The boards were designed using AUTOTRAX CAD & drawn on the board by a Roland - Cammscribe CS20 then etched in a bowl on the kitchen table !
The Driver uses IHF540 FETs rated at 25A / 80v. Each board is isolated by a 4N28 opto coupler. Once assebled and tested, i installed them along side their respective switch.
With a 5 m/second 50 volt pulse, they will run at 20 steps per second without a problem. At 22sps, they skip. I have installed 1.2A poly switches in line with the uniselector coil to fail the switch if it becomes perminently energised.
These switches are about to go under microprocessor controll :) The plan to date is to use one programmable processor (Motorola HC05) to control all eight uniselectors.
Operator....
