Wafer Switch

This is a progressive shorting wafer switch that is capable of 5KV dielectric strength. Finding progressive shorting switches is getting difficult and finding one that actually has the progressive shorting feature that you may need is even more difficult.
We decided to solve this problem by building our own switch. We use phospor bronze for the contactor wafer and nickel-silver for the contactors themselves. This is the same material that we use in our roller inductor and capacitor contactors and it works very well.

Each wafer switch comes with a positive detent device for solid "clicks" when switching positions. this is done with with a spring loaded ball bearing that rides on a resistance wheel built into the switch. The resistance wheel gives the switch a smooth and firm feel when switching between terminals.

The switch pictured above is a 1 pole 2 terminal switch. The pole is switched "into" the terminals in a progressive fashion. In position #1 none of the terminals are activated. In position #2 the pole and terminal #1 are shorted together. In position #3 the pole, terminal #1 and terminal #2 are shorted together.

This switch is used in our symmetric tuner for switching in additional fixed capacitance when required to obtain a perfect match.

Switch installation

This picture shows how the switch is mounted in the tuner housing. The switch is used to bring additional fixed capacitance in parallel with the variable loading capacitor. The center axle of the switch is "hot", thus the switch must be isolated from the chassis. You can see the shaft isolator in this picture.

Additional Fixed Caps

This picture illustrates how the fixed capacitance is tied into the switch. The caps are floated above the switch on solid copper wires. This was done to reduce lead length and the solid wire provides plenty of strength to hold the capacitors in place.