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Electrical problems

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Jaybannist(at)cs.com
Guest

Posted: Tue Jul 01, 2008 5:23 pm Post subject: Electrical problems

Friends,

 

 I have asked these questions directly to several "gurus" and have gotten no response. Maybe someone on this forum can help me out. Since the forum does not allow enclosures, I have not attached my electrical schematic. Anyone wishing to help, please contact me directly and I will send a pdf of my schematic.

 

 I have just begun running the WW-built Corvair 2700 engine on my nearly completed Zodiac 601XL. At present, according to my Dynon EMS-D10, I have negative 3 or 4 amps output from my alternator. Obviously, I need to find out if that is actually the case, and if it is, why.

 

 1) Do I have the ammeter shunt correctly connected to the EMS? (Amps Low to the battery side of the shunt; Amps High to the main bus side)

 

 2) I have seen at least four different ways to connect the S704-1 Alternator OV Disconnect Relay.  Do I have mine correctly configured? (Must see schematic)

 

 And on another subject:

 

 3) I have each tach lead from the EMS connected through an in-line, fast blow, 0.5amp fuse, to the negative terminal of the coil. When the engine is turning 2,000 rpm (according to my hand held optical tach) the EMS tach is very erratic, reading from 1300 to 1800 rpm, running on either coil.  Is there something I can do to correct this?

 

 Thanks in advance - Jay Bannister     [quote][b]

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nuckolls.bob(at)cox.net
Guest

Posted: Tue Jul 01, 2008 7:28 pm Post subject: Electrical problems

At 09:19 PM 7/1/2008 -0400, you wrote:

 	  Quote: 	
		  Friends,



I have asked these questions directly to several "gurus" and have gotten 

no response. Maybe someone on this forum can help me out. Since the forum 

does not allow enclosures, I have not attached my electrical schematic. 

Anyone wishing to help, please contact me directly and I will send a pdf 

of my schematic.


	


  This forum DOES allow attachments. Suggest you

  repeat this note for the group. The reason I didn't

  respond to your direct inquiry was that I was out

  of town and just got back.

 	  Quote: 	
		  I have just begun running the WW-built Corvair 2700 engine on my nearly 

completed Zodiac 601XL. At present, according to my Dynon EMS-D10, I have 

negative 3 or 4 amps output from my alternator. Obviously, I need to find 

out if that is actually the case, and if it is, why.


	


   Your ammeter shunt is wired to read total electrical

   load and has nothing to do with alternator output.

   It has not been wired per the recommended architecture

   for an alternator load meter . . . therefore, the reading

   you're getting may be okay. Does your system have

   a voltmeter? What is the bus voltage when engine

   RPM is above 2000?

 	  Quote: 	
		  1) Do I have the ammeter shunt correctly connected to the EMS? (Amps Low 

to the battery side of the shunt; Amps High to the main bus side)


	


   Don't know what Lo and Hi means with respect to your particular

   ammeter.

 	  Quote: 	
		  2) I have seen at least four different ways to connect the S704-1 

Alternator OV Disconnect Relay.  Do I have mine correctly configured? 

(Must see schematic)


	


   It's fine

 	  Quote: 	
		  And on another subject:



3) I have each tach lead from the EMS connected through an in-line, fast 

blow, 0.5amp fuse, to the negative terminal of the coil. When the engine 

is turning 2,000 rpm (according to my hand held optical tach) the EMS tach 

is very erratic, reading from 1300 to 1800 rpm, running on either 

coil.  Is there something I can do to correct this?


	


    There might be an individual who knows if the

    EMS tachometer circuit is compatible with a Kettering

    ignition.



    Other noteworthy features in your schematic:

    Since you have an all-electric engine, suggest

    you run pumps and ignition systems directly from

    battery bus. The ignition systems should have their

    own fuses right at the bus (like your pumps) as opposed

    to the fuses downstream of the power switch.



    Suggest you run individual switches for each ignition

    and pump circuit so that a switch failure doesn't

    kill both pathways.



    Suggest flaps run from the main bus, not the endurance

    bus.

        Bob . . .



        ----------------------------------------)

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

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

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frank.hinde(at)hp.com
Guest

Posted: Wed Jul 02, 2008 7:28 am Post subject: Electrical problems

It depends on what you are trying to measure with the  shunt.....You can measure three things..1) Alternator output, 2) electrical  load, current going in/out of the battery.

  

 It seems to make most sense to measure the alternator  output as this should be regulating output depending on load...You can tell if  it isn't because you will also be monitoring buss voltage which should always be  around 14V...You can set an alarm in the EMS to go off at say 12.5V and 15.5V to  let you know when the alternator is acting up..In reality you don't even need to  measure amps if you do this.

  

 But anyway assuming you have the shunt installed in the  Alternator B lead, the high side will be on the alternator side and the low side  will be on the buss side.

  

 You could be measuring negative flow but it will max out at  about 4 amps as this is the excitation current...If you want to be sure start  adding elctrical load as you run the motor...If you got say 20 amps worth of  load (you can temporarilly hang some 12 v devices off the battery to get the 20  amps or so)  and the alternator is putting out minus 20A then you know you  have the leads reversed as there is no way the alternator can demand this  flow.

  

 If the amps stay at -3/4 then the alternator is not  charging...What do the battery volts do...it should be about 12V before you  start..and rise to 13.7 to 14.5V when running...If that is the case then the  alternator is working.

  

 As to the erratic tach reading..Are you using points or  electronic ignition?...It sounds like maybe you have a noisy signal coming off  the tach connection or maybe the volts you are seeing is over volting the Dynon  input.....Talk to Dynon as I bet they have a little smoothing circuit you could  build. I know several builders have used the WW with the Dynon so i bet they  have experience of this



   From:  owner-aeroelectric-list-server(at)matronics.com  [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of  Jaybannist(at)cs.com

Sent: Tuesday, July 01, 2008 6:20  PM

To: aeroelectric-list(at)matronics.com;  corvaircraft(at)mylist.net

Subject: Electrical  problems

 

Friends,



I have asked these questions  directly to several "gurus" and have gotten no response. Maybe someone on this  forum can help me out. Since the forum does not allow enclosures, I have not  attached my electrical schematic. Anyone wishing to help, please contact me  directly and I will send a pdf of my schematic.



I have just begun running  the WW-built Corvair 2700 engine on my nearly completed Zodiac 601XL. At  present, according to my Dynon EMS-D10, I have negative 3 or 4 amps output from  my alternator. Obviously, I need to find out if that is actually the case, and  if it is, why.



1) Do I have the ammeter shunt correctly connected to the  EMS? (Amps Low to the battery side of the shunt; Amps High to the main bus  side)



2) I have seen at least four different ways to connect the S704-1  Alternator OV Disconnect Relay.  Do I have mine correctly configured? (Must  see schematic)



And on another subject:



3) I have each tach lead  from the EMS connected through an in-line, fast blow, 0.5amp fuse, to the  negative terminal of the coil. When the engine is turning 2,000 rpm (according  to my hand held optical tach) the EMS tach is very erratic, reading from 1300 to  1800 rpm, running on either coil.  Is there something I can do to correct  this?



Thanks in advance - Jay Bannister  	  Quote: 	
		  



ist">http://www.matronics.com/Navigator?AeroElectric-List

ics.com

.matronics.com/contribution



	
  [quote][b]

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Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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