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asc23111964(at)hotmail.co
Guest

Posted: Sat Jan 11, 2014 1:48 pm Post subject: Ducati rectifier/regulators

Hi folks,

Andy Cullum here G-CGDH.

Could anybody give me some info on the latest thoughts on replacement of

The Ducati voltage regulator/rectifier as we think ours may have failed.

Any advice is gratefully received.

Best regards

Andy Cullum.



Sent from my iPhone

rowlandcarson(at)gmail.co
Guest

Posted: Sat Jan 11, 2014 2:12 pm Post subject: Ducati rectifier/regulators

On 11 Jan 2014, at 21:47, andrew cullum wrote:



 	  Quote: 	
		   Andy Cullum here G-CGDH.

 Could anybody give me some info on the latest thoughts on replacement of

 The Ducati voltage regulator/rectifier as we think ours may have failed.

 Any advice is gratefully received.


	


Andy - I bought the Schicke GR6 regulator



http://www.schicke-electronic.de/dgr3.htm



but I have not yet got to the stage of installing it in my Europa build. Despite the LAA standard mod SM12970 showing the supplier as Conair, I found they did not have any in stock ("there's no demand") and were uninterested in ordering one for me. However Herr Schicke was happy to deal direct with me in euros and communicates well in english. He doesn't do credit cards or paypal so I did an international bank transfer and that worked well although the bank fee for doing it was higher than one might have hoped!



I'm sure others are actually flying with the GR6 - but maybe not for longer than the mean-time-between-failure of the Ducati unit - so perhaps no-one can say yet if it's more long-lived.



BTW, before you ask, I already sold my Ducati unit!



Hope this is of some use.



in friendship



Rowland



| Rowland Carson          ... that's Rowland with a 'w' ...

| <rowlandcarson(at)gmail.com>            http://www.rowlandcarson.org.uk

| Skype, Twitter: rowland_carson      Facebook: Rowland Carson

| pictures: http://picasaweb.google.com/rowlandcarson

paul.the.aviator(at)gmail
Guest

Posted: Sat Jan 11, 2014 4:04 pm Post subject: Ducati rectifier/regulators

My Ducati lasted about 1100 hours / 9 years and I replaced it with a Schicke.  So far it has been working fine.

They are not available in the US so if you want one you will need a find soul in Europe to send it to you.

On Saturday, January 11, 2014, Rowland Carson  wrote:

[quote]--> Europa-List message posted by: Rowland Carson <[url=javascript:;]rowlandcarson(at)gmail.com[/url]>

 On 11 Jan 2014, at 21:47, andrew cullum wrote:

 > Andy Cullum here G-CGDH.

 > Could anybody give me some info on the latest thoughts on replacement of

 > The Ducati voltage regulator/rectifier as we think ours may have failed.

 > Any advice is gratefully received.

 Andy - I bought the Schicke GR6 regulator

 http://www.schicke-electronic.de/dgr3.htm

 but I have not yet got to the stage of installing it in my Europa build. Despite the LAA standard mod SM12970 showing the supplier as Conair, I found they did not have any in stock ("there's no demand") and were uninterested in ordering one for me. However Herr Schicke was happy to deal direct with me in euros and communicates well in english. He doesn't do credit cards or paypal so I did an international bank transfer and that worked well although the bank fee for doing it was higher than one might have hoped!

 I'm sure others are actually flying with the GR6 - but maybe not for longer than the mean-time-between-failure of the Ducati unit - so perhaps no-one can say yet if it's more long-lived.

 BTW, before you ask, I already sold my Ducati unit!

 Hope this is of some use.

 in friendship

 Rowland

 | Rowland Carson          ... that's Rowland with a 'w' ...

 | <[url=javascript:;]rowlandcarson(at)gmail.com[/url]>            http://www.rowlandcarson.org.uk

  | Skype, Twitter: rowland_carson      Facebook: Rowland Carson

 | pictures: http://picasaweb.google.com/rowlandcarson

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 [b]

Ivor Phillips

Joined: 16 Jan 2006
Posts: 253
Location: London UK

Posted: Sun Jan 12, 2014 1:52 am Post subject: Ducati rectifier/regulators

I have had the schicke since first flight 2008, it has worked flawlessly with a steady reading on the amp meter, not the rising and falling of the old Ducati unit that is gathering dust on a shelf,

ivor

G-IVER

Sent from my iPad

[quote] On 12 Jan 2014, at 00:03, Paul McAllister <paul.the.aviator(at)gmail.com> wrote:

 My Ducati lasted about 1100 hours / 9 years and I replaced it with a Schicke.  So far it has been working fine.

 They are not available in the US so if you want one you will need a find soul in Europe to send it to you.

> On Saturday, January 11, 2014, Rowland Carson wrote:

> 

> 

> On 11 Jan 2014, at 21:47, andrew cullum wrote:

> 

> > Andy Cullum here G-CGDH.

> > Could anybody give me some info on the latest thoughts on replacement of

> > The Ducati voltage regulator/rectifier as we think ours may have failed

Roland

Joined: 30 Nov 2009
Posts: 334
Location: EDLE

Posted: Wed Jan 15, 2014 10:33 am Post subject: Re: Ducati rectifier/regulators

Andy,



I threw the Ducati out for a Silent Hektik (charges 14,5 V). Works perfectly and is "plug and Play".



http://www.silent-hektik.com/UL_R_912.htm



Regards

Roland



PH-ZTI

XS Trigear 914

trevpond(at)aol.com
Guest

Posted: Thu Jan 16, 2014 6:46 am Post subject: Ducati rectifier/regulators

Hi Roland 



Did you buy it direct, and is there a mod number for it?



Regards



Trev

GLINN



Sent from my iPhone 



 	  Quote: 	
		   On 15 Jan 2014, at 18:33, "Roland" <schmidtroland(at)web.de> wrote:

 

 

 

 Andy,

 

 I threw the Ducati out for a Silent Hektik (charges 14,5 V). Works perfectly and is "plug and Play".

 

 http://www.silent-hektik.com/UL_R_912.htm

 

 Regards

 Roland

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=416951#416951

Roland

Joined: 30 Nov 2009
Posts: 334
Location: EDLE

Posted: Thu Jan 16, 2014 7:29 am Post subject: Re: Ducati rectifier/regulators

Hi Trev,

I bought it direct from Silent Hektik by order form



https://www.ssl-id.de/silent-hektik.de/SH_Best.php



(costs 197 EUR). No MOD number I'm afraid, although all SH-Products are of top quality. 

My aircraft is dutch registered.

Roland

PH-ZTI

XS Trigear 914

Trevpond(at)aol.com
Guest

Posted: Thu Jan 16, 2014 8:27 am Post subject: Ducati rectifier/regulators

Thanks Roland.

  

  In a message dated 16/01/2014 15:30:31 GMT Standard Time,  schmidtroland(at)web.de writes:

  	  Quote: 	
		  -->    Europa-List message posted by: "Roland" <schmidtroland(at)web.de>



Hi    Trev,

I bought it direct from Silent Hektik by order form (costs 197 EUR).    No MOD number I'm afraid, although all SH-Products are of top quality. 

My    aircraft is dutch registered.

Roland

PH-ZTI

XS Trigear    914





Read this topic online    here:



http://forums.matronics.com/viewtopic.php?p=417010#417010

	


 [quote][b]

steven.pitt2(at)ntlworld.
Guest

Posted: Fri Jan 17, 2014 8:41 am Post subject: Ducati rectifier/regulators

Trevor,

 The Schicke is a Club mod which you can find on the Club website under LAA  Standard mods. 

 Nigel Graham is looking after mods whilst Ian is recovering and if  Roland has had good experience with the SH it might be a candidate for a Mod.  However, I know that Tim Houlihan has recently fitted the Schicke and it was  quite a lot cheaper than the SH. I also have the Schicke and can support its  fitting as against the Ducati.

 Steve Pitt

 Chairman, Europa Club

 [quote]   ---

houlihan(at)blueyonder.co
Guest

Posted: Fri Jan 17, 2014 9:17 am Post subject: Ducati rectifier/regulators

I can confirm what Steve has said about the Schicke regulator. I purchased one last October directly from the manufacturer. I include a quote from an email from Schicke. my only comment would be that paying for it can be an issue as he does not accept payment by card or PayPal  He said "you can buy the GR6 directly from us. It will cost 92,- eur + transport to GB (18,-) + 19% VAT = 130,90 €Delivery after payment. Please send your address then we will send you a proforma invoice. with best regardsU. Schicke"

 

I noted that the regulator I fitted has much larger and more effective heatsink than the Ducatti and Mr Schicke advised me that the large capacitor is no longer required.

 



I expect both alternative devices will have better reliability than the original. The Silent hectic website is worth a study ! there are some interesting items there.

 



Tim

 



On 17 January 2014 16:40, Steven Pitt <steven.pitt2(at)ntlworld.com (steven.pitt2(at)ntlworld.com)> wrote:

 [quote]       Trevor,

 The Schicke is a Club mod which you can find on the Club website under LAA  Standard mods. 

 Nigel Graham is looking after mods whilst Ian is recovering and if  Roland has had good experience with the SH it might be a candidate for a Mod.  However, I know that Tim Houlihan has recently fitted the Schicke and it was  quite a lot cheaper than the SH. I also have the Schicke and can support its  fitting as against the Ducati.

 Steve Pitt

 Chairman, Europa Club

 [quote]   ---

Trevpond(at)aol.com
Guest

Posted: Fri Jan 17, 2014 12:37 pm Post subject: Ducati rectifier/regulators

Thanks Steve

  

  In a message dated 17/01/2014 16:42:20 GMT Standard Time,  steven.pitt2(at)ntlworld.com writes:

 [quote]   Trevor,

   The Schicke is a Club mod which you can find on the Club website under    LAA Standard mods. 

   Nigel Graham is looking after mods whilst Ian is recovering and if    Roland has had good experience with the SH it might be a candidate for a Mod.    However, I know that Tim Houlihan has recently fitted the Schicke and it was    quite a lot cheaper than the SH. I also have the Schicke and can support its    fitting as against the Ducati.

   Steve Pitt

   Chairman, Europa Club

   [quote]     ---

jan_de_jong(at)casema.nl
Guest

Posted: Mon Jan 20, 2014 8:28 am Post subject: Ducati rectifier/regulators

Re two-phase bridge rectifier/regulator.

The 2 thyristors in the rectifier bridge do not short the AC input or 

"dump" anything.

On the contrary, they disconnect the DC output from the AC input when 

the output voltage threatens to exceed the set voltage.

All output current passes through one branch of one diode and one 

thyristor in series half the time and through the other identical branch 

also half the time.

Heat development is proportional to the output current and the voltage 

drop across a branch.

Voltage drops increase somewhat with current, so heat development 

increases more than linearly with output current.

In the Ducati device the diode is reportedly a MR2510 pill (typically 

0.75V at 10A, 0.8V at 20A), the thyristor can be a 2N6504 (typically 

1.1V at 10A, 1.3V at 20A).

So at 10A the two branches of the bridge are each expected to generate 

0.5 x  (7.5 + 11) = 9.25W (total 18.5W) of heat.

And at 20A the two branches of the bridge are each expected to generate 

0.5 x (16 + 26) = 21W (total 42W) of heat.



(

a failure mode for the Ducati device is reportedly the loss of 

continuity of a diode pill attachment through thermal cycling; fitting 

external parallel diodes has been proposed as a solution; replacing the 

whole device seems more sensible

)



Cheers,

Jan de Jong

gregoryf.flyboy(at)comcas
Guest

Posted: Mon Jan 20, 2014 2:22 pm Post subject: Ducati rectifier/regulators

Respectfully, I believe that the circuit configuration that you are thinking

of is incorrect, Jan de Jong.



The SCR's do EXACTLY 'dump' the AC output DIRECTLY to ground. 

When one end of the thyristor connects to the alternating current output of

the coil, and the other end to ground...then that is all they can do but

short the AC output to ground. It is not acting as a PWM-like device at all,

simply a grounding device. Call it a direct-connect.

 

You mention heat. The direct-connect method is the best way to deal with the

heat. The forward voltage drop of the 'dumping' device is low, and the

current does not need to go through the diodes at all, which are

bypassed...hence your lowest heat output. 



Since the 'dumping device' connects the alternator output directly to

ground, without going through the diode, what is the power dissipated? While

in the dumping mode, lets say the current to dump was 10 amps(I'll use your

generously supplied information, so I don't have to look up specs) it would

be 1.1V * 10 amps. That's it.  11 watts. That is much better than the 18

Watts in your configuration.



 	  Quote: 	
		  (

a failure mode for the Ducati device is reportedly the loss of continuity

of a diode pill attachment through thermal >cycling; fitting external
	


parallel diodes has been proposed as a solution; replacing the whole device

seems more 

 	  Quote: 	
		  sensible

)


	


Well, maybe so!  However, if the failure mode is a loss in continuity, that

would mean the diodes are opening. That would also mean that connecting the

external diodes to the regulator would bring it back to life!



Regards,

Greg



--

jan_de_jong(at)casema.nl
Guest

Posted: Tue Jan 21, 2014 4:59 am Post subject: Ducati rectifier/regulators

Equally respectfully - "dumping to ground" is not dumping, but 

connection to the negative DC output terminal.

I attach a little OpenOffice drawing that hopefully clarifies (I hope 

that works).

Regards,

Jan

On 1/20/2014 11:21 PM, Greg Fuchs wrote:

[quote] 

 Respectfully, I believe that the circuit configuration that you are thinking

 of is incorrect, Jan de Jong.

 The SCR's do EXACTLY 'dump' the AC output DIRECTLY to ground.

 When one end of the thyristor connects to the alternating current output of

 the coil, and the other end to ground...then that is all they can do but

 short the AC output to ground. It is not acting as a PWM-like device at all,

 simply a grounding device. Call it a direct-connect.

 You mention heat. The direct-connect method is the best way to deal with the

 heat. The forward voltage drop of the 'dumping' device is low, and the

 current does not need to go through the diodes at all, which are

 bypassed...hence your lowest heat output.

 Since the 'dumping device' connects the alternator output directly to

 ground, without going through the diode, what is the power dissipated? While

 in the dumping mode, lets say the current to dump was 10 amps(I'll use your

 generously supplied information, so I don't have to look up specs) it would

 be 1.1V * 10 amps. That's it.  11 watts. That is much better than the 18

 Watts in your configuration.

> (

> a failure mode for the Ducati device is reportedly the loss of continuity

 of a diode pill attachment through thermal >cycling; fitting external

 parallel diodes has been proposed as a solution; replacing the whole device

 seems more

> sensible

> )

 Well, maybe so!  However, if the failure mode is a loss in continuity, that

 would mean the diodes are opening. That would also mean that connecting the

 external diodes to the regulator would bring it back to life!

 Regards,

 Greg

 --

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max8992

Joined: 28 Jul 2011
Posts: 142

Posted: Tue Jan 21, 2014 6:00 am Post subject: Ducati rectifier/regulators

Hi There,

Excuse my french but as far as I remember from my initial training in

electronics (in the 70's) a bridge of diodes will transform AC

input(sinusoidal signal) in semi-sinusoid output which will be "transformed"

in DC voltage by the action of a capacity. That DC output will be

proportional in value to the input which is itself proportional to value of

RPM of the alternator and to the consumption. At the output of the bridge is

the input of the regulator which will act to maintain  constant its own DC

output, more precisely to regulator the output DC current so that the output

DC voltage is at a standard level defined to have the battery correctly

charged ie 14.5V for the SH and 13.8V for the Ducati.

My two cents

Max  Cointe

mcointe(at)free.fr

F-PMLH Europa XS_TriGear

Kit #560-2003 912ULS/AirmasterAP332 490 hours

F-PLDJ Dyn’Aéro MCR 4S 

Kit #27-2002 912ULSFR/MTProp MTV7A 1600 heures

-----Message d'origine-----

De : owner-europa-list-server(at)matronics.com

[mailto:owner-europa-list-server(at)matronics.com] De la part de Jan de Jong

Envoyé : mardi 21 janvier 2014 13:59

À : europa-list(at)matronics.com

Objet : Re: Re: Ducati rectifier/regulators

Equally respectfully - "dumping to ground" is not dumping, but connection to

the negative DC output terminal.

I attach a little OpenOffice drawing that hopefully clarifies (I hope that

works).

Regards,

Jan

On 1/20/2014 11:21 PM, Greg Fuchs wrote:

 	  Quote: 	

 --> <gregoryf.flyboy(at)comcast.net>

 Respectfully, I believe that the circuit configuration that you are 

 thinking of is incorrect, Jan de Jong.

 The SCR's do EXACTLY 'dump' the AC output DIRECTLY to ground.

 When one end of the thyristor connects to the alternating current 

 output of the coil, and the other end to ground...then that is all 

 they can do but short the AC output to ground. It is not acting as a 

 PWM-like device at all, simply a grounding device. Call it a

direct-connect.

 	  Quote: 	

 You mention heat. The direct-connect method is the best way to deal 

 with the heat. The forward voltage drop of the 'dumping' device is 

 low, and the current does not need to go through the diodes at all, 

 which are bypassed...hence your lowest heat output.

 Since the 'dumping device' connects the alternator output directly to 

 ground, without going through the diode, what is the power dissipated? 

 While in the dumping mode, lets say the current to dump was 10 

 amps(I'll use your generously supplied information, so I don't have to 

 look up specs) it would be 1.1V * 10 amps. That's it.  11 watts. That 

 is much better than the 18 Watts in your configuration.

> (

> a failure mode for the Ducati device is reportedly the loss of 

> continuity

 of a diode pill attachment through thermal >cycling; fitting external 

 parallel diodes has been proposed as a solution; replacing the whole 

 device seems more

> sensible

> )

 Well, maybe so!  However, if the failure mode is a loss in continuity, 

 that would mean the diodes are opening. That would also mean that 

 connecting the external diodes to the regulator would bring it back to

life!

[quote]

 Regards,

 Greg

 --

_________________
Max8992
Europa XS #560 F-PMLH

jan_de_jong(at)casema.nl
Guest

Posted: Tue Jan 21, 2014 7:37 am Post subject: Ducati rectifier/regulators

It is called a rectifier-regulator because the rectifier (the bridge) 

also does the regulating; there is no separate regulating stage.

Two of the four diodes of the bridge are replaced by a diode-cum-switch 

(a thyristor) to make that possible.

At the beginning of a phase the thyristor in the conducting branch does 

not conduct.

The switch control function switches the thyristor on with a delay that 

depends on input AC voltage (RPM) and output DC current (load).

It increases / decreases the delay when the (average) output DC voltage 

is too high / too low.

The delay would probably be best controlled in terms of phase angle but 

in practice is most likely done in terms of time.

https://en.wikipedia.org/wiki/Rectifier has a nice animation half way 

the page.

The DC-output is extremely noisy - more than14V peak-to-peak for a 14V 

DC average output. A large capacitor across the DC output terminals is 

generally prescribed.



Regards,

Jan

On 1/21/2014 2:59 PM, Max Cointe (Free) wrote:

[quote] 



 Hi There,



 Excuse my french but as far as I remember from my initial training in

 electronics (in the 70's) a bridge of diodes will transform AC

 input(sinusoidal signal) in semi-sinusoid output which will be "transformed"

 in DC voltage by the action of a capacity. That DC output will be

 proportional in value to the input which is itself proportional to value of

 RPM of the alternator and to the consumption. At the output of the bridge is

 the input of the regulator which will act to maintain  constant its own DC

 output, more precisely to regulator the output DC current so that the output

 DC voltage is at a standard level defined to have the battery correctly

 charged ie 14.5V for the SH and 13.8V for the Ducati.

 My two cents



 Max  Cointe

 mcointe(at)free.fr

 F-PMLH Europa XS_TriGear

 Kit #560-2003 912ULS/AirmasterAP332 490 hours



 F-PLDJ Dyn’Aéro MCR 4S

 Kit #27-2002 912ULSFR/MTProp MTV7A 1600 heures

 -----Message d'origine-----

 De : owner-europa-list-server(at)matronics.com

 [mailto:owner-europa-list-server(at)matronics.com] De la part de Jan de Jong

 Envoyé : mardi 21 janvier 2014 13:59

 À : europa-list(at)matronics.com

 Objet : Re: Re: Ducati rectifier/regulators



 Equally respectfully - "dumping to ground" is not dumping, but connection to

 the negative DC output terminal.

 I attach a little OpenOffice drawing that hopefully clarifies (I hope that

 works).



 Regards,

 Jan



 On 1/20/2014 11:21 PM, Greg Fuchs wrote:

> 

> --> <gregoryf.flyboy(at)comcast.net>

>

> Respectfully, I believe that the circuit configuration that you are

> thinking of is incorrect, Jan de Jong.

>

> The SCR's do EXACTLY 'dump' the AC output DIRECTLY to ground.

> When one end of the thyristor connects to the alternating current

> output of the coil, and the other end to ground...then that is all

> they can do but short the AC output to ground. It is not acting as a

> PWM-like device at all, simply a grounding device. Call it a

 direct-connect.

>    

> You mention heat. The direct-connect method is the best way to deal

> with the heat. The forward voltage drop of the 'dumping' device is

> low, and the current does not need to go through the diodes at all,

> which are bypassed...hence your lowest heat output.

>

> Since the 'dumping device' connects the alternator output directly to

> ground, without going through the diode, what is the power dissipated?

> While in the dumping mode, lets say the current to dump was 10

> amps(I'll use your generously supplied information, so I don't have to

> look up specs) it would be 1.1V * 10 amps. That's it.  11 watts. That

> is much better than the 18 Watts in your configuration.

>

>> (

>> a failure mode for the Ducati device is reportedly the loss of

>> continuity

> of a diode pill attachment through thermal >cycling; fitting external

> parallel diodes has been proposed as a solution; replacing the whole

> device seems more

>> sensible

>> )

> Well, maybe so!  However, if the failure mode is a loss in continuity,

> that would mean the diodes are opening. That would also mean that

> connecting the external diodes to the regulator would bring it back to

 life!

> Regards,

> Greg

>

> --

gregoryf.flyboy(at)comcas
Guest

Posted: Tue Jan 21, 2014 9:31 am Post subject: Ducati rectifier/regulators

Well, since the generator is not a two-legged 'phi' connection (i.e. the

midpoint of the generator coil connected to the ground of the system or

vehicle, then 'dumping to ground' may not be the term to use after all. Yes,

I think that is correct.



Here are the two main failure modes of the Ducatti regulator as I see it.. 



A) If the aircraft has a very low load usage (i.e. no lights, no

instruments, etc.), the scr's are stressed and 'may' fail eventually. If

this happens, the Ducatti is unrecoverable.



B) If the aircraft has a very high load usage (using up most of its 15-18

amps), the output diodes are stressed and probably will fail eventually,

which is backed up by historical data gathering (they fail a lot at high

loads per many forum users). The Ducatti would then be recoverable by

placing 25 Amp or higher diodes on the external terminals as referenced

earlier.



Scenario (A) is unlikely, since everyone likes power-hungry instruments and

the like, where scenario (B) is the most likely for the same reason.



Thus, if someone wants to 'beef up' their ducatti, then they have the option

to place the external diodes. I guess it doesn't matter what kind, as long

as they can withstand the current from the generator. They will either help

the internal diodes survive almost forever, or take over for them when they

fail (It depends on the turn-on points between the internal and external

diodes).



Jan, do you agree with this?



Best Regards,

Greg



--

jan_de_jong(at)casema.nl
Guest

Posted: Tue Jan 21, 2014 12:03 pm Post subject: Ducati rectifier/regulators

ad A:

Don't agree. The only stress would be somewhat higher reverse voltage. 

The Ducati R/R is not a shunt regulator.



ad B:

Agree, but the thyristors are more stressed than the diodes. They drop a 

little more voltage and dissipate more heat.

On the other hand, the custom fitting of the diode pills could be more 

uncertain than the standard fitting of the thyristors (TO220 I believe).



Parallelling the diodes with external ones is possible. They would 

require a heat sink. Are the failure statistics clear about the diodes?

I think it would be better to get an R/R without issues.



Regards,

Jan

On 1/21/2014 6:30 PM, Greg Fuchs wrote:

[quote] 



 Well, since the generator is not a two-legged 'phi' connection (i.e. the

 midpoint of the generator coil connected to the ground of the system or

 vehicle, then 'dumping to ground' may not be the term to use after all. Yes,

 I think that is correct.



 Here are the two main failure modes of the Ducatti regulator as I see it..



 A) If the aircraft has a very low load usage (i.e. no lights, no

 instruments, etc.), the scr's are stressed and 'may' fail eventually. If

 this happens, the Ducatti is unrecoverable.



 B) If the aircraft has a very high load usage (using up most of its 15-18

 amps), the output diodes are stressed and probably will fail eventually,

 which is backed up by historical data gathering (they fail a lot at high

 loads per many forum users). The Ducatti would then be recoverable by

 placing 25 Amp or higher diodes on the external terminals as referenced

 earlier.



 Scenario (A) is unlikely, since everyone likes power-hungry instruments and

 the like, where scenario (B) is the most likely for the same reason.



 Thus, if someone wants to 'beef up' their ducatti, then they have the option

 to place the external diodes. I guess it doesn't matter what kind, as long

 as they can withstand the current from the generator. They will either help

 the internal diodes survive almost forever, or take over for them when they

 fail (It depends on the turn-on points between the internal and external

 diodes).



 Jan, do you agree with this?



 Best Regards,

 Greg



 --

europa10(at)bellsouth.net
Guest

Posted: Tue Jan 21, 2014 1:13 pm Post subject: Ducati rectifier/regulators

As info.....

I opened up one of the Rotax regulators a friend gave me after a 

failure.  The two diodes were bad and were open so paralleling them with 

external diodes does seem to be a viable option. Relatively cheap for 

the cost of the diodes and a heat sink.  No modification to the existing 

regulator required.  Attached is the fix I obtained from another 

website.  Just need to join the diodes to the B and two G terminals.

Just my two cents worth.....

Bill

A010 Classic Monowheel

Still building.

On 1/21/2014 3:02 PM, Jan de Jong wrote:

[quote] 

 ad A:

 Don't agree. The only stress would be somewhat higher reverse voltage. 

 The Ducati R/R is not a shunt regulator.

 ad B:

 Agree, but the thyristors are more stressed than the diodes. They drop 

 a little more voltage and dissipate more heat.

 On the other hand, the custom fitting of the diode pills could be more 

 uncertain than the standard fitting of the thyristors (TO220 I believe).

 Parallelling the diodes with external ones is possible. They would 

 require a heat sink. Are the failure statistics clear about the diodes?

 I think it would be better to get an R/R without issues.

 Regards,

 Jan

 On 1/21/2014 6:30 PM, Greg Fuchs wrote:

> 

> <gregoryf.flyboy(at)comcast.net>

>

> Well, since the generator is not a two-legged 'phi' connection (i.e. the

> midpoint of the generator coil connected to the ground of the system or

> vehicle, then 'dumping to ground' may not be the term to use after 

> all. Yes,

> I think that is correct.

>

> Here are the two main failure modes of the Ducatti regulator as I see 

> it..

>

> A) If the aircraft has a very low load usage (i.e. no lights, no

> instruments, etc.), the scr's are stressed and 'may' fail eventually. If

> this happens, the Ducatti is unrecoverable.

>

> B) If the aircraft has a very high load usage (using up most of its 

> 15-18

> amps), the output diodes are stressed and probably will fail eventually,

> which is backed up by historical data gathering (they fail a lot at high

> loads per many forum users). The Ducatti would then be recoverable by

> placing 25 Amp or higher diodes on the external terminals as referenced

> earlier.

>

> Scenario (A) is unlikely, since everyone likes power-hungry 

> instruments and

> the like, where scenario (B) is the most likely for the same reason.

>

> Thus, if someone wants to 'beef up' their ducatti, then they have the 

> option

> to place the external diodes. I guess it doesn't matter what kind, as 

> long

> as they can withstand the current from the generator. They will 

> either help

> the internal diodes survive almost forever, or take over for them 

> when they

> fail (It depends on the turn-on points between the internal and external

> diodes).

>

> Jan, do you agree with this?

>

> Best Regards,

> Greg

>

> --

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peterz(at)zutrasoft.com
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Posted: Tue Jan 21, 2014 1:43 pm Post subject: Ducati rectifier/regulators

 	  Quote: 	
		  From that schematic, it is indeed a simple waste/dump regulator,with the two failing diodes being there to prevent battery from reverse feeding during the dumps.  It is pretty silly that they undersized them for rated alternator generating current capacity.  "Certified". Wow.


	


Cheers,

Pete



[quote] On Jan 21, 2014, at 4:12 PM, Bill Henderson <europa10(at)bellsouth.net> wrote:

 

 As info.....

 

 I opened up one of the Rotax regulators a friend gave me after a failure.  The two diodes were bad and were open so paralleling them with external diodes does seem to be a viable option. Relatively cheap for the cost of the diodes and a heat sink.  No modification to the existing regulator required.  Attached is the fix I obtained from another website.  Just need to join the diodes to the B and two G terminals.

 

 Just my two cents worth.....

 

 Bill

 A010 Classic Monowheel

 Still building.

 

 

 

 

> On 1/21/2014 3:02 PM, Jan de Jong wrote:

> 

> 

> 

> ad A:

> Don't agree. The only stress would be somewhat higher reverse voltage. The Ducati R/R is not a shunt regulator.

> 

> ad B:

> Agree, but the thyristors are more stressed than the diodes. They drop a little more voltage and dissipate more heat.

> On the other hand, the custom fitting of the diode pills could be more uncertain than the standard fitting of the thyristors (TO220 I believe).

> 

> Parallelling the diodes with external ones is possible. They would require a heat sink. Are the failure statistics clear about the diodes?

> I think it would be better to get an R/R without issues.

> 

> Regards,

> Jan

> 

> 

>> On 1/21/2014 6:30 PM, Greg Fuchs wrote:

>> 

>> 

>> 

>> 

>> Well, since the generator is not a two-legged 'phi' connection (i.e. the

>> midpoint of the generator coil connected to the ground of the system or

>> vehicle, then 'dumping to ground' may not be the term to use after all. Yes,

>> I think that is correct.

>> 

>> Here are the two main failure modes of the Ducatti regulator as I see it..

>> 

>> A) If the aircraft has a very low load usage (i.e. no lights, no

>> instruments, etc.), the scr's are stressed and 'may' fail eventually. If

>> this happens, the Ducatti is unrecoverable.

>> 

>> B) If the aircraft has a very high load usage (using up most of its 15-18

>> amps), the output diodes are stressed and probably will fail eventually,

>> which is backed up by historical data gathering (they fail a lot at high

>> loads per many forum users). The Ducatti would then be recoverable by

>> placing 25 Amp or higher diodes on the external terminals as referenced

>> earlier.

>> 

>> Scenario (A) is unlikely, since everyone likes power-hungry instruments and

>> the like, where scenario (B) is the most likely for the same reason.

>> 

>> Thus, if someone wants to 'beef up' their ducatti, then they have the option

>> to place the external diodes. I guess it doesn't matter what kind, as long

>> as they can withstand the current from the generator. They will either help

>> the internal diodes survive almost forever, or take over for them when they

>> fail (It depends on the turn-on points between the internal and external

>> diodes).

>> 

>> Jan, do you agree with this?

>> 

>> Best Regards,

>> Greg

>> 

>> --

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