The controller switches are designed to handle currents up to a 1000 A.

The switch arm is made of 12mm square copper bar and the contacts are made of round copper bar, 10mm in diameter.

The copper nuts and bolts are M10.

The switch base boards are made of 15 mm plywood with inserts made of 5 mm P1 SRBP bakelite sheet. The inserts are used where required to isolate for high temperatures.

The layout of the switch is shown in the photo below:

For dimensions, open this file.

The Copper Cross Bar hinges around a centre pin (50 mm x 4mm screw). The hole in the centre of the cross bar size is 8mm in diameter to allow for sufficient tolerance. (wear and tear of copper contacts). Two solenoid arms are attached to the cross bar via hinges (30mm x 4mm screws). These arms hinges with the solenoid plungers by means of electrically isolated pins. (30mm x 4mm screws). The construction of the switch is shown in the following pictures:

A fuse is provided in each switch. See picture above. The fuse is made of 7 strands of normal home electric wire size 4 square mm.

Two springs are used to keep the switch in a stable condition each time a solenoid has been activated (for 100ms). The detail of the springs is shown in “How to make the Springs” as described in the Springs Chapter (see site menu ). For the two springs use 22 SWG. (1mm diameter spring wire).

The solenoids are described in the next menu item “Solenoids”