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  #31  
Old 02-02-2021, 07:38 AM
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rockitdoc rockitdoc is offline
 
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I think I finally get it. Tell me, if not.

Ignition switch to L cuts ALL power to R Pmag. A loss of rpm SHOULD occur and this checks to see if engine will run on one Pmag.

Separate toggle switches for each pmag only turn off ship’s alternator power to pmags and If no loss of rpm occurs, checks if internal alternator in each pmag is working.

Right?
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Emp Completed 11-12-20
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  #32  
Old 02-02-2021, 07:45 AM
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Quote:
Originally Posted by rockitdoc View Post
I think I finally get it. Tell me, if not.

Ignition switch to L cuts ALL power to R Pmag. A loss of rpm SHOULD occur and this checks to see if engine will run on one Pmag.

Separate toggle switches for each pmag only turn off ship’s alternator power to pmags and If no loss of rpm occurs, checks if internal alternator in each pmag is working.

Right?
Nope.

Ignition switch (historically called P-Lead) just turns off the spark for that particular PMag.

The test switch (or pulling the breaker) disconnects ships power at which point the PMag's onboard generator should continue providing spark. If it stumbles, your PMag generator has failed and you have a no-go.

The PMag's onboard generator keeps the spark going similar to a traditional mag. It's wired to ship's power for backup. The only way to test whether the generator is generating is to remove ship's power.

To re-iterate the manual, the generators only work above 900rpm. Below 900rpm the PMags are always on ship's power.
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Last edited by bkervaski : 02-02-2021 at 07:50 AM.
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  #33  
Old 02-02-2021, 08:26 AM
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Quote:
Originally Posted by bkervaski View Post
Nope.

Ignition switch (historically called P-Lead) just turns off the spark for that particular PMag.
That's what I thought I said. When this switch is turned to L (left), that pmag is on and running the engine. The R (right) pmag is off, including it's internal alternator. The rpms should drop a bit, indicating that the R Pmag was turned off and the engine will continue on one pmag.

Quote:
Originally Posted by bkervaski View Post
The test switch (or pulling the breaker) disconnects ships power at which point the PMag's onboard generator should continue providing spark. If it stumbles, your PMag generator has failed and you have a no-go.
The separate switch (or breaker, if a separate switch is not fitted) is used to test the internal alternator of each pmag. The ignition switch can't do this since it cuts ALL power to the pmag.

Makes sense, now.

I didn't realize the ignition switch cut all power to the pmag. I thought the internal alternator in the pmag would cut in when the ignition switch was switched to L or R. That's why I thought the extra two switches were redundant. Just trying to eliminate switches on my panel if not needed. Two more switches needed.

Thanks everyone. This helped a lot.
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  #34  
Old 02-02-2021, 08:54 AM
Nova RV Nova RV is offline
 
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Quote:
Originally Posted by rockitdoc View Post
That's what I thought I said. When this switch is turned to L (left), that pmag is on and running the engine. The R (right) pmag is off, including it's internal alternator. The rpms should drop a bit, indicating that the R Pmag was turned off and the engine will continue on one pmag.



The separate switch (or breaker, if a separate switch is not fitted) is used to test the internal alternator of each pmag. The ignition switch can't do this since it cuts ALL power to the pmag.

Makes sense, now.

I didn't realize the ignition switch cut all power to the pmag. I thought the internal alternator in the pmag would cut in when the ignition switch was switched to L or R. That's why I thought the extra two switches were redundant. Just trying to eliminate switches on my panel if not needed. Two more switches needed.

Thanks everyone. This helped a lot.
Almost there- the L switch grounds the right P-Mag preventing spark only, the ship's power and internal alternator on the right mag are still functional. The only way to remove ships power from a P-Mag is via the toggle switch or CB whichever you have. The only way to stop an internal alternator on a P-Mag is to go below 900 RPM. Remember it this way - key switch only stops the spark, toggle or CB prevents power to the P-Mag and below 900RPM is the only way to stop an internal alternator.
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  #35  
Old 02-02-2021, 01:37 PM
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OK, I just spoke to the Emag folks about the P Model and switches.

Here's what they said (which is probably what everyone here has been saying, but I just wasn't getting it):

Runup at 1800rpm
Turn keyed ignition (kill) switch from the Both position to Right mag position. Engine is now running on just the Right mag. (This proves it can)
While the kill switch is still set on the Right mag, flip the switch, push the button or pull the breaker that turns power off to the Right mag.
If the engine keeps running, it means the internal alternator in Right mag is keeping things going. If the engine dies, internal alternator needs help.

Same process for Left mag.

Now, I get it.
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  #36  
Old 02-05-2021, 07:28 AM
Ferdara Ferdara is offline
 
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This is my P-Mag Set up, flying with it for 160 hrs+ love it. Easy to check all in one location. Durning Run up. I (pull and lift up) both P-Mag S/W's to insure NO Drop in RPM. (This cuts the ships power to both P-Mags) The P-Mags generators check complete. Then I do the normal ignition check turn one off (Pull and move down OFF) look for a RPM drop repeat on then the other side. All in one place and ez. Switches from Stein Air and installed by Stein Air. Sept2020
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  #37  
Old 02-05-2021, 07:47 AM
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Quote:
Originally Posted by Ferdara View Post
This is my P-Mag Set up, flying with it for 160 hrs+ love it. Easy to check all in one location. Durning Run up. I (pull and lift up) both P-Mag S/W's to insure NO Drop in RPM. (This cuts the ships power to both P-Mags) The P-Mags generators check complete. Then I do the normal ignition check turn one off (Pull and move down OFF) look for a RPM drop repeat on then the other side. All in one place and ez. Switches from Stein Air and installed by Stein Air. Sept2020
I like it! PMag internal alt test on up movement, PMag operation with ship power on down movement. Clever. So, when you get ready to go after runup, you put both switches in the On position.

It also appears you have your taxi and landing lights on one switch. Center for taxi, up for landing?

Does the red switch turn on the avionics?
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Begun 07-23-20
Emp Completed 11-12-20
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QB Wings delayed until ?
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  #38  
Old 02-05-2021, 08:34 AM
Ferdara Ferdara is offline
 
Join Date: Oct 2018
Location: Lafayette LA
Posts: 39
Default P-Mags FlyLED

P-Mags (every movement of the switch requires you to pull 1st, makes it almost impossible to accidentally switch off) Off is down, Hot or ON/Run is in the Center, Up is ship/aircraft power OFF. So center is P-Mag on normal with aircraft power. Yes light Off Taxi & Taxi/Landing, I used FlyLED in the wing tip, they are great! With the Taxi or Taxi/Landing ON(When the strobe are off they light up at 30% power (steady) to light up the edge of the taxi way. (Side Lighting) They were fun to built too! #PricedRight #FlyLED #Pmag Getting ready to pull the trigger on a QuickBuild RV14A. You will see more of me.... Red Switch turn on the lithium back up battery, powers up the G3x's and more.

Quote:
Originally Posted by rockitdoc View Post
I like it! PMag internal alt test on up movement, PMag operation with ship power on down movement. Clever. So, when you get ready to go after runup, you put both switches in the On position.

It also appears you have your taxi and landing lights on one switch. Center for taxi, up for landing?

Does the red switch turn on the avionics?
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Last edited by Ferdara : 02-05-2021 at 05:57 PM.
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