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Jabiru Alternator Wiring

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noelk

Joined: 05 Oct 2007
Posts: 10
Location: Canberra, Australia

Posted: Mon Oct 08, 2007 4:38 am Post subject: Jabiru Alternator Wiring

I am at the stage of planning the wiring for a Jabiru 3300  installation. It is one of the late model engines using the single phase  alternator with a Kubota RP201-53710 regulator. The aircraft will be used for  night VFR operations, so we want to be able to isolate the alternator and run on  battery power only in the event of alternator problems.

  

 I am only just starting to come to grips with the pecularities  of PM alternators. After having been given a reference to this site and the  Aeroelectric Connection by a friend, I have spent the last few days scanning the  list and reading the book.  This has clarified a  number of things, but I still have a few questions which, based on what I have  seen here so far, I am sure someone will be able to answer.

  

 I have seen a number of references to problems with load  dumping if the alternator is disconnected from the battery. Is this a problem  with PM alternators or only wound field ones?

  

 The simple Jabiru schematic in Figure Z-20 would appear to use  the same regulator looking at the pin-outs and wire colours, and would seem to  meet our requirement. Is the electrolytic capacitor at the output of the  regulatorfor noise filtering, or is it related to the load dumping problem?  

  

 I have also seen a couple of schematics on builders web sites  with slightly different approaches. One used the alternator switch to both  disconnect  the regulator sense line from the main bus and control a  relay connecting the regulator output line to the main bus, but no  capacitor. The other had a relay only in the regulator output line. The sense  line was left connected to the main bus, and would therefore have still been at  +12V ( at least until the battery discharged) if the alternator switch  was opened. Once again, no capacitor. What are the advantages or problems  associated with these approaches?

  

 Regards

  

 Noel Karppinen

    [quote][b]

klehman(at)albedo.net
Guest

Posted: Mon Oct 08, 2007 5:45 am Post subject: Jabiru Alternator Wiring

Hello Noel



I believe there are no load dump issues with PM alternators. The 

capacitor is for noise I think mostly for running without a battery in 

the circuit. My architecture never does that and since the capacitor 

didn't  make any difference for me I eliminated it.  I have a relay 

 between the alternator and the regulator for control and overvolt 

cutoff. It does not take a robust contactor there as it is AC current 

and that relay also lets me kill power to a misbehaving regulator. The 

B+ output of the regulator has a CB (a fuse would be fine) to protect 

against excess battery current going into a misbehaving regulator. My 

control switch does control the relay and provide power to the 

regulator. Some regulators draw a bit of current when not in use but 

regardless I want to shut off that wire on a misbehaving regulator. If 

you've detected a theme here - yes the regulator tends to be the most 

failure prone component so mine is on the cool side of the firewall 

where it gets warm to the touch but not hot.

Ken



Noel Karppinen wrote:



 	  Quote: 	
		   I am at the stage of planning the wiring for a Jabiru 3300 

 installation. It is one of the late model engines using the single 

 phase alternator with a Kubota RP201-53710 regulator. The aircraft 

 will be used for night VFR operations, so we want to be able to 

 isolate the alternator and run on battery power only in the event of 

 alternator problems.

  

 I am only just starting to come to grips with the pecularities of PM 

 alternators. After having been given a reference to this site and the 

 Aeroelectric Connection by a friend, I have spent the last few days 

 scanning the list and reading the book.  This has clarified a number 

 of things, but I still have a few questions which, based on what I 

 have seen here so far, I am sure someone will be able to answer.

  

 I have seen a number of references to problems with load dumping if 

 the alternator is disconnected from the battery. Is this a problem 

 with PM alternators or only wound field ones?

  

 The simple Jabiru schematic in Figure Z-20 would appear to use the 

 same regulator looking at the pin-outs and wire colours, and would 

 seem to meet our requirement. Is the electrolytic capacitor at the 

 output of the regulatorfor noise filtering, or is it related to the 

 load dumping problem?

  

 I have also seen a couple of schematics on builders web sites with 

 slightly different approaches. One used the alternator switch to both 

 disconnect  the regulator sense line from the main bus and control a 

 relay connecting the regulator output line to the main bus, but no 

 capacitor. The other had a relay only in the regulator output line. 

 The sense line was left connected to the main bus, and would therefore 

 have still been at +12V ( at least until the battery discharged) if 

 the alternator switch was opened. Once again, no capacitor. What are 

 the advantages or problems associated with these approaches?

  

 Regards

  

 Noel Karppinen

Peter H

Joined: 20 Mar 2007
Posts: 197

Posted: Mon Oct 08, 2007 1:22 pm Post subject: Jabiru Alternator Wiring

Ken,

Can you advise details of the AC relay and its connections? (Sometimes a 20A

fuse is used there)

Thanks

Peter H



--

klehman(at)albedo.net
Guest

Posted: Mon Oct 08, 2007 3:59 pm Post subject: Jabiru Alternator Wiring

Peter

I'm using a 40 amp rated automotive relay with push on connections. 

About a 1" cube.  Think they are sometimes called a VF4 by Tyco. $3. or 

maybe $4. from places like digi-key.

Ken



Peter Harris wrote:



[quote]



Ken,

Can you advise details of the AC relay and its connections? (Sometimes a 20A

fuse is used there)

Thanks

Peter H



--

Peter H

Joined: 20 Mar 2007
Posts: 197

Posted: Mon Oct 08, 2007 7:13 pm Post subject: Jabiru Alternator Wiring

Thanks ken 

What are the connections?

Peter

--

noelk

Joined: 05 Oct 2007
Posts: 10
Location: Canberra, Australia

Posted: Tue Oct 09, 2007 2:05 am Post subject: Jabiru Alternator Wiring

 	  Quote: 	
		  Hi KenYou said:>I have a relay 

 	  Quote: 	
		   between the alternator and the regulator for control and overvolt 

cutoff. It does not take a robust contactor there as it is AC current 

and that relay also lets me kill power to a misbehaving regulator. The 

B+ output of the regulator has a CB (a fuse would be fine) to protect 

against excess battery current going into a misbehaving regulator. 	


 Thanks for the infornmation. I had wondered about the  possibility of isolating the regulator from the alternator, but I have not seen  any previous references to this being done. Could you confirm that I have  understood this correctly. i.e that you do not have any relay between the  regulator output and the main bus, just the circuit breaker.
	


  

 Noel Karppinen

    [quote][b]

klehman(at)albedo.net
Guest

Posted: Tue Oct 09, 2007 5:03 am Post subject: Jabiru Alternator Wiring

Noel Karppinen wrote:

 	  Quote: 	
		  Hi Ken

You said:

>I have a relay 

> between the alternator and the regulator for control and overvolt 

>cutoff. It does not take a robust contactor there as it is AC current 

>and that relay also lets me kill power to a misbehaving regulator. The 

>B+ output of the regulator has a CB (a fuse would be fine) to protect 

>against excess battery current going into a misbehaving regulator.

 Thanks for the infornmation. I had wondered about the possibility of 

 isolating the regulator from the alternator, but I have not seen any 

 previous references to this being done. Could you confirm that I have 

 understood this correctly. i.e that you do not have any relay between 

 the regulator output and the main bus, just the circuit breaker.

 Noel Karppinen

Yes that is correct Noel.  Actually I thought the current Z figure had 

also been changed to show that now.  I run an electrically dependant 

engine so neither the alternator or the battery bus go through another 

battery contactor or relay.  Another reason to do this might be that I 

have also found that the John Deere regulator fails instantly if run 

with a totally dead battery -which is about the same as not having a 

battery connected.  (My little AGM batteries simply won't accept any 

significant current initially if they are totally dead)  Maybe the big 

capacitor would protect against that but I have doubts.

Peter the little VF4 relays just use our common PIDG push on 

connections.  You can mount the relay in a socket if you wish but that 

is not necessary. I think B&C also sell a slightly different suitable 

relay in a plastic case that does not use a socket.

Ken

Peter H

Joined: 20 Mar 2007
Posts: 197

Posted: Tue Oct 09, 2007 2:07 pm Post subject: Jabiru Alternator Wiring

Thanks Ken.

Peter



--

nuckolls.bob(at)cox.net
Guest

Posted: Wed Oct 10, 2007 4:56 am Post subject: Jabiru Alternator Wiring

At 09:00 AM 10/9/2007 -0400, you wrote:



 	  Quote: 	
		  



Noel Karppinen wrote:



>Hi Ken

>

>You said:

>

>>I have a relay between the alternator and the regulator for control and 

>>overvolt cutoff. It does not take a robust contactor there as it is AC 

>>current and that relay also lets me kill power to a misbehaving 

>>regulator. The B+ output of the regulator has a CB (a fuse would be 

>>fine) to protect against excess battery current going into a misbehaving 

>>regulator.

>

>Thanks for the infornmation. I had wondered about the possibility of 

>isolating the regulator from the alternator, but I have not seen any 

>previous references to this being done. Could you confirm that I have 

>understood this correctly. i.e that you do not have any relay between the 

>regulator output and the main bus, just the circuit breaker.

>

>Noel Karppinen



Yes that is correct Noel.  Actually I thought the current Z figure had 

also been changed to show that now.  I run an electrically dependant 

engine so neither the alternator or the battery bus go through another 

battery contactor or relay.  Another reason to do this might be that I 

have also found that the John Deere regulator fails instantly if run with 

a totally dead battery -which is about the same as not having a battery 

connected.  (My little AGM batteries simply won't accept any significant 

current initially if they are totally dead)  Maybe the big capacitor would 

protect against that but I have doubts.



Peter the little VF4 relays just use our common PIDG push on 

connections.  You can mount the relay in a socket if you wish but that is 

not necessary. I think B&C also sell a slightly different suitable relay 

in a plastic case that does not use a socket.



Ken

--

269.14.6/1060 - Release Date: 10/9/2007 4:43 PM





incoming mail is certified Virus Free.

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        Bob . . .



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

        ( "Problems are the price of progress. )

        ( Don't bring me anything but trouble. )

        ( Good news weakens me."               )

        (              -Charles F. Kettering-  )

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

DaveG601XL

Joined: 27 Oct 2006
Posts: 351
Location: Cincinnati, Oh

Posted: Wed Oct 10, 2007 11:04 am Post subject: Re: Jabiru Alternator Wiring

Bob,



If you meant to say something in your 10/09 posting, nothing got printed out that I can see.  I am also expecting to use a Jabiru engine with the PM alternator and am interested in your input to this thread.



Thanks,

_________________
David Gallagher
Cincinnati, OH area

nuckolls.bob(at)cox.net
Guest

Posted: Thu Oct 11, 2007 9:23 am Post subject: Jabiru Alternator Wiring

At 09:00 AM 10/9/2007 -0400, you wrote:



 	  Quote: 	
		  



Noel Karppinen wrote:



>Hi Ken

>

>You said:

>

>>I have a relay between the alternator and the regulator for control and 

>>overvolt cutoff. It does not take a robust contactor there as it is AC 

>>current and that relay also lets me kill power to a misbehaving 

>>regulator. The B+ output of the regulator has a CB (a fuse would be 

>>fine) to protect against excess battery current going into a misbehaving 

>>regulator.

>

>Thanks for the infornmation. I had wondered about the possibility of 

>isolating the regulator from the alternator, but I have not seen any 

>previous references to this being done. Could you confirm that I have 

>understood this correctly. i.e that you do not have any relay between the 

>regulator output and the main bus, just the circuit breaker.

>

>Noel Karppinen



Yes that is correct Noel.  Actually I thought the current Z figure had 

also been changed to show that now.  I run an electrically dependant 

engine so neither the alternator or the battery bus go through another 

battery contactor or relay.  Another reason to do this might be that I 

have also found that the John Deere regulator fails instantly if run with 

a totally dead battery -which is about the same as not having a battery 

connected.  (My little AGM batteries simply won't accept any significant 

current initially if they are totally dead)  Maybe the big capacitor would 

protect against that but I have doubts.



Peter the little VF4 relays just use our common PIDG push on 

connections.  You can mount the relay in a socket if you wish but that is 

not necessary. I think B&C also sell a slightly different suitable relay 

in a plastic case that does not use a socket.



Ken



      I need to update the Jabiru drawings to reflect the
	


      philosophy illustrated in Z-16 for Rotax. You can

      make the translation yourself. The same relay is used,

      it's simply moved from the DC output leg of the

      regulator/rectifier to the AC interface between

      alternator and regulator/rectifier.

        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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