Today's Message Index:
----------------------
1. 05:19 AM - Re: BASIC DUAL INDEPENDENT POWER SUPPLY (Ken)
2. 09:32 AM - Re: Magnetometer Location in RV-7 (Larry L. Tompkins, P.E.)
3. 05:16 PM - Re: BASIC DUAL INDEPENDENT POWER SUPPLY (Robert L. Nuckolls, III)
4. 05:54 PM - Re: BASIC DUAL INDEPENDENT POWER SUPPLY (Peter Harris)
Message 1
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| Subject: | Re: BASIC DUAL INDEPENDENT POWER SUPPLY |
Peter
Much as I hate attachments (slow dial up connection), I took a quick
look and I really think you are kidding yourself about this.
Look at all the things that can fail your alternator and it's wiring. I
suspect that a modern sealed battery is an order of magnitude more
reliable for its first couple of years of life. Even in the unlikely
event that the battery did fail, it is unlikely to do so in a manner
that will bring down your system. I suspect that your proposal adds no
reliability to your electrical supply. A separate small battery would be
there if it were my system and I was concerned about supply reliability.
Yes I'd keep a fuselink, C/B, or fuse near the battery so that a short
in the alternator or all that wiring doesn't draw a lot of current out
of the battery.
Now for the sake of discussion... If you really want to do this - what
about considering a separate alternator feed right from the alternator
that would include a second rectifier/regulator operating with or
without a separate battery ;) Separate wiring and no excess connections
such as loadmeters.
The last time I bought a battery, there was a well dressed guy trying to
talk the price down a bit on a flooded cell motorcycle battery. When I
asked for a small AGM battery by part number, the salesman said "so nice
to have a customer that understands value". Both batteries were
interchangeble but mine was over twice the money and should last many
times longer than the cheap one.
Ken
Peter Harris wrote:
> Bob,
>
> I have been guilty of asking a lot of questions before reading your
> files and thanks to Gilles, Ken and yourself for the advice and patience.
>
> Your files are a gold mine of good engineering design.
>
> My project is for conversion of a Quickie Q-200 with Jab 3300 single
> phase PM alternator and a regulator like the SD-8 setup to make a safe
> dual independent power supply ready for an EFI conversion.
>
> The original Quickie circuit has no relays and protection is by fuses
> to each connection and the DPST master switch which isolates battery
> from alternator from bus.
>
> Z-25 covers everything I think I need except for the dual independent
> source for the ebus.
>
> For this I have copied a practice I have seen here in Oz which I
> understand is approved by CASA as a dual independent power supply by
> taking the centre tap from two diodes back to back and I have shown
> the setup at the bottom of Z-25 following. I have also included an
> over current module A which I had from another installation. (Gilles
> has pointed out that either the fusible link or the OCM is redundant).
>
> The ebus feed that I have shown here is I think similar to what you
> have done in Z-19 note 24.
>
> I want to keep the thing as simple as possible and have left the SPDT
> master switch but would use a relay if you advise.
>
> I would welcome your advice on the merits of fusible links vs CB which
> reset or can be reset, and whether you think the OCM is worth keeping,
> or if you see something wrong with the diagram.
>
> Thanks
>
> Peter.
>
Message 2
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| Subject: | Re: Magnetometer Location in RV-7 |
Bob,
Thank you for continuing to educate me once again . Based on your
comments as well as David Abrahamson's installation and positive
experience with that location, I am satisfied that David's fuselage
location is an excellent one.
In case you haven't been following this thread, David fabricated a
horizontal shelf high in his RV-7's empennage and just behind the
baggage compartment rear bulkhead. His GRT magnetometer is attached to
that shelf. While that location does not quite meet the GRT
recommendation of 18" away from the baggage compartment, he has positive
test data to support the use of that location. Anything heavy or
ferrous is probably going to be close to the baggage compartment floor,
which IS more than 18" from that location.
David also e-mailed me photos of the installation that are very helpful.
He has a nice website documenting his RV-7's construction as well.
Larry Tompkins
Message 3
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| Subject: | Re: BASIC DUAL INDEPENDENT POWER SUPPLY |
At 04:24 PM 5/3/2007 +1000, you wrote:
>Bob,
>
>
>I have been guilty of asking a lot of questions before reading your files
>and thanks to Gilles, Ken and yourself for the advice and patience.
No problem. Let's see if we can speed up the process
of getting the nuts separated from the shells.
>Your files are a gold mine of good engineering design.
I thank you for the kind words . . .
>My project is for conversion of a Quickie Q-200 with Jab 3300 single phase
>PM alternator and a regulator like the SD-8 setup to make a safe dual
>independent power supply ready for an EFI conversion.
>
>The original Quickie circuit has no relays and protection is by fuses to
>each connection and the DPST master switch which isolates battery from
>alternator from bus.
>
>Z-25 covers everything I think I need except for the dual independent
>source for the ebus.
>
>For this I have copied a practice I have seen here in Oz which I
>understand is approved by CASA as a dual independent power supply by
>taking the centre tap from two diodes back to back and I have shown the
>setup at the bottom of Z-25 following. I have also included an over
>current module A which I had from another installation. (Gilles has
>pointed out that either the fusible link or the OCM is redundant).
Hmmm . . . when folks "who know more about building airplanes than we do"
get into the loop . . . well. Let's not go there.
>The ebus feed that I have shown here is I think similar to what you have
>done in Z-19 note 24.
>
>I want to keep the thing as simple as possible and have left the SPDT
>master switch but would use a relay if you advise.
>
>I would welcome your advice on the merits of fusible links vs CB which
>reset or can be reset, and whether you think the OCM is worth keeping, or
>if you see something wrong with the diagram.
How do you plan to use this airplane. Are you intending to
file for flight into IMC? Are you planning a vacuum system or
all electric? What plans do you have for electronic and/or attitude
displays?
Do you plan a wing leveler? GPS or magnetically aided . . . or both?
Do you plan to fly at night? What equipment items did you plan to
power from the e-bus?
Bob . . .
----------------------------------------
( IF one aspires to be "world class", )
( what ever you do must be exercised )
( EVERY day . . . )
( R. L. Nuckolls III )
----------------------------------------
Message 4
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| Subject: | BASIC DUAL INDEPENDENT POWER SUPPLY |
Bob,
The aircraft will be used only for VFR day. It is equipped with a compass
and a GPS for nav and the usual engine instruments all of which are fused
off the main bus. For ignition it has a single electronic ignition module
and a single magneto. I also have a Ray Allen T2-7A servo for aileron reflex
which is non essential.
No wing leveler or other electricals. No pneumatics .
For monitoring the electrical system I have a dual voltmeter/ampmeter also
an alternator no charge warning light. I have ordered the OVM crowbar module
and have the parts to do the self excitation as in Z-25. The jab regulator
looks like it is in the same family as the PMR 1-14.
>From the ebus I plan to supply an EFI system including an ECU, Fuel pump and
two injectors as well as the EI module. Total load is expected to be less
than 8A. I would use LED s to indicate each of the dual sources active and
would operate with both sources normally active.
Thanks Bob
Peter
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L.
Nuckolls, III
Sent: Friday, 4 May 2007 11:15 AM
Subject: Re: AeroElectric-List: BASIC DUAL INDEPENDENT POWER SUPPLY
<nuckollsr@cox.net>
At 04:24 PM 5/3/2007 +1000, you wrote:
>Bob,
>
>
>I have been guilty of asking a lot of questions before reading your files
>and thanks to Gilles, Ken and yourself for the advice and patience.
No problem. Let's see if we can speed up the process
of getting the nuts separated from the shells.
>Your files are a gold mine of good engineering design.
I thank you for the kind words . . .
>My project is for conversion of a Quickie Q-200 with Jab 3300 single phase
>PM alternator and a regulator like the SD-8 setup to make a safe dual
>independent power supply ready for an EFI conversion.
>
>The original Quickie circuit has no relays and protection is by fuses to
>each connection and the DPST master switch which isolates battery from
>alternator from bus.
>
>Z-25 covers everything I think I need except for the dual independent
>source for the ebus.
>
>For this I have copied a practice I have seen here in Oz which I
>understand is approved by CASA as a dual independent power supply by
>taking the centre tap from two diodes back to back and I have shown the
>setup at the bottom of Z-25 following. I have also included an over
>current module A which I had from another installation. (Gilles has
>pointed out that either the fusible link or the OCM is redundant).
Hmmm . . . when folks "who know more about building airplanes than we
do"
get into the loop . . . well. Let's not go there.
>The ebus feed that I have shown here is I think similar to what you have
>done in Z-19 note 24.
>
>I want to keep the thing as simple as possible and have left the SPDT
>master switch but would use a relay if you advise.
>
>I would welcome your advice on the merits of fusible links vs CB which
>reset or can be reset, and whether you think the OCM is worth keeping, or
>if you see something wrong with the diagram.
How do you plan to use this airplane. Are you intending to
file for flight into IMC? Are you planning a vacuum system or
all electric? What plans do you have for electronic and/or attitude
displays?
Do you plan a wing leveler? GPS or magnetically aided . . . or both?
Do you plan to fly at night? What equipment items did you plan to
power from the e-bus?
Bob . . .
----------------------------------------
( IF one aspires to be "world class", )
( what ever you do must be exercised )
( EVERY day . . . )
( R. L. Nuckolls III )
----------------------------------------
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