how to do i wire one P mag?

[david.perl]

Hi and happy new year

im laying some wires and will be using one P mag, one standard mag, a VPX and a standard keyed switch.

How do i wire the keyed switch to the mags and do i need a switch in the 12 volt wire that goes to the P mag so i can isolate this for testing?

ive searched around and read the bob Knuckles stuff, looked at the P mag site but an still not clear.

thanks in advance

David

 

[penguin]

P-mag manual page 4, terminal 4 goes to the ignition switch - don't forget to remove the jumper, its good practice to ground the mag switch at the P-mag ground (for the mag the screen is typically used as the earth).
Yes, +12v to terminal 5 will need to be switched if you want to test the on-board generator occasionally. It also needs to be switched off the master switch otherwise the P-mag will be live all the time and draining the battery. If the VPX allows that line to be switched off then you could switch it though - but most builders use either a 5A switch breaker or Bob Nuckolls' method - its on aeroelectric somewhere, uses a DPDT switch.
To make the engine independent of the electrical system (after start-up) use a VPX independent method.
You could also consider laying in a 'tack' wire to your engine monitor as it will provide a tacho input whether the P-mag is producing sparks or not.

Pete