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914 Alternator Options

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N6ZY

Joined: 08 Aug 2011
Posts: 31

Posted: Fri Aug 02, 2013 9:55 am Post subject: 914 Alternator Options

I am building a Europa with a Rotax 914 engine.  It has become clear to me that my electrical power needs are unlikely to be met from the internal alternator.  The alternatives are the Rotax belt driven alternator, or the B&C SD20 alternator driven off the vacuum pad. The belt driven alternator goes where I would really like my air intake hoses to go, so the SD20 looks like an attractive option.  However when I look at my vacuum pad, it has a blanking plate, so I assume that I would have to install the vacuum drive gear shaft.  Is this correct and can anyone advise me as to how difficult this is?  Is it something that I can do myself or, as it seems to require opening the gearbox, is this a Rotax service center job?  Thanks.



Jerry Fisher

Gilles.Thesee(at)ac-greno
Guest

Posted: Fri Aug 02, 2013 10:09 am Post subject: 914 Alternator Options

N6ZY a écrit :

 	  Quote: 	
		   



 I am building a Europa with a Rotax 914 engine.  It has become clear to me that my electrical power needs are unlikely to be met from the internal alternator.  The alternatives are the Rotax belt driven alternator, or the B&C SD20 alternator driven off the vacuum pad. The belt driven alternator goes where I would really like my air intake hoses to go, so the SD20 looks like an attractive option.  However when I look at my vacuum pad, it has a blanking plate, so I assume that I would have to install the vacuum drive gear shaft.  Is this correct and can anyone advise me as to how difficult this is?  Is it something that I can do myself or, as it seems to require opening the gearbox, is this a Rotax service center job?  Thanks.



   


	


Jerry,



Have you considered this option ?



http://contrails.free.fr/elec_second_alternateur.php



Best regards,

-- 

Gilles

http://contrails.free.fr

jan_de_jong(at)casema.nl
Guest

Posted: Fri Aug 02, 2013 12:44 pm Post subject: 914 Alternator Options

And there is this:

http://www.flygas.info/en/kit-double-alternator-for-rotax.html

Better as a 10A backup than additional power it seems to me.



Jan de Jong



On 8/2/2013 8:09 PM, Gilles Thesee wrote:

 	  Quote: 	
		   

 <Gilles.Thesee(at)ac-grenoble.fr>



 N6ZY a écrit :

> 

>

> I am building a Europa with a Rotax 914 engine.  It has become clear 

> to me that my electrical power needs are unlikely to be met from the 

> internal alternator.  The alternatives are the Rotax belt driven 

> alternator, or the B&C SD20 alternator driven off the vacuum pad. The 

> belt driven alternator goes where I would really like my air intake 

> hoses to go, so the SD20 looks like an attractive option.  However 

> when I look at my vacuum pad, it has a blanking plate, so I assume 

> that I would have to install the vacuum drive gear shaft.  Is this 

> correct and can anyone advise me as to how difficult this is?  Is it 

> something that I can do myself or, as it seems to require opening the 

> gearbox, is this a Rotax service center job?  Thanks.

>



 Jerry,



 Have you considered this option ?



 http://contrails.free.fr/elec_second_alternateur.php



 Best regards,

ploucandco

Joined: 16 Sep 2007
Posts: 69

Posted: Sat Aug 03, 2013 10:04 am Post subject: Re: 914 Alternator Options

Jerry, to answer your specific question about opening the ROTAX gearbox to install an alternator on the vacuum pad, I consider it to be the work of a ROTAX specilised mechanic. Nothing really complex, but this is not really easy to open the gearbox if you don't have the right tools and don't know how to do (have followed the ROTAX maintenance course).



Concerning adding an extra alternator, I have myself a 914 powered Europa. I added an alternator on the crankshaft based on Jim Butcher informations (see the link from Gilles). That works very well.



In fact, you have the following options:

- extra alternator of ROTAX is NOK as doesn't fit under the Europa cowling. 

- 20A B&C on the is a good option but adds weight and you need to open the gearbox. The added weight is fully in the front, that just add on top of your airmaster (I would expect that you use a good constant speed prop with a 914). Also 20A extra could be limited if you have a 2 axis AP, lights, a decent panel and a pitot heater...

- 40/60A B&C on the crankshaft is the way to go if you are consuming much power and are not willing to be dependable on the ROTAX/DUCATI. regulator. It is a bit heavy but works very well. Well, if you have your engine already installed, this is not really easy to install the whole setup

- the flygas solution that Jan mentioned was also on my short list but I removed it based on cost (around 1000EUR) and the low output power 10-14A.

- ROTAX 912is second alternator on the crankshaft. This is a solution similar to the one of flygas but coming directly from ROTAX. The output is about 30A from 2000RPM. Don't know about price (likely not cheap, but ROTAX quality), but that would be my prefered solution if I had to do it again today.  You can find more infos in the 912is illustrated part catalog: http://www.flyrotax.com/portaldata/5/dokus/d05447.pdf and the 912is installation manual http://www.flyrotax.com/portaldata/5/dokus/d05455.pdf



Hope this helps, Jacques.

ploucandco

Joined: 16 Sep 2007
Posts: 69

Posted: Sat Aug 03, 2013 10:37 am Post subject: Re: 914 Alternator Options

Well, I just reviewed the 912is part catalog and I found out that you need to replace the whole original generator setup of the 914 with a new one from the 912is to get 2 generators and 2 regulators. As this is also where you have the pick-up coils, I would think that it is way more difficult than what I first thought. So it was an interesting idea but not really feasible as it seems.



Jacques.

jan_de_jong(at)casema.nl
Guest

Posted: Sat Aug 03, 2013 11:02 am Post subject: 914 Alternator Options

Hi Jacques.



The 912iS alternator is oil cooled and needs the 912iS engine block, so 

that option seems definitely out.



Jan de Jong

h&jeuropa

Joined: 07 Nov 2006
Posts: 645

Posted: Fri Aug 09, 2013 4:44 am Post subject: Re: 914 Alternator Options

Jerry



Our 914 Europa has dual GRT EFIS, GRT EIS, GNS430, GMA340 & GTX327.  Also AeroLED pos & strobes.  914 so TCU & fuel pumps.  Typically we see about 8-10 amps load.  The Rotax alt handles this with ease.  There is a simple mod for the Ducatti regulator to address it's potential failure but if you make sure it is cool, it works fine at 10 amps.



We originally had a B&C 60 amp alt driven off the rear of the engine.  There is a photo earlier in this thread.  The coupling failed after 250 hours and we decided to try just the Rotax alt.  So far another 250 hours and no problems.  We did replace the original Whelan lights with AeroLED when we swapped.  The Whelans draw a lot of current.



I'd suggest try just the Rotax alt.  You can always add a B&C pad mount.  



If you take off the blanking plate you may discover you have a vac pump drive already.  If not, it is easy to add, only requires removal of the gearbox.  Lockwood shows a retrofit package for $750.  You can do it yourself or send out the gearbox.



Hope this helps.



Jim Butcher

N241BW

475 hours and loving it!

rparigoris

Joined: 24 Nov 2009
Posts: 792

Posted: Fri Aug 09, 2013 7:13 am Post subject: 914 Alternator Options

Hi Jim 

 	"There is a simple mod for the Ducatti regulator to address it's potential failure" 

 	Can you provide any more information on this mod? 

 	Thx. 

 	Ron Parigoris 

 	  

 	     [quote][b]

h&jeuropa

Joined: 07 Nov 2006
Posts: 645

Posted: Fri Aug 09, 2013 11:47 am Post subject: Re: 914 Alternator Options

Ron,



Supposedly the failure occurs when the regulator gets hot.  If you look at a schematic of the regulator, it is a bridge rectifier with two SCR and two diodes.  Supposedly, the diodes are poorly mounted from a thermal point of view and that is what fails.  The solution is to put two external diodes in parallel with the originals.  This can be done by connecting them between the yellow wires and R.  I'm away from my data but I found a bridge to do this.  A bridge is better than diodes because it provides a mounting surface that is not at R voltage.



I have not incorporated this but have the parts and will do this Fall.



I can email you the PN of the bridge later if you wish.



Jim

rparigoris

Joined: 24 Nov 2009
Posts: 792

Posted: Fri Aug 09, 2013 12:56 pm Post subject: 914 Alternator Options

Hi Jim 

 	Yes please E-Mail info. 

 	I plan on adding a diode in series with the sense wire to raise the voltage of the regulator. 14.2 to 14.4 is what Odyssey is happy seeing, Ducati is set way low. 

 	Ron P. 

 	  

 	> --> RotaxEngines-List message posted by: "h&amp;jeuropa" 	> <butcher43(at)att.net> 	> 	> Ron, 	> 	> Supposedly the failure occurs when the regulator gets hot. If you look at 	> a schematic of the regulator, it is a bridge rectifier with two SCR and 	> two diodes. Supposedly, the diodes are poorly mounted from a thermal 	> point of view and that is what fails. The solution is to put two external 	> diodes in parallel with the originals. This can be done by connecting 	> them between the yellow wires and R. I'm away from my data but I found a 	> bridge to do this. A bridge is better than diodes because it provides a 	> mounting surface that is not at R voltage. 	> 	> I have not incorporated this but have the parts and will do this Fall. 	> 	> I can email you the PN of the bridge later if you wish. 	> 	> Jim 	> 	> 	> 	> 	> Read this topic online here: 	> 	> http://forums.matronics.com/viewtopic.php?p=406365#406365 	> 	> 	> 	> 	> 	> 	> 	> 	> 	> 	>    [quote][b]

N6ZY

Joined: 08 Aug 2011
Posts: 31

Posted: Sun Aug 11, 2013 7:37 am Post subject: Re: 914 Alternator Options

Thanks to all who responded to my original post about Rotax alternators.  I think that I will try using just the Rotax generator at first.  I was put off by the Rotax statement that the fuel pumps etc can take up to 8 amps, but it appears that this is too pessimistic.  Jim, your set up sounds very similar to mine.  Have you also fitted an autopilot, as these can take quite a bit of power when operating?



I would also be interested in the diode mod to the Ducatti regulator.  Could you please either post it here, or email it to me?  I will probably cover the regulator  with a cooling shroud as well.



Jerry

klinefelter.kevin(at)gmai
Guest

Posted: Sun Aug 11, 2013 9:27 am Post subject: 914 Alternator Options

Consider mounting the regulator on the passenger footwell front, inside the plenum for the air filter. Should stay nice and cool in there.

Kevin



On Aug 11, 2013, at 8:37 AM, "N6ZY" <jffisher(at)gmail.com> wrote:



 	  Quote: 	
		   

 

 Thanks to all who responded to my original post about Rotax alternators.  I think that I will try using just the Rotax generator at first.  I was put off by the Rotax statement that the fuel pumps etc can take up to 8 amps, but it appears that this is too pessimistic.  Jim, your set up sounds very similar to mine.  Have you also fitted an autopilot, as these can take quite a bit of power when operating?

 

 I would also be interested in the diode mod to the Ducatti regulator.  Could you please either post it here, or email it to me?  I will probably cover the regulator  with a cooling shroud as well.

 

 Jerry

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=406447#406447

h&jeuropa

Joined: 07 Nov 2006
Posts: 645

Posted: Wed Aug 14, 2013 5:30 am Post subject: Re: 914 Alternator Options

The bridge I selected is a 36MB120A, 35A 1200V bridge.  It needs to mount on a heat sink.  Wakefield 403K fits nicely.  Both available from Newark Electronics.  



Jerry - I noticed on the GRT website that their two servos are powered from a 2.5 amp supply.  I certainly have 2.5A available on my 914 Europa.



Jim Butcher

N241BW

rparigoris

Joined: 24 Nov 2009
Posts: 792

Posted: Wed Aug 14, 2013 9:27 am Post subject: 914 Alternator Options

Hi Jim 

 	Thx. for providing us with the bridge information for 914 regulator: 

 	"I selected is a 36MB120A, 35A 1200V bridge. It needs to mount on a heat sink. Wakefield 403K fits nicely. Both available from Newark Electronics." 

 	Ron Parigoris 	     [quote][b]

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