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Permalink Reply by Bob Simmons 29 minutes ago

I assume you're talking about the mag switches for ignition A and ignition B going to the electronic module, essentially P-lead switches. But I'm a bit confused by 'conventional keyed ignition'. Do you mean a RIGHT-LEFT-BOTH-START switch, or are you planning individual left and right toggle switches, with a separate momentary starter switch?

A standard aircraft  RIGHT-LEFT-BOTH-START switch should already be spec'd for what you need.

Individual left and right toggle switches don't have to be AC rated, but they're usually rated for both AC and DC. All they're doing is switching ground on and off to the electronic module. No special requirements for voltage, as long as it's at least 12 volts. But 250 volts certainly wouldn't hurt. And, as I said, it'll probably be rated for both anyway.

It's similar for a momentary starter switch. The starter switch itself does not spin the starter. It just sends a signal to trigger that action to happen elsewhere. In a typical application, that's the solenoid or starter contactor, but on the 914 it's the starter relay. The starter relay is what actually pulls the big current, so the starter switch itself does not have any major voltage or current requirements. 2 amps at 12 volts DC would be fine, but it helps to go a little over on specs, just to be on the safe side. The 914 install manual has some good diagrams for all this.

This might also help:

http://www.aeroelectric.com/articles/MagnetoSwitchOptions.pdf

This also has a couple of suggested part numbers for mil spec toggle switches if you want to go that route. I prefer mil spec for critical circuits if cost allows.

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