Van's Air Force
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PMag via main switch or not
- Thread starter Tomas J
- Start date
N890GF
Active Member
PMAG 3-way switch OFF-ON-(TEST)
I have my PMAGs wired to receive power with main switch on, with the PMAG switches in the "Off" position. the ignition "On" position maintains 12v, but un-kills the PMAGs. then the Test position removes 12v but keeps the ignition un-killed.
I've attached my wiring diagram to show switch positions to show how things are connected. The "Test" position is a momentary position and the switch will return to center.
I have my PMAGs wired to receive power with main switch on, with the PMAG switches in the "Off" position. the ignition "On" position maintains 12v, but un-kills the PMAGs. then the Test position removes 12v but keeps the ignition un-killed.
I've attached my wiring diagram to show switch positions to show how things are connected. The "Test" position is a momentary position and the switch will return to center.
If you apply power while the mag is grounded - or in the "off" position, then you put the pmag into "setup mode". This does not seem to cause a problem now, but did with older software versions.
Lots of threads on this topic which seems to come up weekly. Here's a good one:
https://vansairforce.net/community/showthread.php?t=174198
Lots of threads on this topic which seems to come up weekly. Here's a good one:
https://vansairforce.net/community/showthread.php?t=174198
Rick_A
Well Known Member
Southern Pete
Well Known Member
If before the main switch your battery will be flat before too long. The P-mags will be always powered up and will flatten the battery. Once the engine is running the P-mags will be self-sustaining so no danger from a broken/disconnected power wire. Yes, RTFM!!
Desert Rat
Well Known Member
Mine are powered up with the master switch. Not really sure how you would power them before that point unless you're talking about some kind of separate dedicated on off switch running straight from the battery, which could really be a recipe for disaster in a variety of ways.
It's in the installation instructions to do it that way. Here's a cut and paste from page 26 of the install manual:
Notes:
1. Battery power to ignition should switch ON with main bus.
2. “P” models - Do not switch 12/24 V supply OFF/ON except when testing the internal alternator.
MAIN BUS
3. Use p-lead to stop the ignition/engine, not the 12 V supply.
4. Idle current draw (not firing) is approx. 20ma, while max current draw (firing at max rpm) is approx 0.25 amps 5. When installing two (2) E-MAGs, use a separate Circuit Breaker and separate Test Switch for each unit.
It's in the installation instructions to do it that way. Here's a cut and paste from page 26 of the install manual:
Notes:
1. Battery power to ignition should switch ON with main bus.
2. “P” models - Do not switch 12/24 V supply OFF/ON except when testing the internal alternator.
MAIN BUS
3. Use p-lead to stop the ignition/engine, not the 12 V supply.
4. Idle current draw (not firing) is approx. 20ma, while max current draw (firing at max rpm) is approx 0.25 amps 5. When installing two (2) E-MAGs, use a separate Circuit Breaker and separate Test Switch for each unit.
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Tomas J
Active Member
Thanks guys! I have it installed after the main switch but came to discuss it with a friend and thought it might be interesting to expand the discussion. What none of us thought about was the fact that they draw power even in non-active mode, so they must be behind a main switch. The discussion is dead!
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