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Dual circuit for J3300 EFI

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Peter H

Joined: 20 Mar 2007
Posts: 197

Posted: Tue May 22, 2007 9:07 pm Post subject: Dual circuit for J3300 EFI

First a big thank you Bob for the PM self exciting feature and the crowbar CB tripper. Watching the voltmeter stay up, and running the electronic ignition all with the master switch off was too much and I had to go home and have a couple of beers to celebrate it. Clever stuff.  

I have been finishing installation of a dual circuit based on Z-21A but I have wandered astray a bit as follows:  

   

1.         Re Z21-A I have connected the starter relay direct to the battery and not via the battery contactor. I am using the battery contactor only to interrupt the charging current (and to close the alternator relay.) I did this only because I do not know the logic for running the starter current through two series relays ?  

2.         I have retained the DPST master switch to isolate battery from alternator from main bus. This master connects the battery contactor which connects the alternator relay and it connects the main bus.   

3.         I have earthed the alternator relay coil and action it from the master switch through the battery contactor. I was thinking that the current from a failed regulator will otherwise go to earth through the master switch ? But how much current to expect here, I guess it is limited by the coil resistance. The method I have used saves another wire routed out to the engine bay.  

4.         For the ebus I just had to use those two big diodes which access either the battery or the alternator or both (normally both) each with a green LED signal light.  Z21-A offers power from battery plus alternator , or from battery but can not be switched to run from alternator only. So What ? Well it just appealed to me to be able to choose which power source in any emergency and the green lights are a feel good feature.  

   

I am offering this amendment fully expecting a flame out and ready to eat humble pie and learn some more, mean time I will stay off the beer.  

Circuit details follow :  

Peter  

   

   

[img]cid:image002.jpg(at)01C79D4A.742FD120[/img]

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nuckollsr(at)cox.net
Guest

Posted: Wed May 23, 2007 7:12 am Post subject: Dual circuit for J3300 EFI

It would be MUCH faster if you could sketch your

      changes for scanning and posting to the List. I'm

      not sure the images in my head based on your words

      match the reality of your proposal.



      Bob . . .



At 03:05 PM 5/23/2007 +1000, you wrote:



 	  Quote: 	
		  



First a big thank you Bob for the PM self exciting feature and the crowbar 

CB tripper. Watching the voltmeter stay up, and running the electronic 

ignition all with the master switch off was too much and I had to go home 

and have a couple of beers to celebrate it. Clever stuff.



I have been finishing installation of a dual circuit based on Z-21A but I 

have wandered astray a bit as follows:



1.         Re Z21-A I have connected the starter relay direct to the 

battery and not via the battery contactor. I am using the battery 

contactor only to interrupt the charging current (and to close the 

alternator relay.) I did this only because I do not know the logic for 

running the starter current through two series relays ?



2.         I have retained the DPST master switch to isolate battery from 

alternator from main bus. This master connects the battery contactor which 

connects the alternator relay and it connects the main bus.



3.         I have earthed the alternator relay coil and action it from the 

master switch through the battery contactor. I was thinking that the 

current from a failed regulator will otherwise go to earth through the 

master switch ? But how much current to expect here, I guess it is limited 

by the coil resistance. The method I have used saves another wire routed 

out to the engine bay.



4.         For the ebus I just had to use those two big diodes which 

access either the battery or the alternator or both (normally both) each 

with a green LED signal light.  Z21-A offers power from battery plus 

alternator , or from battery but can not be switched to run from 

alternator only. So What ? Well it just appealed to me to be able to 

choose which power source in any emergency and the green lights are a feel 

good feature.



I am offering this amendment fully expecting a flame out and ready to eat 

humble pie and learn some more, mean time I will stay off the beer.



Circuit details follow :



Peter



image002.jpg

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Checked by AVG.


	




        Bob . . .



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

        ( "Physics is like sex: sure, it may   )

        ( give some practical results, but     )

        ( that's not why we do it."            )

        (                                      )

        (                 Richard P. Feynman   )

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

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Peter H

Joined: 20 Mar 2007
Posts: 197

Posted: Wed May 23, 2007 2:04 pm Post subject: Dual circuit for J3300 EFI

Bob, Sorry about my attachment, the scan att is not accepted on the Yahoo

lists I know best. 

I should correct item 3 below, pls disregard my reference to the coil

resistance which is shunted by the crowbar, I hope that helps to make more

sense? 

But I am curious to know how much current to expect through the crowbar if

the regulator fails. I can still remember a boiling battery and think about

the amount of energy to be wasted through the crowbar.

Thanks,

Peter



--

nuckollsr(at)cox.net
Guest

Posted: Thu May 24, 2007 3:39 am Post subject: Dual circuit for J3300 EFI

At 08:02 AM 5/24/2007 +1000, you wrote:



[quote]

<peterjfharris(at)bigpond.com>



Bob, Sorry about my attachment, the scan att is not accepted on the Yahoo

lists I know best.

I should correct item 3 below, pls disregard my reference to the coil

resistance which is shunted by the crowbar, I hope that helps to make more

sense?

But I am curious to know how much current to expect through the crowbar if

the regulator fails. I can still remember a boiling battery and think about

the amount of energy to be wasted through the crowbar.

Thanks,

Peter



--

nuckollsr(at)cox.net
Guest

Posted: Thu May 24, 2007 3:42 am Post subject: Dual circuit for J3300 EFI

At 08:02 AM 5/24/2007 +1000, you wrote:



 	  Quote: 	
		  

<peterjfharris(at)bigpond.com>



Bob, Sorry about my attachment, the scan att is not accepted on the Yahoo

lists I know best.


	


  Don know about the Yahoo Lists but Matronics List will accept them.



 	  Quote: 	
		  I should correct item 3 below, pls disregard my reference to the coil

resistance which is shunted by the crowbar, I hope that helps to make more

sense?

But I am curious to know how much current to expect through the crowbar if

the regulator fails. I can still remember a boiling battery and think about

the amount of energy to be wasted through the crowbar.


	


   The crowbar OVM draws current only for milliseconds but it is

   high. On the order of 100-150 amps so that upstream break is

   opened in 10-20 milliseconds . . . then all the nonsense stops

   as breaker opens, current goes to zero, relay opens and alternator

   is shut down.



   Go to the website and search on "crowbar" for an explanation

   and a variety of discussions on how it works.

    Bob . . .

klehman(at)albedo.net
Guest

Posted: Thu May 24, 2007 5:10 pm Post subject: Dual circuit for J3300 EFI

Peter



You are right to ask a few more questions and learn more which is great 

but you are causing yourself difficulties by straying too far from the Z 

diagrams.



You should have a circuit breaker installed so that the OVM can trip the 

breaker and open the relay. The ovm will destroy itself if it shorts out 

the battery feed or the alternator feed. (Well actually it will likely 

blow up the diodes first in your diagram) You want the ovm to trip a 

breaker  that supplies power to the relay. The relay then disconnects 

the alternator.  I use a 2 amp breaker but 5 amp also works. The ovm is 

a short circuit when it activates. Take another look at the Z diagrams 

as I don't think you want the ovm in series with any diodes. One amp 

diodes will permanently pop like fuses if the ovm actuates in your diagram.



I do not use a separate starter contactor in addition to the contactor 

inside my starter BUT the power to my starter does flow through my main 

battery contactor!



Ken



Peter Harris wrote:



 	  Quote: 	
		    



 First a big thank you Bob for the PM self exciting feature and the 

 crowbar CB tripper. Watching the voltmeter stay up, and running the 

 electronic ignition all with the master switch off was too much and I 

 had to go home and have a couple of beers to celebrate it. Clever stuff.



 I have been finishing installation of a dual circuit based on Z-21A 

 but I have wandered astray a bit as follows:



  



 1.         Re Z21-A I have connected the starter relay direct to the 

 battery and not via the battery contactor. I am using the battery 

 contactor only to interrupt the charging current (and to close the 

 alternator relay.) I did this only because I do not know the logic for 

 running the starter current through two series relays ?



 2.         I have retained the DPST master switch to isolate battery 

 from alternator from main bus. This master connects the battery 

 contactor which connects the alternator relay and it connects the main 

 bus.



 3.         I have earthed the alternator relay coil and action it from 

 the master switch through the battery contactor. I was thinking that 

 the current from a failed regulator will otherwise go to earth through 

 the master switch ? But how much current to expect here, I guess it is 

 limited by the coil resistance. The method I have used saves another 

 wire routed out to the engine bay.



 4.         For the ebus I just had to use those two big diodes which 

 access either the battery or the alternator or both (normally both) 

 each with a green LED signal light.  Z21-A offers power from battery 

 plus alternator , or from battery but can not be switched to run from 

 alternator only. So What ? Well it just appealed to me to be able to 

 choose which power source in any emergency and the green lights are a 

 feel good feature.



  



 I am offering this amendment fully expecting a flame out and ready to 

 eat humble pie and learn some more, mean time I will stay off the beer.



 Circuit details follow :



 Peter

Peter H

Joined: 20 Mar 2007
Posts: 197

Posted: Thu May 24, 2007 10:00 pm Post subject: Dual circuit for J3300 EFI

Hi Ken,

Not sure if you saw my diagram. I have adopted the S704-1 alternator

disconnect relay with the crowbar across the coil same as Z-21A and Z-25.

The crowbar will shunt the coil and the relay will disconnect.

Instead of earthing the crowbar through the master switch I have set it

direct to earth. In my diagram the alternator relay will close when I close

the master switch which connects the battery to the alt relay diode and

feeds the coil, closing the alt relay.

I raised the question what happens when the regulator fails because if you

look at Z-21A the alt relay opens when the crowbar conducts but it will

close again when the crowbar stops conducting ie the unregulated output will

continue to feed to the coil + shunt crowbar and the crowbar would need to

continue to conduct this energy otherwise the relay will close again. Yes I

guess the diodes would pop. 

In Z21-A you would need to manually open the master switch to stop the

process. I don't see any other breaker that would interrupt power to the

relay? (I can see now that my coil earth would not allow this)

Am I missing something? 

What do you think Ken ?

Regards

Peter  



--

klehman(at)albedo.net
Guest

Posted: Sat May 26, 2007 3:21 pm Post subject: Dual circuit for J3300 EFI

Peter

Yes I saw your diagram.

You seem to be missing the point that the purpose of the crowbar ovm is 

to pop a circuit breaker which removes power to the relay. The relay 

stays unpowered until you manually reset the circuit breaker. Note the 2 

amp breaker to the right of the master switch in Z-21A.

Ken



Peter Harris wrote:



[quote]



Hi Ken,

Not sure if you saw my diagram. I have adopted the S704-1 alternator

disconnect relay with the crowbar across the coil same as Z-21A and Z-25.

The crowbar will shunt the coil and the relay will disconnect.

Instead of earthing the crowbar through the master switch I have set it

direct to earth. In my diagram the alternator relay will close when I close

the master switch which connects the battery to the alt relay diode and

feeds the coil, closing the alt relay.

I raised the question what happens when the regulator fails because if you

look at Z-21A the alt relay opens when the crowbar conducts but it will

close again when the crowbar stops conducting ie the unregulated output will

continue to feed to the coil + shunt crowbar and the crowbar would need to

continue to conduct this energy otherwise the relay will close again. Yes I

guess the diodes would pop. 

In Z21-A you would need to manually open the master switch to stop the

process. I don't see any other breaker that would interrupt power to the

relay? (I can see now that my coil earth would not allow this)

Am I missing something? 

What do you think Ken ?

Regards

Peter  



--

Peter H

Joined: 20 Mar 2007
Posts: 197

Posted: Sat May 26, 2007 3:42 pm Post subject: Dual circuit for J3300 EFI

Thanks Ken that clears it up somehow I missed that important detail!



Peter



--

Peter H

Joined: 20 Mar 2007
Posts: 197

Posted: Sat May 26, 2007 3:58 pm Post subject: Dual circuit for J3300 EFI

Thanks Bob,

I like the relay thing because it separates the two sources of power and I

can choose either battery or alternator independently.  Same principle as

your note 24 where the bridge rectifier is used to combine two sources for

the job and also used in Z19, also I understand that this idea is accepted

here by CASA as an independent dual circuit.

Peter



--

Peter H

Joined: 20 Mar 2007
Posts: 197

Posted: Sat May 26, 2007 7:35 pm Post subject: Dual circuit for J3300 EFI

That should read I like the diode thing. (I like relay things too)

Peter



--

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