RVG8tor

RVG8tor

Well Known Member
I am trying to help someone who is installing a Pmag on the left side and keeping traditional mag on the right. Both his mag where impulse versions, he says. Issue we have is when he selects left mag the P-lead wire to the Pmag should go to ground but it opens the circuit.

Traditional mags P-leads typically are grounded when switch is off, P-mag needs P-lead to be ungrounded when switch is off and ground when the P-mag is selected.

I did not use a keyed ignition and don't know how the ca. Be wired to make this work. Instructions are not clear on this

Thanks for any help.
Call or post
360 nine five one 6503
 
Pmag works exactly like a regular mag. The P lead grounds to turn it off. If both regular mags were impulse (both "hot" when cranking), then wire it up exactly the same as the old mag.
 
Diagram

Toobuilder said:
Pmag works exactly like a regular mag. The P lead grounds to turn it off. If both regular mags were impulse (both "hot" when cranking), then wire it up exactly the same as the old mag.
Click to expand...

Shows Plead to ground when switch closed, plugs are hot. Switch off opens circuit to ground which stops current to plugs
 
Look at the p-mag manual (quoted below). The p-lead (pin 4) goes to ground to turn off the ignition. It's pin 5 that goes to 12V to turn on the ignition. That's the main difference. You need to provide power to the p-mag separate from the p-lead switch which is simply telling it to make spark or not.

So the question is, on the keyswitch being used, are the jumpers already pulled as referenced in the p-mag manual? If so then both left and right will be un-grounded during cranking and everything should be fine to hookup to the p-mag. If not, then pull the jumper for the side you are installing the p-mag on.

Maybe put an ohm meter on the switch to verify what's happening with the grounds when the switch is in the various positions to clear up the confusion.

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pin 4 connects to your ignition ON/OFF p-lead switch (to ground) using 20 gauge wire or larger.

Note 1: If you are replacing a magneto, your old P-Lead can serve this purpose, and may already be wired to a suitable switch. Take care that magneto p-lead wire is shielded, and the shielded braid is a potential (unintentional) short to ground. Keep it clear of connections and terminals.

Note 2: Non-starting magnetos require a mechanism to prevent them from firing during start-up. Keyed ignition switches have a jumper on the back that serves this purpose. When installing an E-MAG in place of a non-starting magneto that was controlled by such a switch, make sure you remove this jumper. You do NOT want a start-up block on any circuit controlling your E- MAG(s).

pin 5 connects to your main 12 volt aircraft buss, routed through a dedicated 3 amp switchable circuit breaker (not provided) using 18 gauge wire. If using a fuse (instead of breaker), use a slow-blow type. The switch function is needed to test the (P model) internal alternator during ground run up ? see Operating Notes.
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Just flew with P Mag for first time today... wired as Andy discussed.
Worked fine.
But... cylinder #3 is even hotter now. DARN.
Wonder if we could get a group buy on #3 cyl. replacements....
Gonna need them.
 
Call cell please

akarmy said:
Look at the p-mag manual (quoted below). The p-lead (pin 4) goes to ground to turn off the ignition. It's pin 5 that goes to 12V to turn on the ignition. That's the main difference. You need to provide power to the p-mag separate from the p-lead switch which is simply telling it to make spark or not.

So the question is, on the keyswitch being used, are the jumpers already pulled as referenced in the p-mag manual? If so then both left and right will be un-grounded during cranking and everything should be fine to hookup to the p-mag. If not, then pull the jumper for the side you are installing the p-mag on.

Maybe put an ohm meter on the switch to verify what's happening with the grounds when the switch is in the various positions to clear up the confusion.

--
pin 4 connects to your ignition ON/OFF p-lead switch (to ground) using 20 gauge wire or larger.

Note 1: If you are replacing a magneto, your old P-Lead can serve this purpose, and may already be wired to a suitable switch. Take care that magneto p-lead wire is shielded, and the shielded braid is a potential (unintentional) short to ground. Keep it clear of connections and terminals.

Note 2: Non-starting magnetos require a mechanism to prevent them from firing during start-up. Keyed ignition switches have a jumper on the back that serves this purpose. When installing an E-MAG in place of a non-starting magneto that was controlled by such a switch, make sure you remove this jumper. You do NOT want a start-up block on any circuit controlling your E- MAG(s).

pin 5 connects to your main 12 volt aircraft buss, routed through a dedicated 3 amp switchable circuit breaker (not provided) using 18 gauge wire. If using a fuse (instead of breaker), use a slow-blow type. The switch function is needed to test the (P model) internal alternator during ground run up ? see Operating Notes.
--
Click to expand...


Andy call cell phone it is 360 nine five one 6503 if you can.
 
Make sure you're not confusing the "P lead" with "power".

If you ground terminal 4 (P lead), the engine will quit... Just like a mag.
 
Last edited:
Issue keyed IGN

We have power wire set properly. Nothing was done to IGN switch end of things. No jumpers as plane had two start mags installed. When I test continuity of the P-Mag P- lead it is grounded in OFF, Left , right positions. It works in Both. So the issue seems to be with the IGN switch.

Correction to my previous post. The Pmag is on the right side regular start mad on the left.

Why would plead stay grounded when R selected. I just don understand what the keyed ignition is doing when it moves L/R/Both. I know what it should do.

More help please.
 
Are you testing the switch terminals with the ignition P lead attached? If so, you're likely finding ground through the PMag itself. Remember, this thing does not have any points opening and closing. Verify the switch is working properly without any ignitions hooked to it, then wire the PMag just like you would a magneto.

Remember, when checking the Right mag, the Left is grounded.
 
Problem solved

Turns out the L/R on the switch are reversed so it would not work when R selected. Once we discovered this it all worked well.

Thanks for the help.
 
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