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kenryan
Joined: 20 Oct 2009
Posts: 424
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 Posted: Thu Jan 21, 2016 9:04 pm Post subject: Rotax 914 Generator, Alternator, Starting and Fuel Pump Con |
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Thanks Joe for your comments. Here are my comments on your comments:
1. In case of over voltage the 5 amp fuse will blow before the 5 amp breaker. Eliminate the fuse.
Okay, I didn't think of this. My "Bus" is a fuseblock so there is automatically a fuse associated with each circuit. Maybe I could put a 10 amp fuse in there, and then keep the 5 amp breaker for overvoltage protection? The alternative would be to break this circuit out of the fuseblock. Seems easier to just use a larger fuse.
2. The note on the drawing says that the main bus can be separated from the battery. If that means to shut off the master, I do not know why anyone would want to do that.
Simple answer--smoke in the cockpit. In that case the #1 priority is to try to stop the fire. First step, shut down all the electric not necessary to keep the engine running. Hit the master, which opens the battery relay, which shuts down all the circuits except the main fuel pump.
3. I suggest adding a relay and lamp to indicate that the 20 amp dynamo is not working.
I have Dynon Skyview with the ability to monitor two voltage sources. I would think this would be sufficient to monitor the health of the 20 amp integrated generator.
4. When the momentary push button switch is first pressed, the 5 amp fuse will carry current to fuel pump #1 before the
rectifier/regulator puts out full voltage.
I didn't think of this either. I should make that a 10 amp fuse. Five amps would "probably" work but it is too close to the edge for a critical component.
5. Resize the rectifier/regulator fuse from 20 amps to whateverthe pump requires. 10 amps?
On that circuit I am showing a 5 amp fuse at the bus and a 20 amp circuit breaker on the panel. We have already agreed (in #4 above) that the fuse should be 10 amp. The 20 amp breaker is really only there to give me a way to shut down the integrated generator if necessary. Is there any good reason it should be 10 amp instead of 20 amp? Seems like either one would be fine.
Thanks for your comments. Hope you follow up, and hope others will chime in too.
On Thu, Jan 21, 2016 at 7:12 PM, user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:
| Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
In case of over voltage the 5 amp fuse will blow before the 5
amp breaker. Eliminate the fuse.
The note on the drawing says that the main bus can be separated
from the battery. If that means to shut off the master, I do
not know why anyone would want to do that.
I suggest adding a relay and lamp to indicate that the 20 amp
dynamo is not working. Red lamp should go out when
rectifier/regulator is working. See attached pdf.
When the momentary push button switch is first pressed, the 5
amp fuse will carry current to fuel pump #1 before the
rectifier/regulator puts out full voltage. That fuse could
blow if not rated to handle the fuel pump current.
Resize the rectifier/regulator fuse from 20 amps to whatever
the pump requires. 10 amps?
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=452186#452186
Attachments:
http://forums.matronics.com//files/rotax_914_pump_138.pdf
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user9253
Joined: 28 Mar 2008
Posts: 1908
Location: Riley TWP Michigan
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| Posted: Fri Jan 22, 2016 7:01 am Post subject: Re: Rotax 914 Generator, Alternator, Starting and Fuel Pump |
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1. Over voltage protection.
Bob Nuckolls made a demonstration board for an court trial. He made a movie showing what happens when fuses or circuit breakers are in series. If Bob is reading, maybe he can provide a link to that movie. It was interesting. Anyway, even a 10 amp fuse might blow before a 5 amp series breaker trips. The fuse needs to be slow blow and much larger than the circuit breaker. Or do not put protection devices in series.
2. Understand
3. The capabilities of an EFIS are amazing.
4. OK
5. The reason that I suggested using a smaller breaker for the output of the 20 amp dynamo is that in the event of a short circuit, a 20 amp breaker might not ever trip because the dynamo will struggle to put out that much current. The AC coils or regulator could overheat. Since the fuel pump is the only load and requires less than 10 amps, a larger breaker is not needed.
Have fun with your project.
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kenryan
Joined: 20 Oct 2009
Posts: 424
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| Posted: Fri Jan 22, 2016 8:43 am Post subject: Rotax 914 Generator, Alternator, Starting and Fuel Pump Con |
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Thanks Joe. I will move the field wire for the 40 amp alternator away from the bus, maybe to the battery relay. That will eliminate the fuse, leaving only the 5 amp panel breaker on the over voltage/field circuit. I will downsize the 20 amp panel breaker for the 20 amp integrated generator to 10 amps for the reasons you stated.
On Fri, Jan 22, 2016 at 6:01 AM, user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:
| Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
1. Over voltage protection.
Bob Nuckolls made a demonstration board for an court trial. He made a movie showing what happens when fuses or circuit breakers are in series. If Bob is reading, maybe he can provide a link to that movie. It was interesting. Anyway, even a 10 amp fuse might blow before a 5 amp series breaker trips. The fuse needs to be slow blow and much larger than the circuit breaker. Or do not put protection devices in series.
2. Understand
3. The capabilities of an EFIS are amazing.
4. OK
5. The reason that I suggested using a smaller breaker for the output of the 20 amp dynamo is that in the event of a short circuit, a 20 amp breaker might not ever trip because the dynamo will struggle to put out that much current. The AC coils or regulator could overheat. Since the fuel pump is the only load and requires less than 10 amps, a larger breaker is not needed.
Have fun with your project.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=452191#452191
===========
br> fts!)
r> > w.buildersbooks.com" rel="noreferrer" target="_blank">www.buildersbooks.com
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
-Matt Dralle, List Admin.
===========
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Electric-List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
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eferrer" target="_blank">http://forums.matronics.com
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user9253
Joined: 28 Mar 2008
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Location: Riley TWP Michigan
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kenryan
Joined: 20 Oct 2009
Posts: 424
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| Posted: Fri Jan 22, 2016 12:02 pm Post subject: Rotax 914 Generator, Alternator, Starting and Fuel Pump Con |
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One other thing I was wondering ... does it make any difference if the panel breaker on the integrated generator comes before or after the capacitor?
On Fri, Jan 22, 2016 at 7:40 AM, Ken Ryan <keninalaska(at)gmail.com (keninalaska(at)gmail.com)> wrote:
| Quote: | Thanks Joe. I will move the field wire for the 40 amp alternator away from the bus, maybe to the battery relay. That will eliminate the fuse, leaving only the 5 amp panel breaker on the over voltage/field circuit. I will downsize the 20 amp panel breaker for the 20 amp integrated generator to 10 amps for the reasons you stated.
On Fri, Jan 22, 2016 at 6:01 AM, user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:
| Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>
1. Over voltage protection.
Bob Nuckolls made a demonstration board for an court trial. He made a movie showing what happens when fuses or circuit breakers are in series. If Bob is reading, maybe he can provide a link to that movie. It was interesting. Anyway, even a 10 amp fuse might blow before a 5 amp series breaker trips. The fuse needs to be slow blow and much larger than the circuit breaker. Or do not put protection devices in series.
2. Understand
3. The capabilities of an EFIS are amazing.
4. OK
5. The reason that I suggested using a smaller breaker for the output of the 20 amp dynamo is that in the event of a short circuit, a 20 amp breaker might not ever trip because the dynamo will struggle to put out that much current. The AC coils or regulator could overheat. Since the fuel pump is the only load and requires less than 10 amps, a larger breaker is not needed.
Have fun with your project.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=452191#452191
===========
br> fts!)
r> > w.buildersbooks.com" rel="noreferrer" target="_blank">www.buildersbooks.com
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
-Matt Dralle, List Admin.
===========
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Electric-List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
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FORUMS -
eferrer" target="_blank">http://forums.matronics.com
===========
b Site -
-Matt Dralle, List Admin.
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
===========
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user9253
Joined: 28 Mar 2008
Posts: 1908
Location: Riley TWP Michigan
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| Posted: Fri Jan 22, 2016 2:17 pm Post subject: Re: Rotax 914 Generator, Alternator, Starting and Fuel Pump |
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| Quote: | | does it make any difference if the panel breaker on the integrated generator comes before or after the capacitor? |
It will work in either location.
But I think it is best the way you have it pictured.
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rickofudall
Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA
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| Posted: Sat Jan 23, 2016 9:32 am Post subject: Rotax 914 Generator, Alternator, Starting and Fuel Pump Con |
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In the Rotax two stroke engine rectifier/regulator they had two options;
one required a battery, the other didn't. The one that didn't require a
battery had a built in load, a cap, to get the dynamo to produce current.
Anecdotally, many years ago a friend of my son's was building up a Harley
Sportster rat bike. It was the old engine with a generator and magneto. He
brought it to me to put together the electrical system and said he didn't
want to run a battery if he didn't absolutely have to. I found a kit to do
just that, and it was, wait for it..... A big capacitor with a spring mount
so that vibration of the off balance VTwin wouldn't beat it to death. As I
recall the kit was all of $16 back then. I wired it up per instructions and
it worked like a charm.
Rick GIrard
On Fri, Jan 22, 2016 at 8:00 PM, GTH <gilles.thesee(at)free.fr> wrote:
[quote]
*Le 23/01/2016 02:24, Robert L. Nuckolls, III a écrit : *
* The legacy capacitor included in virtually every PM alternator
architecture will be examined in detail with a goal of putting numbers
on its efficacy.*
Hi Bob and all,
About 13 years ago during the build of our project, I had the opportunity
to conduct some experiments with the Rotax 914 alternator & voltage
regulator.
We discovered that the Rotax voltage regulator doesn't start delivering
energy unless it is subject to some voltage from the battery or capacitor
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