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Rotax 912 UL Rectifier wiring

 
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hgmckay



Joined: 23 May 2006
Posts: 385

PostPosted: Tue Nov 20, 2018 1:48 pm    Post subject: Rotax 912 UL Rectifier wiring Reply with quote

I need some advice by anyone out there who may be able to clear up a question I have concerning checking the output wiring of the standard Rotax 912 rectifier used with the 912 UL engine. I have this rectifier on my  Allegro 2000 ELSA (912 UL engine). For additional information I am attaching my airplane wiring one line diagram that shows how my rectifier is wired. Also I want to make reference to a Blog article authored by Klaus Truemper titled “18 December 2012 Testing Rotax 912/914 Generator and Rectifier”. You can Google the title and read the article.

In the section of Mr. Truemper’s article (Testing Regulator/Rectifier) where he states “With the Master switch off: The above test (referring to the previous paragraph) should show 0 voltage for all three cases. I do not know what Mr. Truemper’s wiring diagram looked like because he did not offer one in his article.

After reading Mr. Truemper’s article and because of some perceived battery charging issues I was having with my airplane I thought I would check my rectifier according to his instructions in the article section titled (Testing Regulator/Rectifier). All the tests he listed (the same ones I did) fell within the values stated in his article except those tested with the Master switch “off”. In my case, with the Master switch “off” the voltage to ground on R, B+, and C each measured 12.7 VDC in stead of 0 VDC.

Again I don’t have Mr. Truemper’s wiring diagram, but in the wiring diagram shown in the Rotax 912 UL engine installation manual their wiring diagram indicates that there will be regular 12 VDC battery voltage on R, B+, and C when the master switch is “off”.

My question is this: Assuming there is a disconnect switch between terminal C and B+ in the open position (per instruction from Rotax to protect the battery from discharge), with the Master switch in the “off” position should I be measuring 12+VDC to ground on R, B+, and C rather than 0 VDC??

Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10


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PostPosted: Tue Nov 20, 2018 4:22 pm    Post subject: Rotax 912 UL Rectifier wiring Reply with quote

You don’t show a battery relay to that isolates the battery when all switches are off (as in shutdown) which is in the rotax install wiring diagram. I believe that is the master that Truemper’s speaking about.

Dave Alberti414-699-9312
On Nov 20, 2018, at 3:46 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
Quote:

I need some advice by anyone out there who may be able to clear up a question I have concerning checking the output wiring of the standard Rotax 912 rectifier used with the 912 UL engine. I have this rectifier on my Allegro 2000 ELSA (912 UL engine). For additional information I am attaching my airplane wiring one line diagram that shows how my rectifier is wired. Also I want to make reference to a Blog article authored by Klaus Truemper titled “18 December 2012 Testing Rotax 912/914 Generator and Rectifier”. You can Google the title and read the article.

In the section of Mr. Truemper’s article (Testing Regulator/Rectifier) where he states “With the Master switch off: The above test (referring to the previous paragraph) should show 0 voltage for all three cases. I do not know what Mr. Truemper’s wiring diagram looked like because he did not offer one in his article.

After reading Mr. Truemper’s article and because of some perceived battery charging issues I was having with my airplane I thought I would check my rectifier according to his instructions in the article section titled (Testing Regulator/Rectifier). All the tests he listed (the same ones I did) fell within the values stated in his article except those tested with the Master switch “off”. In my case, with the Master switch “off” the voltage to ground on R, B+, and C each measured 12.7 VDC in stead of 0 VDC.

Again I don’t have Mr. Truemper’s wiring diagram, but in the wiring diagram shown in the Rotax 912 UL engine installation manual their wiring diagram indicates that there will be regular 12 VDC battery voltage on R, B+, and C when the master switch is “off”.

My question is this: Assuming there is a disconnect switch between terminal C and B+ in the open position (per instruction from Rotax to protect the battery from discharge), with the Master switch in the “off” position should I be measuring 12+VDC to ground on R, B+, and C rather than 0 VDC??

Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10


<Electrical wiring one-line Diagram.pdf>


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hgmckay



Joined: 23 May 2006
Posts: 385

PostPosted: Tue Nov 20, 2018 6:01 pm    Post subject: Rotax 912 UL Rectifier wiring Reply with quote

Dave,

My battery is manually isolated by Breaker 13 shown within the “cloud” noted as Rev.#1 on the attached one line (better drawing than what I sent previous). All the Breakers mounted on the panel including Breaker 13 are Potter & Brumfield W23 Push Button Thermal circuit breakers that can also be used as manual isolation switches. I assumed the term “Master Switch” as used by Mr. Truemper meant the “Ignition Switch” as seen on my one line. With that switch in the “off” position and Breaker 13 open the voltage to ground on R, B+, and C each measured 12.7 VDC in stead of 0 VDC. This is the same wiring arrangement as shown in the Rotax 912 Installation Manual, page 46 of 66 Dated 1997 03 26. Unless I am “somewhere lost in translation”, If Mr. Truemper has his engine wired according to the Rotax manual (which is the same as mine, he should also be reading the voltage to ground on R, B+, and C each as 12+ VDC in stead of 0 VDC

Having said all this, have I lost my mind?? According to the attached one line is my electrical system wired correctly????[img]cid:image003.jpg(at)01D48113.F9B99D80[/img]


Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10

From: Dave Alberti (daberti(at)sbcglobal.net)
Sent: Tuesday, November 20, 2018 7:23 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rotax 912 UL Rectifier wiring


You don’t show a battery relay to that isolates the battery when all switches are off (as in shutdown) which is in the rotax install wiring diagram. I believe that is the master that Truemper’s speaking about.
Dave Alberti
414-699-9312

On Nov 20, 2018, at 3:46 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
Quote:

I need some advice by anyone out there who may be able to clear up a question I have concerning checking the output wiring of the standard Rotax 912 rectifier used with the 912 UL engine. I have this rectifier on my Allegro 2000 ELSA (912 UL engine). For additional information I am attaching my airplane wiring one line diagram that shows how my rectifier is wired. Also I want to make reference to a Blog article authored by Klaus Truemper titled “18 December 2012 Testing Rotax 912/914 Generator and Rectifier”. You can Google the title and read the article.

In the section of Mr. Truemper’s article (Testing Regulator/Rectifier) where he states “With the Master switch off: The above test (referring to the previous paragraph) should show 0 voltage for all three cases. I do not know what Mr. Truemper’s wiring diagram looked like because he did not offer one in his article.

After reading Mr. Truemper’s article and because of some perceived battery charging issues I was having with my airplane I thought I would check my rectifier according to his instructions in the article section titled (Testing Regulator/Rectifier). All the tests he listed (the same ones I did) fell within the values stated in his article except those tested with the Master switch “off”. In my case, with the Master switch “off” the voltage to ground on R, B+, and C each measured 12.7 VDC in stead of 0 VDC.

Again I don’t have Mr. Truemper’s wiring diagram, but in the wiring diagram shown in the Rotax 912 UL engine installation manual their wiring diagram indicates that there will be regular 12 VDC battery voltage on R, B+, and C when the master switch is “off”.

My question is this: Assuming there is a disconnect switch between terminal C and B+ in the open position (per instruction from Rotax to protect the battery from discharge), with the Master switch in the “off” position should I be measuring 12+VDC to ground on R, B+, and C rather than 0 VDC??

Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10


<Electrical wiring one-line Diagram.pdf>


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PostPosted: Tue Nov 20, 2018 6:39 pm    Post subject: Rotax 912 UL Rectifier wiring Reply with quote

Hugh, that does not isolate the battery, the rotax drawing drops at relay 19 and takes all voltage off the regulator at B+ and R.

Dave Alberti
414-699-9312

[quote] On Nov 20, 2018, at 7:59 PM, Hugh McKay <hgmckay(at)bellsouth.net> wrote:

Dave,

My battery is manually isolated by Breaker 13 shown within the “cloud” noted as Rev.#1 on the attached one line (better drawing than what I sent previous). All the Breakers mounted on the panel including Breaker 13 are Potter & Brumfield W23 Push Button Thermal circuit breakers that can also be used as manual isolation switches. I assumed the term “Master Switch” as used by Mr. Truemper meant the “Ignition Switch” as seen on my one line. With that switch in the “off” position and Breaker 13 open the voltage to ground on R, B+, and C each measured 12.7 VDC in stead of 0 VDC. This is the same wiring arrangement as shown in the Rotax 912 Installation Manual, page 46 of 66 Dated 1997 03 26. Unless I am “somewhere lost in translation”, If Mr. Truemper has his engine wired according to the Rotax manual (which is the same as mine, he should also be reading the voltage to ground on R, B+, and C each as 12+ VDC in stead of 0 VDC

Having said all this, have I lost my mind?? According to the attached one line is my electrical system wired correctly????<D29C00CAAAD94829847618F3128C3F05.jpg>


Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10

From: Dave Alberti
Sent: Tuesday, November 20, 2018 7:23 PM
To: rotaxengines-list(at)matronics.com
Subject: Re: Rotax 912 UL Rectifier wiring

You don’t show a battery relay to that isolates the battery when all switches are off (as in shutdown) which is in the rotax install wiring diagram. I believe that is the master that Truemper’s speaking about


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hgmckay



Joined: 23 May 2006
Posts: 385

PostPosted: Tue Nov 20, 2018 8:32 pm    Post subject: Rotax 912 UL Rectifier wiring Reply with quote

Dave,

Thanks for your clarification of the Rotax instruction concerning disconnecting the battery. I went back and read a similar article by Phil Lockwood called “Tips and Tricks for the Ideal Rotax 912 Installation” published in 2005. In that article he clearly states that the + battery wire that is connected to R, B+, and C must be disconnected from the battery. Based on my wiring one line drawing where would you recommend I move Breaker 13 to isolate the battery, and should I change the breaker to a larger amp rating?

Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10

From: Dave Alberti (daberti(at)sbcglobal.net)
Sent: Tuesday, November 20, 2018 9:41 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rotax 912 UL Rectifier wiring


Hugh, that does not isolate the battery, the rotax drawing drops at relay 19 and takes all voltage off the regulator at B+ and R. [img]cid:4E83A916-8B42-4F7C-8564-98D02BC6330B[/img]
Dave Alberti
414-699-9312

On Nov 20, 2018, at 7:59 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
Quote:

Dave,

My battery is manually isolated by Breaker 13 shown within the “cloud” noted as Rev.#1 on the attached one line (better drawing than what I sent previous). All the Breakers mounted on the panel including Breaker 13 are Potter & Brumfield W23 Push Button Thermal circuit breakers that can also be used as manual isolation switches. I assumed the term “Master Switch” as used by Mr. Truemper meant the “Ignition Switch” as seen on my one line. With that switch in the “off” position and Breaker 13 open the voltage to ground on R, B+, and C each measured 12.7 VDC in stead of 0 VDC. This is the same wiring arrangement as shown in the Rotax 912 Installation Manual, page 46 of 66 Dated 1997 03 26. Unless I am “somewhere lost in translation”, If Mr. Truemper has his engine wired according to the Rotax manual (which is the same as mine, he should also be reading the voltage to ground on R, B+, and C each as 12+ VDC in stead of 0 VDC

Having said all this, have I lost my mind?? According to the attached one line is my electrical system wired correctly????<D29C00CAAAD94829847618F3128C3F05.jpg>


Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10

From: Dave Alberti (daberti(at)sbcglobal.net)
Sent: Tuesday, November 20, 2018 7:23 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: RotaxEngines-List: Rotax 912 UL Rectifier wiring


You don’t show a battery relay to that isolates the battery when all switches are off (as in shutdown) which is in the rotax install wiring diagram. I believe that is the master that Truemper’s speaking about.
Dave Alberti
414-699-9312

On Nov 20, 2018, at 3:46 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
Quote:

I need some advice by anyone out there who may be able to clear up a question I have concerning checking the output wiring of the standard Rotax 912 rectifier used with the 912 UL engine. I have this rectifier on my Allegro 2000 ELSA (912 UL engine). For additional information I am attaching my airplane wiring one line diagram that shows how my rectifier is wired. Also I want to make reference to a Blog article authored by Klaus Truemper titled “18 December 2012 Testing Rotax 912/914 Generator and Rectifier”. You can Google the title and read the article.

In the section of Mr. Truemper’s article (Testing Regulator/Rectifier) where he states “With the Master switch off: The above test (referring to the previous paragraph) should show 0 voltage for all three cases. I do not know what Mr. Truemper’s wiring diagram looked like because he did not offer one in his article.

After reading Mr. Truemper’s article and because of some perceived battery charging issues I was having with my airplane I thought I would check my rectifier according to his instructions in the article section titled (Testing Regulator/Rectifier). All the tests he listed (the same ones I did) fell within the values stated in his article except those tested with the Master switch “off”. In my case, with the Master switch “off” the voltage to ground on R, B+, and C each measured 12.7 VDC in stead of 0 VDC.

Again I don’t have Mr. Truemper’s wiring diagram, but in the wiring diagram shown in the Rotax 912 UL engine installation manual their wiring diagram indicates that there will be regular 12 VDC battery voltage on R, B+, and C when the master switch is “off”.

My question is this: Assuming there is a disconnect switch between terminal C and B+ in the open position (per instruction from Rotax to protect the battery from discharge), with the Master switch in the “off” position should I be measuring 12+VDC to ground on R, B+, and C rather than 0 VDC??

Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10


<Electrical wiring one-line Diagram.pdf>


<D29C00CAAAD94829847618F3128C3F05.jpg>


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PostPosted: Wed Nov 21, 2018 3:06 am    Post subject: Rotax 912 UL Rectifier wiring Reply with quote

Hugh Rotax    Warn Terminal C should not be disconnected from Term B with a switch or fuse while the engine is running or regulator will be damaged. You need to remove CB13 and connect R B & C together.
Myself I have installed a battery contactor ((19) on rotax drawing)switched from a master switch,  and normal & alternative feed (small fuse direct from battery) switches to feed avionics bus.
IF you look in archives of aerolectric list you will find allsorts of information on rotax regulator and dawings. good place to ask electrical questions.
Clive
On Wed, 21 Nov 2018 at 04:38, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:

Quote:

Dave,
 
Thanks for your clarification of the Rotax instruction concerning disconnecting the battery. I went back and read a similar article by Phil Lockwood called “Tips and Tricks for the Ideal Rotax 912 Installation” published in 2005. In that article he clearly states that the + battery wire that is connected to R, B+, and C must be disconnected from the battery. Based on my wiring one line drawing where would you recommend I move Breaker 13 to isolate the battery, and should I change the breaker to a larger amp rating?
 
Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
 
Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10
 
From: Dave Alberti (daberti(at)sbcglobal.net)
Sent: Tuesday, November 20, 2018 9:41 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rotax 912 UL Rectifier wiring

 
Hugh, that does not isolate the battery, the rotax drawing drops at relay 19 and takes all voltage off the regulator at B+ and R.  
Dave Alberti
414-699-9312

On Nov 20, 2018, at 7:59 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
Quote:

Dave,
 
My battery is manually isolated by Breaker 13 shown within the “cloud” noted as Rev.#1 on the attached one line (better drawing than what I sent previous). All the Breakers mounted on the panel including Breaker 13 are Potter & Brumfield W23 Push Button Thermal circuit breakers that can also be used as manual isolation switches. I assumed the term “Master Switch” as used by Mr. Truemper meant the “Ignition Switch” as seen on my one line. With that switch in the “off” position and Breaker 13 open the voltage to ground on R, B+, and C each measured 12.7 VDC in stead of 0 VDC. This is the same wiring arrangement as shown in the Rotax 912 Installation Manual, page 46 of 66 Dated 1997 03 26. Unless I am “somewhere lost in translation”, If Mr. Truemper has his engine wired according to the Rotax manual (which is the same as mine, he should also be reading the voltage to ground on R, B+, and C each as 12+ VDC in stead of 0 VDC
 
Having said all this, have I lost my mind?? According to the attached one line is my electrical system wired correctly????<D29C00CAAAD94829847618F3128C3F05.jpg>
 
 
Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
 
Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10
 
From: Dave Alberti (daberti(at)sbcglobal.net)
Sent: Tuesday, November 20, 2018 7:23 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rotax 912 UL Rectifier wiring

 
You don’t show a battery relay to that isolates the battery when all switches are off (as in shutdown) which is in the rotax install wiring diagram.  I believe that is the master that  Truemper’s speaking about.
Dave Alberti
414-699-9312

On Nov 20, 2018, at 3:46 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
Quote:

I need some advice by anyone out there who may be able to clear up a question I have concerning checking the output wiring of the standard Rotax 912 rectifier used with the 912 UL engine. I have this rectifier on my  Allegro 2000 ELSA (912 UL engine). For additional information I am attaching my airplane wiring one line diagram that shows how my rectifier is wired. Also I want to make reference to a Blog article authored by Klaus Truemper titled “18 December 2012 Testing Rotax 912/914 Generator and Rectifier”. You can Google the title and read the article.
 
In the section of Mr. Truemper’s article (Testing Regulator/Rectifier) where he states “With the Master switch off: The above test (referring to the previous paragraph) should show 0 voltage for all three cases. I do not know what Mr. Truemper’s wiring diagram looked like because he did not offer one in his article.
 
After reading Mr. Truemper’s article and because of some perceived battery charging issues I was having with my airplane I thought I would check my rectifier according to his instructions in the article section titled (Testing Regulator/Rectifier). All the tests he listed (the same ones I did) fell within the values stated in his article except those tested with the Master switch “off”. In my case, with the Master switch “off” the voltage to ground on R, B+, and C each measured 12.7 VDC in stead of 0 VDC.
 
Again I don’t have Mr. Truemper’s wiring diagram, but in the wiring diagram shown in the Rotax 912 UL engine installation manual their wiring diagram indicates that there will be regular 12 VDC battery voltage on R, B+, and C when the master switch is “off”.
 
My question is this: Assuming there is a disconnect switch between terminal C and B+ in the open position (per instruction from Rotax to protect the battery from discharge), with the Master switch in the “off” position should I be measuring 12+VDC to ground on R, B+, and C rather than 0 VDC??
 
Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
 
Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10
 

<Electrical wiring one-line Diagram.pdf>
 

<D29C00CAAAD94829847618F3128C3F05.jpg>
 



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h&jeuropa



Joined: 07 Nov 2006
Posts: 416

PostPosted: Wed Nov 21, 2018 7:32 am    Post subject: Re: Rotax 912 UL Rectifier wiring Reply with quote

Hugh,

In your diagram switch/breaker CB13 only disconnects the C terminal of the Ducatti from R & B+.

In your diagram there is no way to disconnect the battery from R & B+ except by Fuse labeled Battery Booster (30A) or the 100A fuse (not advised).

Ducatti Terminal C has two functions. It provides voltage for the electronics inside the Ducatti for to operate. It also is used to sense bus voltage which in turn "tells" the Ducatti what the system requires, ie is the battery charged so no output is required, is the system working normally so just top up charging (output) is required or is the battery discharged so lots of output is required. Since C provides power to the Ducatti, it must be disconnected from the battery when the engine isn't running and providing voltage to the airplane bus or it will cause the battery to slowly discharge, just like leaving a light on.

From your diagram the ignition switch has four positions.

Pos 1, ACC will provide power to the bottom left side of the diagram, looks like flap position, front landing light, strobe lights, position lights, wing tip landing and tail lights and cabin lights. It also powers the left side of the diagram, sockets, GPS, Radio, ICM, Transponder and dual V/A meter.

Pos 2, OFF doesn't supply power to anything. However, C on the Ducatti will still be connected to the battery and slowly draining the battery because it powers the electronics inside the Ducatti.

Pos 3 probably labeled RUN supplies power exactly as Pos 1, ACC and also controls the Rotax ignition modules (the last implied, not shown).

Pos 4 probably labeled START provides power to the start contactor (relay) as well as the Rotax ignition modules (again implied, not shown).

So to answer your original question, with Master in Pos 2, OFF and the switch/breaker CB13 open (off) you should read 12 VDC on B+ and R and 0 on C. Turn switch/breaker CB13 closed (on) and you should read 12 VDC on R, B+ and C.

It appears that in Pos 4, START none of the ACC circuits will be powered but they will be when the switch returns to Pos 3, RUN. This means none of your lights radios or the dual V/A meter will function during START.

If you refer to Lockwoods article, note that you should not interrupt the connection between C and R/B+ during engine run and that connection should have low resistance, less than .2 VDC difference. It is OK to disconnect C from R and B+ when the engine is not running.

Your diagram should work just fine. Just be sure to turn ON switch/breaker CB13 prior to or right after start (at which time light 16 should go off indicating the Ducatti is on line and working) and always turn OFF switch/breaker CB13 after engine shut down.

Hope this helps.

Jim Butcher


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PostPosted: Wed Nov 21, 2018 10:26 am    Post subject: Rotax 912 UL Rectifier wiring Reply with quote

Hugh, I have an actual contractor (looks like a solenoid) from Spruce designed to use for this application. Mine is on the firewall near my battery. My comparison position is prior to your ammeter shunt. You would have to wire your breaker so that when closed it would energize the solenoid to close the circuit supplying 12 volts to B+, R and C. I use a switch like Cessna, red split battery alternator .

Dave Alberti

[quote] On Nov 20, 2018, at 10:31 PM, Hugh McKay <hgmckay(at)bellsouth.net> wrote:

Dave,

Thanks for your clarification of the Rotax instruction concerning disconnecting the battery. I went back and read a similar article by Phil Lockwood called “Tips and Tricks for the Ideal Rotax 912 Installation” published in 2005. In that article he clearly states that the + battery wire that is connected to R, B+, and C must be disconnected from the battery. Based on my wiring one line drawing where would you recommend I move Breaker 13 to isolate the battery, and should I change the breaker to a larger amp rating?

Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10

From: Dave Alberti
Sent: Tuesday, November 20, 2018 9:41 PM
To: rotaxengines-list(at)matronics.com
Subject: Re: Rotax 912 UL Rectifier wiring

Hugh, that does not isolate the battery, the rotax drawing drops at relay 19 and takes all voltage off the regulator at B+ and R.

Dave Alberti
414-699-9312

On Nov 20, 2018, at 7:59 PM, Hugh McKay <hgmckay(at)bellsouth.net> wrote:

Dave,

My battery is manually isolated by Breaker 13 shown within the “cloud” noted as Rev.#1 on the attached one line (better drawing than what I sent previous). All the Breakers mounted on the panel including Breaker 13 are Potter & Brumfield W23 Push Button Thermal circuit breakers that can also be used as manual isolation switches. I assumed the term “Master Switch” as used by Mr. Truemper meant the “Ignition Switch” as seen on my one line. With that switch in the “off” position and Breaker 13 open the voltage to ground on R, B+, and C each measured 12.7 VDC in stead of 0 VDC. This is the same wiring arrangement as shown in the Rotax 912 Installation Manual, page 46 of 66 Dated 1997 03 26. Unless I am “somewhere lost in translation”, If Mr. Truemper has his engine wired according to the Rotax manual (which is the same as mine, he should also be reading the voltage to ground on R, B+, and C each as 12+ VDC in stead of 0 VDC

Having said all this, have I lost my mind?? According to the attached one line is my electrical system wired correctly????<D29C00CAAAD94829847618F3128C3F05.jpg>


Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10

From: Dave Alberti
Sent: Tuesday, November 20, 2018 7:23 PM
To: rotaxengines-list(at)matronics.com
Subject: Re: Rotax 912 UL Rectifier wiring

You don’t show a battery relay to that isolates the battery when all switches are off (as in shutdown) which is in the rotax install wiring diagram. I believe that is the master that Truemper’s speaking about


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hgmckay



Joined: 23 May 2006
Posts: 385

PostPosted: Wed Nov 21, 2018 6:39 pm    Post subject: Rotax 912 UL Rectifier wiring Reply with quote

Dave,
I am not an electrical guru so my understanding of electrical terms and functions in an electrical circuit is very limited. I do need to limit the amount of changes to my panel simply due to space. Therefore, I am attaching a scanned sketch of what I propose doing, hoping that it will be safe and meet the electrical requirements for safe operation of the rectifier and give the isolation requirements described by Rotax. Please refer to the attached sketch and the original one line to compare the proposed changes to the original.

You will note on the sketch that I have a common point where I connect 5 wires to a common connection (R, B+, C, the wire from the Capacitor, and the wire from the 30 Amp fuse). Between the 30 Amp fuse and the shunt I propose using my existing Breaker 13 (Potter & Brumfield Series W23 Push Button Thermal circuit breaker W23-X1A1G5 (which is certified to be used as a manual push to close/pull to open disconnect) rated for 5 Amps having a Trip time at 200% rating of 6-22 seconds. If necessary I can replace this same identical Potter & Brumfield breaker with Amp ratings up to 50 Amps. By the way all the breakers shown on the one line are panel mounted Potter & Brumfield Series W23 Push Button Thermal circuit breakers. I use these breakers routinely as disconnect switches to isolate certain sections of the electrical system on start-up. Do you find any flaws in this sketch?

Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10

From: Dave Alberti (daberti(at)sbcglobal.net)
Sent: Wednesday, November 21, 2018 1:28 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rotax 912 UL Rectifier wiring


Hugh, I have an actual contractor (looks like a solenoid) from Spruce designed to use for this application. Mine is on the firewall near my battery. My comparison position is prior to your ammeter shunt. You would have to wire your breaker so that when closed it would energize the solenoid to close the circuit supplying 12 volts to B+, R and C. I use a switch like Cessna, red split battery alternator .
Dave Alberti
On Nov 20, 2018, at 10:31 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
Quote:

Dave,

Thanks for your clarification of the Rotax instruction concerning disconnecting the battery. I went back and read a similar article by Phil Lockwood called “Tips and Tricks for the Ideal Rotax 912 Installation” published in 2005. In that article he clearly states that the + battery wire that is connected to R, B+, and C must be disconnected from the battery. Based on my wiring one line drawing where would you recommend I move Breaker 13 to isolate the battery, and should I change the breaker to a larger amp rating?

Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10

From: Dave Alberti (daberti(at)sbcglobal.net)
Sent: Tuesday, November 20, 2018 9:41 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rotax 912 UL Rectifier wiring


Hugh, that does not isolate the battery, the rotax drawing drops at relay 19 and takes all voltage off the regulator at B+ and R. [img]cid:image001.png(at)01D481E2.788103A0[/img]
Dave Alberti
414-699-9312

On Nov 20, 2018, at 7:59 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
Quote:

Dave,

My battery is manually isolated by Breaker 13 shown within the “cloud” noted as Rev.#1 on the attached one line (better drawing than what I sent previous). All the Breakers mounted on the panel including Breaker 13 are Potter & Brumfield W23 Push Button Thermal circuit breakers that can also be used as manual isolation switches. I assumed the term “Master Switch” as used by Mr. Truemper meant the “Ignition Switch” as seen on my one line. With that switch in the “off” position and Breaker 13 open the voltage to ground on R, B+, and C each measured 12.7 VDC in stead of 0 VDC. This is the same wiring arrangement as shown in the Rotax 912 Installation Manual, page 46 of 66 Dated 1997 03 26. Unless I am “somewhere lost in translation”, If Mr. Truemper has his engine wired according to the Rotax manual (which is the same as mine, he should also be reading the voltage to ground on R, B+, and C each as 12+ VDC in stead of 0 VDC

Having said all this, have I lost my mind?? According to the attached one line is my electrical system wired correctly????<D29C00CAAAD94829847618F3128C3F05.jpg>


Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10

From: Dave Alberti (daberti(at)sbcglobal.net)
Sent: Tuesday, November 20, 2018 7:23 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rotax 912 UL Rectifier wiring


You don’t show a battery relay to that isolates the battery when all switches are off (as in shutdown) which is in the rotax install wiring diagram. I believe that is the master that Truemper’s speaking about.
Dave Alberti
414-699-9312

On Nov 20, 2018, at 3:46 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
Quote:

I need some advice by anyone out there who may be able to clear up a question I have concerning checking the output wiring of the standard Rotax 912 rectifier used with the 912 UL engine. I have this rectifier on my Allegro 2000 ELSA (912 UL engine). For additional information I am attaching my airplane wiring one line diagram that shows how my rectifier is wired. Also I want to make reference to a Blog article authored by Klaus Truemper titled “18 December 2012 Testing Rotax 912/914 Generator and Rectifier”. You can Google the title and read the article.

In the section of Mr. Truemper’s article (Testing Regulator/Rectifier) where he states “With the Master switch off: The above test (referring to the previous paragraph) should show 0 voltage for all three cases. I do not know what Mr. Truemper’s wiring diagram looked like because he did not offer one in his article.

After reading Mr. Truemper’s article and because of some perceived battery charging issues I was having with my airplane I thought I would check my rectifier according to his instructions in the article section titled (Testing Regulator/Rectifier). All the tests he listed (the same ones I did) fell within the values stated in his article except those tested with the Master switch “off”. In my case, with the Master switch “off” the voltage to ground on R, B+, and C each measured 12.7 VDC in stead of 0 VDC.

Again I don’t have Mr. Truemper’s wiring diagram, but in the wiring diagram shown in the Rotax 912 UL engine installation manual their wiring diagram indicates that there will be regular 12 VDC battery voltage on R, B+, and C when the master switch is “off”.

My question is this: Assuming there is a disconnect switch between terminal C and B+ in the open position (per instruction from Rotax to protect the battery from discharge), with the Master switch in the “off” position should I be measuring 12+VDC to ground on R, B+, and C rather than 0 VDC??

Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10


<Electrical wiring one-line Diagram.pdf>


<D29C00CAAAD94829847618F3128C3F05.jpg>


<image1.png>


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PostPosted: Wed Nov 21, 2018 7:40 pm    Post subject: Rotax 912 UL Rectifier wiring Reply with quote

Hugh, the primary function of breakers and fuses is to protect the wire. The size of the wire is sized to the expected load and voltage drop due to wire length. Placing a 5 amp breaker ahead of a 30 amp fuse is just a wasted fuse installation. The fuse will never see a load greater than 5 amps. Replacing the 5 amp with a 30 makes the fuse redundant and unnecessary. If the wire downstream is incapable of carrying more than 30 amps it becomes the fuse. I have seen panels that smoked in RV’s and cars and if it happens in a plane you want to be able to strip the load with the fewest switches possible. Your drawing will work to isolate the charging circuit only if the wire size matches the expected load with the caveat being you have no protection for the wire between the breaker and the battery.

Dave Alberti

[quote] On Nov 21, 2018, at 8:38 PM, Hugh McKay <hgmckay(at)bellsouth.net> wrote:

Dave,
I am not an electrical guru so my understanding of electrical terms and functions in an electrical circuit is very limited. I do need to limit the amount of changes to my panel simply due to space. Therefore, I am attaching a scanned sketch of what I propose doing, hoping that it will be safe and meet the electrical requirements for safe operation of the rectifier and give the isolation requirements described by Rotax. Please refer to the attached sketch and the original one line to compare the proposed changes to the original.

You will note on the sketch that I have a common point where I connect 5 wires to a common connection (R, B+, C, the wire from the Capacitor, and the wire from the 30 Amp fuse). Between the 30 Amp fuse and the shunt I propose using my existing Breaker 13 (Potter & Brumfield Series W23 Push Button Thermal circuit breaker W23-X1A1G5 (which is certified to be used as a manual push to close/pull to open disconnect) rated for 5 Amps having a Trip time at 200% rating of 6-22 seconds. If necessary I can replace this same identical Potter & Brumfield breaker with Amp ratings up to 50 Amps. By the way all the breakers shown on the one line are panel mounted Potter & Brumfield Series W23 Push Button Thermal circuit breakers. I use these breakers routinely as disconnect switches to isolate certain sections of the electrical system on start-up. Do you find any flaws in this sketch?

Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10

From: Dave Alberti
Sent: Wednesday, November 21, 2018 1:28 PM
To: rotaxengines-list(at)matronics.com
Subject: Re: Rotax 912 UL Rectifier wiring

Hugh, I have an actual contractor (looks like a solenoid) from Spruce designed to use for this application. Mine is on the firewall near my battery. My comparison position is prior to your ammeter shunt. You would have to wire your breaker so that when closed it would energize the solenoid to close the circuit supplying 12 volts to B+, R and C. I use a switch like Cessna, red split battery alternator .

Dave Alberti

On Nov 20, 2018, at 10:31 PM, Hugh McKay <hgmckay(at)bellsouth.net> wrote:

Dave,

Thanks for your clarification of the Rotax instruction concerning disconnecting the battery. I went back and read a similar article by Phil Lockwood called “Tips and Tricks for the Ideal Rotax 912 Installation” published in 2005. In that article he clearly states that the + battery wire that is connected to R, B+, and C must be disconnected from the battery. Based on my wiring one line drawing where would you recommend I move Breaker 13 to isolate the battery, and should I change the breaker to a larger amp rating?

Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10

From: Dave Alberti
Sent: Tuesday, November 20, 2018 9:41 PM
To: rotaxengines-list(at)matronics.com
Subject: Re: Rotax 912 UL Rectifier wiring

Hugh, that does not isolate the battery, the rotax drawing drops at relay 19 and takes all voltage off the regulator at B+ and R. <DADA423704E04780947357B5BB6383CA.png>

Dave Alberti
414-699-9312

On Nov 20, 2018, at 7:59 PM, Hugh McKay <hgmckay(at)bellsouth.net> wrote:

Dave,

My battery is manually isolated by Breaker 13 shown within the “cloud” noted as Rev.#1 on the attached one line (better drawing than what I sent previous). All the Breakers mounted on the panel including Breaker 13 are Potter & Brumfield W23 Push Button Thermal circuit breakers that can also be used as manual isolation switches. I assumed the term “Master Switch” as used by Mr. Truemper meant the “Ignition Switch” as seen on my one line. With that switch in the “off” position and Breaker 13 open the voltage to ground on R, B+, and C each measured 12.7 VDC in stead of 0 VDC. This is the same wiring arrangement as shown in the Rotax 912 Installation Manual, page 46 of 66 Dated 1997 03 26. Unless I am “somewhere lost in translation”, If Mr. Truemper has his engine wired according to the Rotax manual (which is the same as mine, he should also be reading the voltage to ground on R, B+, and C each as 12+ VDC in stead of 0 VDC

Having said all this, have I lost my mind?? According to the attached one line is my electrical system wired correctly????<D29C00CAAAD94829847618F3128C3F05.jpg>


Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10

From: Dave Alberti
Sent: Tuesday, November 20, 2018 7:23 PM
To: rotaxengines-list(at)matronics.com
Subject: Re: Rotax 912 UL Rectifier wiring

You don’t show a battery relay to that isolates the battery when all switches are off (as in shutdown) which is in the rotax install wiring diagram. I believe that is the master that Truemper’s speaking about


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Back to top
hgmckay



Joined: 23 May 2006
Posts: 385

PostPosted: Fri Nov 23, 2018 1:41 pm    Post subject: Rotax 912 UL Rectifier wiring Reply with quote

Dave,

Thank you for the additional electrical information and instruction.  Referring to the proposed sketch I sent to you, I am proposing a revision; to change out the existing 5 Amp Breaker/switch 13 to a similar 30 Amp Breaker/switch and reconnect the wiring as follows:  connect the new 30 Amp breaker/switch between the existing 30 Amp fuse and the rectifier. All the connecting wire from the shunt/30 Amp fuse/ 30 Amp breaker 13, to the common connection point of the four rectifier wires R, B+, C, and the + capacitor wire is stranded # 10 AWG THHN.

I have made a list of all my electrical devices that would be operating during taxi, take-off, cruise, and landing and calculated the electrical load for each case in amps. The largest load demand is during take-off and landing. The load demand during cruise is somewhat less. I notice in Phil Lockwood’s article he states that one should expect the Rotax Rectifier/regulator to have a maximum output of approximately 18 Amps DC. My total installed electrical load is about 27 amps DC. This means that if during flight all of this installed electrical load was connected, the rectifier could not meet the demand and the battery would be making up the difference, thus draining the battery. But this is not the case during cruise, but is the case during take-off and landing. My calculated take-off and landing load demand is about 21 Amps DC, while the cruise electrical load demand is around 11.5 Amps DC. If my thought logic is correct this means that during the short periods of take-offs and landings my battery would not be charging (red light on), but during cruise it should be charging (red light off). Correct?? By still using a Potter & Brumfield W23 series W23-X1A1G-30 push/pull button breaker at this point in the wiring I believe it not only protects the wire but still allows me to isolate the battery from the rectifier when the engine is no running.

Sorry to be asking you to look at this again. Comments, advice???

Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10

From: Dave Alberti (daberti(at)sbcglobal.net)
Sent: Wednesday, November 21, 2018 10:42 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rotax 912 UL Rectifier wiring


Hugh, the primary function of breakers and fuses is to protect the wire. The size of the wire is sized to the expected load and voltage drop due to wire length. Placing a 5 amp breaker ahead of a 30 amp fuse is just a wasted fuse installation. The fuse will never see a load greater than 5 amps. Replacing the 5 amp with a 30 makes the fuse redundant and unnecessary. If the wire downstream is incapable of carrying more than 30 amps it becomes the fuse. I have seen panels that smoked in RV’s and cars and if it happens in a plane you want to be able to strip the load with the fewest switches possible. Your drawing will work to isolate the charging circuit only if the wire size matches the expected load with the caveat being you have no protection for the wire between the breaker and the battery.
Dave Alberti
On Nov 21, 2018, at 8:38 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
Quote:

Dave,
I am not an electrical guru so my understanding of electrical terms and functions in an electrical circuit is very limited. I do need to limit the amount of changes to my panel simply due to space. Therefore, I am attaching a scanned sketch of what I propose doing, hoping that it will be safe and meet the electrical requirements for safe operation of the rectifier and give the isolation requirements described by Rotax. Please refer to the attached sketch and the original one line to compare the proposed changes to the original.

You will note on the sketch that I have a common point where I connect 5 wires to a common connection (R, B+, C, the wire from the Capacitor, and the wire from the 30 Amp fuse). Between the 30 Amp fuse and the shunt I propose using my existing Breaker 13 (Potter & Brumfield Series W23 Push Button Thermal circuit breaker W23-X1A1G5 (which is certified to be used as a manual push to close/pull to open disconnect) rated for 5 Amps having a Trip time at 200% rating of 6-22 seconds. If necessary I can replace this same identical Potter & Brumfield breaker with Amp ratings up to 50 Amps. By the way all the breakers shown on the one line are panel mounted Potter & Brumfield Series W23 Push Button Thermal circuit breakers. I use these breakers routinely as disconnect switches to isolate certain sections of the electrical system on start-up. Do you find any flaws in this sketch?

Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10

From: Dave Alberti (daberti(at)sbcglobal.net)
Sent: Wednesday, November 21, 2018 1:28 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rotax 912 UL Rectifier wiring


Hugh, I have an actual contractor (looks like a solenoid) from Spruce designed to use for this application. Mine is on the firewall near my battery. My comparison position is prior to your ammeter shunt. You would have to wire your breaker so that when closed it would energize the solenoid to close the circuit supplying 12 volts to B+, R and C. I use a switch like Cessna, red split battery alternator .
Dave Alberti
On Nov 20, 2018, at 10:31 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
Quote:

Dave,

Thanks for your clarification of the Rotax instruction concerning disconnecting the battery. I went back and read a similar article by Phil Lockwood called “Tips and Tricks for the Ideal Rotax 912 Installation” published in 2005. In that article he clearly states that the + battery wire that is connected to R, B+, and C must be disconnected from the battery. Based on my wiring one line drawing where would you recommend I move Breaker 13 to isolate the battery, and should I change the breaker to a larger amp rating?

Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10

From: Dave Alberti (daberti(at)sbcglobal.net)
Sent: Tuesday, November 20, 2018 9:41 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rotax 912 UL Rectifier wiring


Hugh, that does not isolate the battery, the rotax drawing drops at relay 19 and takes all voltage off the regulator at B+ and R. <DADA423704E04780947357B5BB6383CA.png>
Dave Alberti
414-699-9312

On Nov 20, 2018, at 7:59 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
Quote:

Dave,

My battery is manually isolated by Breaker 13 shown within the “cloud” noted as Rev.#1 on the attached one line (better drawing than what I sent previous). All the Breakers mounted on the panel including Breaker 13 are Potter & Brumfield W23 Push Button Thermal circuit breakers that can also be used as manual isolation switches. I assumed the term “Master Switch” as used by Mr. Truemper meant the “Ignition Switch” as seen on my one line. With that switch in the “off” position and Breaker 13 open the voltage to ground on R, B+, and C each measured 12.7 VDC in stead of 0 VDC. This is the same wiring arrangement as shown in the Rotax 912 Installation Manual, page 46 of 66 Dated 1997 03 26. Unless I am “somewhere lost in translation”, If Mr. Truemper has his engine wired according to the Rotax manual (which is the same as mine, he should also be reading the voltage to ground on R, B+, and C each as 12+ VDC in stead of 0 VDC

Having said all this, have I lost my mind?? According to the attached one line is my electrical system wired correctly????<D29C00CAAAD94829847618F3128C3F05.jpg>


Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10

From: Dave Alberti (daberti(at)sbcglobal.net)
Sent: Tuesday, November 20, 2018 7:23 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rotax 912 UL Rectifier wiring


You don’t show a battery relay to that isolates the battery when all switches are off (as in shutdown) which is in the rotax install wiring diagram. I believe that is the master that Truemper’s speaking about.
Dave Alberti
414-699-9312

On Nov 20, 2018, at 3:46 PM, Hugh McKay <hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)> wrote:
Quote:

I need some advice by anyone out there who may be able to clear up a question I have concerning checking the output wiring of the standard Rotax 912 rectifier used with the 912 UL engine. I have this rectifier on my Allegro 2000 ELSA (912 UL engine). For additional information I am attaching my airplane wiring one line diagram that shows how my rectifier is wired. Also I want to make reference to a Blog article authored by Klaus Truemper titled “18 December 2012 Testing Rotax 912/914 Generator and Rectifier”. You can Google the title and read the article.

In the section of Mr. Truemper’s article (Testing Regulator/Rectifier) where he states “With the Master switch off: The above test (referring to the previous paragraph) should show 0 voltage for all three cases. I do not know what Mr. Truemper’s wiring diagram looked like because he did not offer one in his article.

After reading Mr. Truemper’s article and because of some perceived battery charging issues I was having with my airplane I thought I would check my rectifier according to his instructions in the article section titled (Testing Regulator/Rectifier). All the tests he listed (the same ones I did) fell within the values stated in his article except those tested with the Master switch “off”. In my case, with the Master switch “off” the voltage to ground on R, B+, and C each measured 12.7 VDC in stead of 0 VDC.

Again I don’t have Mr. Truemper’s wiring diagram, but in the wiring diagram shown in the Rotax 912 UL engine installation manual their wiring diagram indicates that there will be regular 12 VDC battery voltage on R, B+, and C when the master switch is “off”.

My question is this: Assuming there is a disconnect switch between terminal C and B+ in the open position (per instruction from Rotax to protect the battery from discharge), with the Master switch in the “off” position should I be measuring 12+VDC to ground on R, B+, and C rather than 0 VDC??

Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10


<Electrical wiring one-line Diagram.pdf>


<D29C00CAAAD94829847618F3128C3F05.jpg>


<image1.png>


<Allegro 2000 Wiring Sketch.pdf>

<DADA423704E04780947357B5BB6383CA.png>


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h&jeuropa



Joined: 07 Nov 2006
Posts: 416

PostPosted: Mon Nov 26, 2018 1:52 pm    Post subject: Re: Rotax 912 UL Rectifier wiring Reply with quote

I have Lockwood’s article. While the text does indeed state “the positive charging wire which is connected to R, B+ and C must not remain connected to the positive side of the battery when the master switch is turned off or the battery will discharge when the engine is not running”, note the Attention box on the same page which states “during engine stop, break circuit between battery and terminal C to avoid discharge of battery”. This last statement is correct. R and B+ can remain connected without problem.

The original circuit you submitted from Allegro provides correct electrical operation if you remember to always turn off breaker 13 when you shut down the engine and turn it on after engine start. R and B+ will always have 12VDC on them but C will only have 12VDC when breaker 13 is on.

If you wish to control when 12VDC is applied to R and B+, you might want to add a contactor or solenoid like Aircraft Spruce PN STS-12M. The problem with that is the solenoid itself requires about 3 amps to operate which is a problem when you don’t have much electrical capacity as your load analysis shows.

Are you certain about your load analysis? Are the position and strobe lights LED? The Rotax Ducatti will operate at 11 amps OK but much more than that it will fail from overheating causing internal components to fail. It will not reliably operate at 18 amps no matter what the documentation says:)

Let me know if I can help further. What is the original charging problem that started this thread?

Jim Butcher
Europa XS, Rotax 914 1000 hours


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h&jeuropa



Joined: 07 Nov 2006
Posts: 416

PostPosted: Tue Nov 27, 2018 7:56 am    Post subject: Re: Rotax 912 UL Rectifier wiring Reply with quote

Hugh,

If you want to disconnect the Ducatti per the Lockwood article, here is a simple way to do that.

Purchase a S8009-1 relay from BandC.aero
Wire the relay into the wire just ahead or after the 30A fuse.
Use the NO and COM contacts.
Connect one coil lead to the COM contact (will always have 12 VDC on it).
Remove the existing BR15 breaker from the C terminal and replace that with a wire (same size as existing). This will tie C to R and B+.
Re use the existing BR15 to operate the relay. Wire one side to the other coil lead and the other side to ground.
I've attached a sketch showing all this.

In normal operation the existing light which is connected to C will illuminate when the relay is closed and the Ducatti is connected to the battery. The lamp connected to the L terminal will also operate as usual, illuminated when the Ducatti is not keeping up with demand.

Start your engine with the BR 15 breaker off. Neither light should illuminate. After start, turn on the breaker. The light attached to C should illuminate showing the Ducatti is connected to the battery (and hopefully charging). The other light will illuminate depending on the electrical load and should go out when the charging system is "keeping up". Note that the charging system doesn't generate much at idle speed. It really only works well at cruise RPM.

Hope this helps.

Jim Butcher


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h&jeuropa



Joined: 07 Nov 2006
Posts: 416

PostPosted: Tue Nov 27, 2018 9:01 am    Post subject: Re: Rotax 912 UL Rectifier wiring Reply with quote

Hugh,

After posting the above post, I was thinking, why add complexity. The circuit from Allegro is in accordance with Rotax requirements and there are lots of Allegro 2000 aircraft flying without problem. Why not just leave the wiring as is?

If there is a charging issue, lets address that.

Let me know if I can help.

Jim Butcher


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hgmckay



Joined: 23 May 2006
Posts: 385

PostPosted: Tue Nov 27, 2018 10:14 am    Post subject: Rotax 912 UL Rectifier wiring Reply with quote

Jim, I agree. I don’t know why Lockwood’s article implies the other wires R, B+, and C are to be disconnected. I wish some one could explain that. I have a gut feeling my Rectifier is bad. I would like to send you a list of the electrical items (installed load) that is on my plane as well as what I think is the actual T.O. and Landing load demand to discuss that further; but I would like to discuss that directly with you rather than loading up the forum with a lot of back and forth dialogue. Could we do that directly by email? My email is hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net). Let me know.  

Hugh G. McKay III, P.E. Fellow. L.M. ASCE
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037

Ph. 704-661-8271
Fax 704-483-5466
Email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.geo.com (click on Power Division)
Sent from Mail for Windows 10

From: h&amp;jeuropa (butcher43(at)att.net)
Sent: Tuesday, November 27, 2018 12:04 PM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Rotax 912 UL Rectifier wiring


--> RotaxEngines-List message posted by: "h&amp;jeuropa" <butcher43(at)att.net>

Hugh,

After posting the above post, I was thinking, why add complexity.  The circuit from Allegro is in accordance with Rotax requirements and there are lots of Allegro 2000 aircraft flying without problem.  Why not just leave the wiring as is? 

If there is a charging issue, lets address that.

Let me know if I can help.

Jim Butcher




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