass pulley. Tested again, the same issued forced a renewed search. A Hornby 12v motor with a nylon worm drive solved the problem.
The spline on the shaft prompted the making of new, nylon 'pulley' for a smaller 'O' ring.
It worked beautifully. Because of the drive-wheel size, it will need to be mounted slightly higher than the floor finish, but it will not be seen. A plasticard plinth was fitted to the floor and holes formed and tapped to fix the engine down.
In positioning the engine in the new room, it was noted that an area where a rack of batteries was supposed to go had been filled in with a wall. Instead of breaking it out, Geoff came up with ' a cunning plan' by suggesting the introduction of a mezzanine over the control panel, which could have a single row of batteries. This was enthusiasticly picked up by Stephen, and between them, a scheme developed, incorporating cast columns, brackets, floor panels, handrails and a ladder.
Previously published drawings and photos
