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jgold4747(at)yahoo.com
Guest

Posted: Sat Sep 22, 2007 7:25 am Post subject: P-mag wiring

There was some discussion on this list while Bob was out of town in August about the pros and cons of his wiring approach for P-mags (Figure Z-33) vs. the "factory" approach.  Bob, any comments on this matter?  (I'm getting very close to needing to make a final decision about this...)

   

       John Goldsmith (RV-7A, serious panel planning starting)

   



  to amazing places on Yahoo! Travel.  [quote][b]

aurbo(at)ak.net
Guest

Posted: Sat Sep 22, 2007 8:18 am Post subject: P-mag wiring

John,

  

 I would be surprised if this response  doesn't get deleted. The last couple I have submitted have not been posted.  But:

  

 Referencing P/E mags I would like to make  a comment.  

 The following comments are my  opinions.

 

The wiring diagrams in Bob's Z  figures don't agree with the way the P/E mag 

folks say to wire their  products.



I think it is likely that some of the problems experienced  with  P/E mags is 

because they were wired wrong.



I suggest that  if your going to use P/E mags wire them like Emagair says and 

follow their  directions.



Mike





 [quote]   ---

ssamps(at)gmail.com
Guest

Posted: Sun Sep 23, 2007 11:09 pm Post subject: P-mag wiring

I have been thinking about P-mag wiring recently since I will also be doing it shortly. My instinct is to follow E-mag's wiring, however it does cause more switches than I really want, to control them.

  

 My thought was this. If you had a 2-50 switch wired so that:

  

 - in the bottom position with the master on, the P-mag was powered, buty the P-lead off.

 - in the middle position (and this is the normal flying position) the power and P-lead is on.

 - in the top, momentary, position the power is cut. (To test the self generation.)

  

 This would appear to overcome what I percieve as e-mag's reservation. They want power on the things before the P-lead is switched on, except for the momentary test of the self generation.

  

 Can anyone see a problem? It appears to me to provide for everything AND the switching occur in the order E-mag want?

  

 Thanks, Steve.



 

 On 22/09/2007, Michael T. Ice <aurbo(at)ak.net (aurbo(at)ak.net)> wrote: [quote]  John,

  

 I would be surprised if this response doesn't get deleted. The last couple I have submitted have not been posted. But:

  

 Referencing P/E mags I would like to make a comment.   

 The following comments are my opinions.

 

The wiring diagrams in Bob's Z figures don't agree with the way the P/E mag 

folks say to wire their products.



I think it is likely that some of the problems experienced with  P/E mags is  

because they were wired wrong.



I suggest that if your going to use P/E mags wire them like Emagair says and 

follow their directions.



Mike





 [quote] ---

klehman(at)albedo.net
Guest

Posted: Mon Sep 24, 2007 4:00 am Post subject: P-mag wiring

Steve

FWIW I consider it good cockpit design to have all non guarded switches 

full up in the normal position.  It may be asking for operator error to 

expect one to discern the middle position especially at night or when 

checking quickly by feel.  So if this works electrically I'd suggest 

adding  guards that force the switch to the center position when closed.

Ken



Steve Sampson wrote:



 	  Quote: 	
		   I have been thinking about P-mag wiring recently since I will also be 

 doing it shortly. My instinct is to follow E-mag's wiring, however it 

 does cause more switches than I really want, to control them.

  

 My thought was this. If you had a 2-50 switch wired so that:

  

 - in the bottom position with the master on, the P-mag was powered, 

 buty the P-lead off.

 - in the middle position (and this is the normal flying position) the 

 power and P-lead is on.

 - in the top, momentary, position the power is cut. (To test the self 

 generation.)

  

 This would appear to overcome what I percieve as e-mag's reservation. 

 They want power on the things before the P-lead is switched on, except 

 for the momentary test of the self generation.

  

 Can anyone see a problem? It appears to me to provide for everything 

 AND the switching occur in the order E-mag want?

  

 Thanks, Steve.

lamphere(at)vabb.com
Guest

Posted: Mon Sep 24, 2007 5:25 am Post subject: P-mag wiring

Steve,

  

 I have a P-Mag and E-mag that I will be using in my Tailwind.  This summer I wired up (90%) my panel and after much consideration did the  following:

  

 E-Mag power supplied by the EBUS -> circuit breaker ->  E-Mag

  

 P-Mag power supplied by the EBUS -> circuit  breaker -> momentary off / normally on SPDT switch (I can get  the number if you need it) -> P-Mag

  

 P leads to both units are connected to a "standard"  key ignition switch with the ground connection to one "mag" removed at the  start position (no need to have this with the E/P-Mags).

  

 Of course with the EBUS alt feed switch "off", power is  supplied to anything on the EBUS when the master switch is on.

  

 That's the way I am proceeding...

  

 Dave

  

  

 [quote]   ---

ssamps(at)gmail.com
Guest

Posted: Mon Sep 24, 2007 6:21 am Post subject: P-mag wiring

Ken, I see your point and would agree normally, but bearing in mind that I was talking about a momentary switch where it only is full up while you hold it there (to cut the power and test the self generation capability) and it then returns to the middle, do you still see that as an objection? I plan to tuck them in under the panel, its a -4, where nothing will fall down on them, but well in line of sight.. Since they are on their own it will not be visually odd. Thanks, Steve. 



 On 24/09/2007, Ken <klehman(at)albedo.net (klehman(at)albedo.net)> wrote: [quote]--> AeroElectric-List message posted by: Ken <klehman(at)albedo.net  (klehman(at)albedo.net)>



Steve

FWIW I consider it good cockpit design to have all non guarded switches

full up in the normal position.  It may be asking for operator error to

expect one to discern the middle position especially at night or when 

checking quickly by feel.  So if this works electrically I'd suggest

adding  guards that force the switch to the center position when closed.

Ken



Steve Sampson wrote:



[quote] I have been thinking about P-mag wiring recently since I will also be 

 doing it shortly. My instinct is to follow E-mag's wiring, however it

 does cause more switches than I really want, to control them.



 My thought was this. If you had a 2-50 switch wired so that: 



 - in the bottom position with the master on, the P-mag was powered,

 buty the P-lead off.

 - in the middle position (and this is the normal flying position) the

 power and P-lead is on. 

 - in the top, momentary, position the power is cut. (To test the self

 generation.)



 This would appear to overcome what I percieve as e-mag's reservation.

 They want power on the things before the P-lead is switched on, except 

 for the momentary test of the self generation.



 Can anyone see a problem? It appears to me to provide for everything

 AND the switching occur in the order E-mag want?



 Thanks, Steve.  [quote][b]

klehman(at)albedo.net
Guest

Posted: Mon Sep 24, 2007 7:02 am Post subject: P-mag wiring

Hi Steve

A momentary up position switch does sound a bit better if you can find 

such a thing but personally I'd still consider such an arrangement to be 

not the best.  I'd pefer a flip up guard or a separate push to test 

button if failure of a separate button would not fail the mag.  Another 

option that appeals to me would be a lift lock switch that acts like a 

two position switch but has to be lifted or pulled to select the third 

position. Those come in spring loaded versions as well but either way I 

like some arrangement that still lets you confirm the normal on position 

by touch alone.   Maybe I'm silly but my experience is that we see what 

we expect to see and sometimes actually touching and applying pressure 

to a switch while checking it reveals that it wasn't where we thought it 

was. Certainly the angle of view of the switch is a factor as well. It 

is often easier to ascertain a switch positon on the far side of the 

cockpit than for the switch directly in front of you. Many pilot errors 

are a direct predictable result of poor cockpit design.

Ken



Steve Sampson wrote:



 	  Quote: 	
		   Ken, I see your point and would agree normally, but bearing in mind 

 that I was talking about a momentary switch where it only is full up 

 while you hold it there (to cut the power and test the self generation 

 capability) and it then returns to the middle, do you still see that 

 as an objection? I plan to tuck them in under the panel, its a -4, 

 where nothing will fall down on them, but well in line of sight.. 

 Since they are on their own it will not be visually odd. Thanks, Steve.



 On 24/09/2007, Ken <klehman(at)albedo.net <mailto:klehman(at)albedo.net>> wrote:



     

     <mailto:klehman(at)albedo.net>>



     Steve

     FWIW I consider it good cockpit design to have all non guarded

     switches

     full up in the normal position.  It may be asking for operator

     error to

     expect one to discern the middle position especially at night or when

     checking quickly by feel.  So if this works electrically I'd suggest

     adding  guards that force the switch to the center position when

     closed.

     Ken



     Steve Sampson wrote:



     > I have been thinking about P-mag wiring recently since I will

     also be

     > doing it shortly. My instinct is to follow E-mag's wiring,

     however it

     > does cause more switches than I really want, to control them.

     >

     > My thought was this. If you had a 2-50 switch wired so that:

     >

     > - in the bottom position with the master on, the P-mag was powered,

     > buty the P-lead off.

     > - in the middle position (and this is the normal flying

     position) the

     > power and P-lead is on.

     > - in the top, momentary, position the power is cut. (To test the

     self

     > generation.)

     >

     > This would appear to overcome what I percieve as e-mag's

     reservation.

     > They want power on the things before the P-lead is switched on,

     except

     > for the momentary test of the self generation.

     >

     > Can anyone see a problem? It appears to me to provide for everything

     > AND the switching occur in the order E-mag want?

     >

     > Thanks, Steve.

nuckolls.bob(at)cox.net
Guest

Posted: Mon Sep 24, 2007 7:03 am Post subject: P-mag wiring

At 09:26 AM 9/24/2007 -0400, you wrote:



 	  Quote: 	
		  Steve,



I have a P-Mag and E-mag that I will be using in my Tailwind. This summer 

I wired up (90%) my panel and after much consideration did the following:



E-Mag power supplied by the EBUS -> circuit breaker -> E-Mag



P-Mag power supplied by the EBUS -> circuit breaker -> momentary off / 

normally on SPDT switch (I can get the number if you need it) -> P-Mag


	


   Electrical items needed for operation of the engine should

   be fed from a battery bus. If you have elctrical system problems

   and need to shut the master OFF, then you don't want the engine

   to stop.



   Bob . . .

ldavis_pe(at)cox.net
Guest

Posted: Mon Sep 24, 2007 12:34 pm Post subject: P-mag Wiring

[img]cid:image001.jpg(at)01C7FEAF.7F99DB70[/img]    

I’m also in the process of wiring up my dual p-mags. Given the concerns on this thread and others I’m not comfortable with the best way to proceed. I’ve generally followed the Z-11 architecture (batt bus, ebus and main bus) and have the dual 2-10 and a 1-3 switches to install the pmag wiring per Fig. Z-33 “Maintenance / Hand Prop Option for E-Mags / PMags”.  

I’m aware that Emagaire recommends a wiring diagram that seems quite different than Fig. Z-33. I must admit I don’t understand all of the issues in wiring the manufacturer’s way vs. that given in Fig. Z-33 and  would sincerely appreciate any help I can get on the single most important wiring in my project.   

Regards,

 Les Davis

image001.jpg

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aurbo(at)ak.net
Guest

Posted: Mon Sep 24, 2007 1:06 pm Post subject: P-mag Wiring

Les, 

Follow the folks that make them and use their wiring system. It is different then the Z-11 & 33 but it's the way Emagair suggests. You can't go wrong using the manufactures wiring diagram. Why do it differently when the Z-11 & 33 schematic offer no advantage. 

Mike ice 

---

lamphere(at)vabb.com
Guest

Posted: Mon Sep 24, 2007 3:11 pm Post subject: P-mag wiring

Bob,



Are you saying that WHILE YOU ARE IN FLIGHT the time it takes to switch off 

master and switch on Ebus (less than 2 seconds - even with shaking hands - 

the switches are next to each other), that the prop will stop before the 

Emag will work??? ... and by the way, I'm using a P-Mag also - I believe 

that will be happy without power as long as the engine is above low idle...



Seems OK to me... what am I missing??



Dave

---

lamphere(at)vabb.com
Guest

Posted: Mon Sep 24, 2007 3:25 pm Post subject: P-mag Wiring

I hate to draw this out - but - according to the installation  manual, page 20, we are only talking about one +13.8vdc lead, a circuit  breaker and a test switch (for a PMag, none required for an EMag) plus the  necessary ground. That said, you will note that the manual schematic shows the  +13.8v dc lead coming from the battery contactor (main bus). IF you ever have to  shut down the main bus (disengage the contactor) and you don't have an alternate  source for EMag power... well, you get the picture....  If you have 2  P-Mags and they are working - no need to be concerned...

  

 It really isn't THAT complicated an issue.

  

 Dave

 [quote]   ---

nuckolls.bob(at)cox.net
Guest

Posted: Mon Sep 24, 2007 5:50 pm Post subject: P-mag wiring

At 07:08 PM 9/24/2007 -0400, you wrote:



 	  Quote: 	
		  

<lamphere(at)vabb.com>



Bob,



Are you saying that WHILE YOU ARE IN FLIGHT the time it takes to switch 

off master and switch on Ebus (less than 2 seconds - even with shaking 

hands - the switches are next to each other), that the prop will stop 

before the Emag will work??? ... and by the way, I'm using a P-Mag also - 

I believe that will be happy without power as long as the engine is above 

low idle...



Seems OK to me... what am I missing??



Dave


	


   If you have smoke in the cockpit that "smells electrical" then

   there's nothing to tell you that the smoke is NOT coming from an

   e-bus powered accessory. The prudent thing is to remove ALL practical

   power from the ship's systems . . . practical meaning that

   electrically dependent engines should NOT be deprived of energy

   when everything else is.



   Once order is restored in the cockpit, the pilot is certainly

   free to begin "troubleshooting". Turning things on one at

   a time, etc. I strongly discourage this activity while

   airborne. Get the stuff out of your flight bag (you DO

   have good stuff in your flight bag . . . no?) and get on

   the ground before you start investigating the source of the

   smoke.



   It's not a matter of being able to change configuration by

   repositioning switches. It's a matter of getting ship's wires

   to max cold and getting on the ground without breaking a

   sweat. Therefor the recommendation is that any device the engine

   depends on for operation (hence banned from the list of

   candidates for practical shutdown) should be powered from an

   always hot battery bus.



   Bob . . .

lamphere(at)vabb.com
Guest

Posted: Mon Sep 24, 2007 7:38 pm Post subject: P-mag wiring

This is my very last comment on this matter.



Reading your last email kind of makes me sorry I ever went to the bother to 

incorporate an EBus in my system. I made a mistake thinking it was to insure 

you could continue the flight long enough to safely get on the ground. 

According to this last response, that's not the reason.



I guess could have just stuck with switches for each item and eliminated the 

extra components and complexity (like diode arrays, multiple bus "bars", 

switches, etc.)



Too bad I didn't get involved with this discussion sooner.. like 6 months 

ago...



Maybe it's not too late to redo the panel in a simpler version before 

installation.



Dave



---

nuckolls.bob(at)cox.net
Guest

Posted: Mon Sep 24, 2007 8:12 pm Post subject: P-mag wiring

At 11:38 PM 9/24/2007 -0400, you wrote:



 	  Quote: 	
		  

<lamphere(at)vabb.com>



This is my very last comment on this matter.



Reading your last email kind of makes me sorry I ever went to the bother 

to incorporate an EBus in my system. I made a mistake thinking it was to 

insure you could continue the flight long enough to safely get on the 

ground. According to this last response, that's not the reason.



I guess could have just stuck with switches for each item and eliminated 

the extra components and complexity (like diode arrays, multiple bus 

"bars", switches, etc.)



Too bad I didn't get involved with this discussion sooner.. like 6 months 

ago...



Maybe it's not too late to redo the panel in a simpler version before 

installation.



Dave


	


   I'm sorry that you're disappointed but I'm mystified as

   to why. The architectures offered in the Z-figures and

   the rationale for what equipment items should drive from

   which bus seems pretty straight-forward. You didn't not

   mention which Z-figure you were incorporating. Z-13/8?

   If it makes you feel better, put the emags on what ever

   bus you like . . . it's your airplane. But I'd like to

   understand how we failed to help you understand the functionality

   of all the features within the z-figures. Have you

   read chapter 17?



   The e-bus was crafted to offer a minimum power consumption

   dual power path mode for endurance . . . it has NOTHING to

   do with getting safely on the ground. Getting safely on the

   ground is the responsibility of the pilot knowing exactly what the

   limits are for his/her options. Limits are determined by

   hardware selection, architecture selection and most important,

   preventative maintenance of the battery so that you can

   confidently fly right up to those limits.



   Smoke in the cockpit is rare and unique event that supercedes

   wear-out failures in importance. The e-bus minimizes loads

   for continued flight to airport of intended destination.

   The procedure for dealing with smoke makes no pretenses

   about continued flight. It's time to come down NOW and

   with a minimum of electrical hardware powered up.



   Drop the e-bus if you like. Drop the second alternator

   if you find that too complex. But run your engine goodies

   of the battery bus no matter which architecture you choose.



   Bob . . .

ssamps(at)gmail.com
Guest

Posted: Mon Sep 24, 2007 11:30 pm Post subject: P-mag Wiring

Dave, It is very simple, except Bob's proposed wiring, abuses one preference "by the good folk at EW-magair". E-mag's preference is that the mag is always powered (presumably the firmware initialised) BEFORE the P-lead is opened. They presumably have knowledge of how they wrote the code and the reason why they say this. 

  

 Bob on the other hand has never explained, to my very limited knowledge, how he can ignore this preference, and how it interacts with the code initialisation.. Bob? 

  

 It was for this reason that I asked if anyone could see a problem with a 2-50 type switch which I described before:

  

 - in the bottom position with the master on, the P-mag was powered, but the P-lead off.

 - in the middle position (and this is the normal flying position) the power and P-lead is on.

 - in the top, momentary position, the power is cut. (To test the self generation.) The P-lead remains on.

  

 Operating this way the P-mag would see power once the master is on. It would only loose power from the battery when the engine is running and you switch to the self generation test. P-mag condone that.

  

 The one important assumption I am making with my proposal, is that as you move from the bottom to the midle position, the power cant 'flutter' for an instant, and the P-lead connected, BEFORE the power connection is remade. I presume with these switches the connection is not lost, however briefly? Bob, if you are reading this can you confirm my understanding of how the contacts move in these switvches? 

  

 Thanks, Steve.

 

  



 

 On 25/09/2007, David & Elaine Lamphere <lamphere(at)vabb.com (lamphere(at)vabb.com)> wrote: [quote]  I hate to draw this out - but - according to the installation manual, page 20, we are only talking about one +13.8vdc lead, a circuit breaker and a test switch (for a PMag, none required for an EMag) plus the necessary ground. That said, you will note that the manual schematic shows the +13.8v dc lead coming from the battery contactor (main bus). IF you ever have to shut down the main bus (disengage the contactor) and you don't have an alternate source for EMag power... well, you get the picture....  If you have 2 P-Mags and they are working - no need to be concerned... 

  

 It really isn't THAT complicated an issue.

  

 Dave

 [quote] ---

aurbo(at)ak.net
Guest

Posted: Tue Sep 25, 2007 6:35 am Post subject: P-mag Wiring

Steve,

  

 Your idea seems good to me. But I wonder  why do you want to use the 2-50 switch? Why not just wire the mags the way the  Emagair folks suggest? 

  

  One thing I like about the AeroElectric  idea is the concept of reducing "parts count". More parts equals more possible  trouble. But in this instance either system uses at least 2 switches for each  P-mag, so it is a wash.

  

 I understand the need for the switch to  shut off the power to the P-mag so you can check the internal alternator but why  hide them? If you hide them will you need a warning light to tell you they are  in one position or another? I have been thinking I might use a toggle switch  with an LED light in the end of it. 



  

  The AeroElectric z-33 figure shows the  2-10 switch being hooked up to P-mags using wire colors. I think that it would  be better if the connector plug was numbered on those drawings. The E/P mags  don't have colored wires on them.

  

 I agree, we should hope that Bob and Emag  can get together and come up with a one size fits all, with a reduced parts  count, and doesn't cause damage to the P-mags with and accidental push or flick  of a switch.



  

 I propose until this situation is sorted  out by us, that those of us installing and flying behind these E/P mags follow  the manufacturers wiring diagrams.

  

  I do like Bob's suggestion to wire the  mags to the battery bus.



  

 Mike

 [quote]   ---

nuckolls.bob(at)cox.net
Guest

Posted: Tue Sep 25, 2007 7:18 am Post subject: P-mag Wiring

At 08:27 AM 9/25/2007 +0100, you wrote:



 	  Quote: 	
		  Dave, It is very simple, except Bob's proposed wiring, abuses one 

preference "by the good folk at EW-magair". E-mag's preference is that the 

mag is always powered (presumably the firmware initialised) BEFORE the 

P-lead is opened. They presumably have knowledge of how they wrote the 

code and the reason why they say this.



Bob on the other hand has never explained, to my very limited knowledge, 

how he can ignore this preference, and how it interacts with the code 

initialisation.. Bob?


	




   I've crafted a note to Brad Demet with a goal

   of repairing a demonstrable disconnect in my understanding

   of e-Mag's functionality. I've posted a copy of my

   note to the list.



   Sorry to take so long to climb back into this particular

   'stew pot' . . . I've had too much stuff piled onto my

   plate over the past 6 months. I trust that Brad and

   friends will contribute to our understanding of the

   physics and their design goals in due course.



   Bob  . . .

Erich_Weaver(at)URSCorp.c
Guest

Posted: Tue Sep 25, 2007 8:51 am Post subject: p-mag wiring

Thank you Bob for addressing this issue. I eagerly await Brad's reply.  Meanwhile, I can share my recent interaction with Brad on this issue:

 

 Some time ago, there was an issue with a customers pmags who had wired them per Bobs suggested method. The Emagair folks had a concern that the unit MAY have lost its timing due to switching from the upper switch position (bus power provided) to the middle position (bus power removed) and then back again to the upper postion at a time when the engine RPMs were not sufficient to allow the ignition to generate a spark on its own (i.e., around 900 rpm or less).  Due to the existing firmware, this action MAY have resulted in the loss of the timing memory in the unit.  As a result, the firmware was upgraded to prevent the timing memory loss from occurring.

 

 I told Brad that my dual pmags are wired per Bob's method, and his recommendation was to get the firmware upgrade, but that it was NOT worth the trouble of changing the wiring.  Their only concern at this point with Bob's method is that this is not the same wiring configuration used when they do their testing of the units, and therefore there is always some chance that test results may not be applicable under Bob's method or any other alternative wiring method. At the time of my conversation with Brad, provided the firmware upgrade was completed, there were no other known drawbacks for using Bob's method.

 

 This may be comments from the peanut gallery at this point. I am pleased to have Bob interacting with Emagair to get to the bottom of it.

 

 Erich Weaver

 

 This e-mail and any attachments are confidential. If you receive this message in error or are not the intended recipient, you should not retain, distribute, disclose or use any of this information and you should destroy the e-mail and any attachments or copies.  [quote][b]

nuckolls.bob(at)cox.net
Guest

Posted: Tue Sep 25, 2007 11:57 am Post subject: P-mag Wiring

 	  Quote: 	
		     I've crafted a note to Brad Demet with a goal

   of repairing a demonstrable disconnect in my understanding

   of e-Mag's functionality. I've posted a copy of my

   note to the list.



   Sorry to take so long to climb back into this particular

   'stew pot' . . . I've had too much stuff piled onto my

   plate over the past 6 months. I trust that Brad and

   friends will contribute to our understanding of the

   physics and their design goals in due course.


	


    I've had a response from Brad. I'm going to contact

    George Braly and see if we can plan a trip for early

    next week.



    Bob . . .



        ----------------------------------------

        ( "Problems are the price of progress. )

        ( Don't bring me anything but trouble. )

        ( Good news weakens me."               )

        (              -Charles F. Kettering-  )

        ----------------------------------------

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