"GENERAL NOTES:
THE WHOLE PURPOSE IN PRODUCING THIS ITEM WAS TO THWART THE NEED FOR CONTACTORS, MOST OF WHICH REQUIRE UPWARDS OF 1 AMPERE TO REMAIN CONNECTED. 4 CONTACTORS TO STAY CONNECTED FOR THE LENGTH OF THE FLIGHT WAS EXCESSIVE IN VIEW OF EXPECTED NEEDS, SO A MECHANICAL ALT-ERNATIVE WAS DEVISED.
ONE EXAMPLE IS THE MASTER SWITCH WHICH IS A RACING CAR CUTOFF SWITCH OPERATED BY A REPLACEMENT ‘KEY’ WHICH PENETRATES THE INSTRUMENT PANEL FOR 11 INCHES AND IS INTERNAL PANEL-MOUNTED.
BELOW IS THE OTHER EXAMPLE. FOLLOWING THE SUGGESTION OF BOB NUCKOLLS, A SLIDING ELEMENT PROVIDES ON/OFF CONTACT WITH TWO BRASS POSTS. THE RESULT IS ABOUT EQUAL IN CONTACT RESISTANCE TO THE USUAL COMMERCIAL CONTACTOR. DIMENSIONS ARE NOMINAL AND DEPEND ON EXPECTED LOADS AND DURATION. IN MY CASE, THE LINES ARE ERIC JONES CCA#4 CABLE FROM BATTERY TO FIREWALL FORWARD POSTS."
I would like to beg a boon to give Bob Nuckolls some credit for the initial design? I complained to him about high running current in contactors and he sketched the basic idea, so it’s really his baby I think. I have built several of these before settling on one model, but some have 1/4inch posts and some 5/16"
