David Wrigley's Microwave Website, Manchester, England

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Waveguide switch operator

After searching for a Ledex solenoid operated WG switch without luck, I decided to convert a manual switch I had to electrical operation.
This WG Switch works from a car door opener. This is a motorized linear actuator working from 12 volts with quite a good output force. After some discussion with Gary Peach G7SLL (a retired professional microwave engineer), it was realized that the big problem isn't moving the switch, it's stopping it without damage to the stops. The system adopted was to incorporate a cam with two microswitches which at the appropriate moment switch off the motor and apply a low resistance across the motor terminals thus providing some braking torque as the stops are approched. The final location is easily accomplished by means fo the built-in detent. There were some initial problems of cam adjustment and more seriously later when a securing bolt fell out, but apart from these everything went well and according to plan. (The bolt falling out caused the motor to operate in a stall state for a long time and not surprizingly it burnt out. Corrective action - make sure all bolts are tightened and important ones locked)
A photo of the completed assy:

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Last updated 2000 December 11