PMag issue

[eddieseve]

Originally Posted by Bavafa

Here is how I have setup mine,

The power source to PMAG goes thru a toggle (SPDT) switch with an inline fuse connected to this power line. The toggle switch closes the circuit either to the PMAG or an LED warning light, this is that if I accidently leave it in the off position to the PMAG, the warning light is lit.

At the run up area, I switch the PMAG power off and I do my normal PMAG test, also periodically check it with a real low RPM to test the generator portion of the PMAG. If the fuse is burnt, I will know it since the LED wouldn?t light up.

Many ways to skin the potato

I like you LED idea, I think I might steal that :-)

Cheers

[KRviator]

If you have an EMS with a couple of spare inputs, you can do what I did: run two of your spare inputs to the P-Mag's "ships power" input, so you can be assured you have power to the actual ignition, rather than "should have" based on a switch position.

I used DPDT switches for ignition, with the "off" position opening the Pmag ignition circuit, but also grounding an input on the Dynon, so I get a caution message and red light on the screen for that, but the Dynon also measures the voltage to the PMag and will alarm if it goes below a certain voltage.

What I've found through another VAF'er with this arrangement is that if you have ships power off but the engine is running above the self-sustaining speed for the P-mags is that the Dynon will then measure the PMag's internal alternator voltage.

This could give you early warning of a possible fault if you fly with ships power off to the PMag and the internal alternator fails you'll get the alarm, restore ships power and then know your ignition is US before the next flight, rather than finding out during the runup next time.

[moll780]

I have the tyco's for power and breakers and the standard ignition for starting and fouled plug testing.

Originally Posted by eddieseve

Those switches only provide power to my PMags, I have a standard ACS ignition switch that handles grounding, ungrounding my Mags, plus engine start.

Cheers

[eddieseve]

Originally Posted by KRviator

If you have an EMS with a couple of spare inputs, you can do what I did: run two of your spare inputs to the P-Mag's "ships power" input, so you can be assured you have power to the actual ignition, rather than "should have" based on a switch position.

I used DPDT switches for ignition, with the "off" position opening the Pmag ignition circuit, but also grounding an input on the Dynon, so I get a caution message and red light on the screen for that, but the Dynon also measures the voltage to the PMag and will alarm if it goes below a certain voltage.

What I've found through another VAF'er with this arrangement is that if you have ships power off but the engine is running above the self-sustaining speed for the P-mags is that the Dynon will then measure the PMag's internal alternator voltage.

This could give you early warning of a possible fault if you fly with ships power off to the PMag and the internal alternator fails you'll get the alarm, restore ships power and then know your ignition is US before the next flight, rather than finding out during the runup next time.

Could you share what inputs you used for this?

What did you configure to have displayed on the Dynon screen?

Cheers

[GalinHdz]

Originally Posted by KRviator

If you have an EMS with a couple of spare inputs, you can do what I did: run two of your spare inputs to the P-Mag's "ships power" input, so you can be assured you have power to the actual ignition, rather than "should have" based on a switch position.

I used DPDT switches for ignition, with the "off" position opening the Pmag ignition circuit, but also grounding an input on the Dynon, so I get a caution message and red light on the screen for that, but the Dynon also measures the voltage to the PMag and will alarm if it goes below a certain voltage.

What I've found through another VAF'er with this arrangement is that if you have ships power off but the engine is running above the self-sustaining speed for the P-mags is that the Dynon will then measure the PMag's internal alternator voltage.

This could give you early warning of a possible fault if you fly with ships power off to the PMag and the internal alternator fails you'll get the alarm, restore ships power and then know your ignition is US before the next flight, rather than finding out during the runup next time.

That is the setup I have with my 2 P-Mags and the DYNON SkyView EMS. It monitors the voltage at the actual P-Mag not at some switch. I used EMS pins D37-20 & D37-21, which I had available. I think I set it up as a contact to displays green if above 4.5v or red, with an audible alarm, if below 4.5v but would have to find the actual configuration if you need it. You can see the status indications for each P-Mag (LMAGST / RMAGST) in this photo:



You can replace the "status indication lights" with color coded voltage numbers if you want more detailed information. And yes, if you have ships power off but the engine is running above the self-sustaining speed for the P-Mags the DYNON measures the PMag's internal alternator voltage.

It is GREAT.

[akarmy]

Ok GalinHdz, now that is a nice setup. Where were you when I was wiring up my plane. Now if I just had the urge to dive back into the panel and pull some wires I'd be all over this. Maybe at the first condition inspection...

[akarmy]

Originally Posted by Bavafa

Andy,
Where did you find the slow blow fuse? All I have seen are 5A x 250V and none for the 14v.

Yep Same ones Bill listed.

http://www.mouser.com/ProductDetail/...87yhfudQ%3d%3d

and just so we are all clear. Every time this subject comes up the advise is to put breakers in. I'm not some renegade, the manual from E-Mag air does say you can use Slow-Blow fuses and that's what I did.

As to how I wired them, I used two 3-position switchs. Down is off (grounded) like a normal mag, middle is ship power on to the p-mags (ungrounded), momentary spring loaded up is NO ship's power to P-mag so you can test the internal generator. This works just fine and I have had no problems with them thus far. These switches get their power via the slow-blow fuses from the main buss behind the master. So it's master on, then flip both switches up to the middle and start. If you turn off the master the p-mags are on internal generator once they start anyways. I'm not suggesting you wire yours this way, just explaining what I did.

[KRviator]

Originally Posted by eddieseve

Could you share what inputs you used for this?

What did you configure to have displayed on the Dynon screen?

Cheers

For my PMag power I used Pins 4 & 23 IIRC. These two were spare but their wire stripe colour matched the tach input lines.

Configure them as contact inputs, with Range 1 being Red 0.0-4.5V and Range 2 being Green 4.5-5.0V. These input pins are 0-5V inputs, but are capable of sinking 15V without damage, though anything above 5V is simply read as 5.0V, hence the highish (4.5V) cutoff point.

IF you want to measure the actual voltage in real time, rather than ON/OFF as I do, you will need to use Pin 1 & 2, as I think they're the only ones that will do measurements above 5V - but that then limits your capacity to measure battery or avionics bus voltages...

For my two ignition switches, they are DPDT switches, one side actually switches the PMag circuit, the other grounds the Dynon's sensor line. I used Range 1, Red, 0.0-2.5V & Range 2, Green, 2.5-5.0V. I can't remember what pins I used there, but any GP input should do.

Ranges 3,4, & 5 are unused on both, as I can't see the point in measuring an in-between voltage in flight. IT's either enough, or it's not.

Then all you have to is configure where you want them on your screen, and if you want text associated with them, alarm as latching or self-clearing, etc...Mine are bottom-right in the 50% screen and show "OFF" if there's a problem and "OK" if, well, everything is OK!

[eddieseve]

Thanks to both of you for your Dynon setup information, that has given me lots to ponder, like Andy I am wondering if I want to dive under the panel again, but what you guys have done is fabulous.

Cheers

[billdianne]

Originally Posted by akarmy

Yep Same ones Bill listed.

http://www.mouser.com/ProductDetail/...87yhfudQ%3d%3d

and just so we are all clear. Every time this subject comes up the advise is to put breakers in. I'm not some renegade, the manual from E-Mag air does say you can use Slow-Blow fuses and that's what I did.

As to how I wired them, I used two 3-position switchs. Down is off (grounded) like a normal mag, middle is ship power on to the p-mags (ungrounded), momentary spring loaded up is NO ship's power to P-mag so you can test the internal generator. This works just fine and I have had no problems with them thus far. These switches get their power via the slow-blow fuses from the main buss behind the master. So it's master on, then flip both switches up to the middle and start. If you turn off the master the p-mags are on internal generator once they start anyways. I'm not suggesting you wire yours this way, just explaining what I did.

I did the same as Andy. I liked the idea that the whole circuit is protected
all the way back to the fuse block by the slow-blow fuses. It seemed to me with the breaker the wire from the breaker to the main bus is unprotected. At least that's the way my mind saw it(see avatar).