I have an Aircraft Spruce ignition switch. It came with a small wire with a diode made in it with instructions about installing it between a ground and the switch terminal on the start relay. What is the purpose of this wire and diode?
Thanks in advance!
When the solenoid coil field collapses it generates a reverse voltage (flyback) that would arc across the switch contacts as they open and damage them. The diode shorts this voltage and turns it to heat within the diode's resistance rather thah spark heat at the switch contacts. It's a flyback suppression diode. Diode's cathode to positive terminal of solenoid.
When the service bulletin came out and I changed my ignition switch, I took the old one apart. You can see a little arcing on the leftmost contact. The diode will prevent that.
To add tothe previous guidance, Many rv builder put a diode directly on the starter solenoid. If you already have one properly installed there, you do mot need another at the switch.
Larry
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N64LR - RV-6A / IO-320, Flying as of 8/2015
N11LR - RV-10, Flying as of 12/2019
Thanks for the info. Mine is hooked up to the start relay per the instructions that came with the switch. The directions just did not tell you what it does.
ACS ignition switch question
Linear Mode
