Today's Message Index:
----------------------
1. 05:16 AM - Re: Future replacement for Rotax (klehman@albedo.net)
2. 07:01 AM - Re: Future replacement for Rotax (Robert L. Nuckolls, III)
3. 07:06 AM - How to Mount Ground Power Connector (Condrey, Bob (US SSA))
4. 07:21 AM - Re: Future replacement for Rotax (David Carter)
5. 08:19 AM - Re: Future replacement for Rotax (Randy)
6. 09:19 AM - Dual voltage electrical system (Richard@riley.net)
7. 09:58 AM - GPS antenna (Joel Harding)
8. 11:06 AM - Re: How to Mount Ground Power Connector (Richard Dudley)
9. 11:24 AM - Re: Dual voltage electrical system (Altoq)
10. 11:27 AM - Re: Dual voltage electrical system (Robert L. Nuckolls, III)
11. 11:32 AM - Re: How to Mount Ground Power Connector (Robert L. Nuckolls, III)
12. 11:36 AM - Re: Rgulator and heat (Robert L. Nuckolls, III)
13. 11:47 AM - Re: Future replacement for Rotax (Robert L. Nuckolls, III)
14. 12:43 PM - Re: Future replacement for Rotax (Matt Prather)
15. 01:56 PM - Re: Future replacement for Rotax (Randy)
16. 02:49 PM - Re: Dual voltage electrical system (richard@riley.net)
17. 07:11 PM - Re: Dual voltage electrical system (Robert L. Nuckolls, III)
18. 07:37 PM - Starter Help (BAKEROCB@aol.com)
19. 09:32 PM - Fuse Blown Indicators (andrew manzo)
20. 10:20 PM - Re: Fuse Blown Indicators (Chad Robinson)
Message 1
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| Subject: | Re: Future replacement for Rotax |
--> AeroElectric-List message posted by: klehman@albedo.net
Yes it's the AM877557 20 amp John Deere alternator and the AM101406
regulator that I was referring to. The regulator itself weighs 190 gm
(about 0.4 lb). It even has fast-on connectors ;)
As mentioned here, I too concluded that it is inefficient and it will
heat up the regulator more by not using the generators output. Therefore
the plan is to use it to power things that I want to run all the time
like exterior lighting. I may run my primary fuel and ignition off it as
well instead of from my small conventional alternator.
Ken
Message 2
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| Subject: | Re: Future replacement for Rotax |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 10:08 PM 11/18/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: "David Carter"
><dcarter@datarecall.net>
>
>Bob, a question raised by your "various loads" phrase in the quoted e-mail
>below:
>
>I've heard that the PM alternator puts out max current for whatever rpm it
>is turning, regardless of load, and that the regulator simply heat sinks all
>the current not being used usefully.
Not necessarily so. Early versions of PM rectifier-regulators were
of the shunt variety. Energy not needed to maintain bus voltage
was dumped into the regulator's heat sink. Hence, an alternator
with NO system loads caused the regulator to run very hot.
The Ducati and B&C rectifier-regulators use a rectifier bridge
of which two devices are silicon controlled rectifiers TRIGGERED
to PASS energy as opposed to SINK energy. These heat up in
response to system loads and run very cool when the system
is lightly loaded.
Bob . .
Message 3
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| Subject: | How to Mount Ground Power Connector |
--> AeroElectric-List message posted by: "Condrey, Bob (US SSA)" <bob.condrey@baesystems.com>
I followed Bob's excellent tutorial on modifying a Piper style ground
power connector. My question now is, how are these usually mounted? It
is certainly a big, clunky connector and my assumption is that it is
somehow hidden behind a hinged cover. How have others mounted this?
Does anybody have a picture/drawing of how it's done on Piper aircraft?
I know, I could drive out to the airport and look but my assumption is
that those that have gone before me have most likely improved on the
Piper's approach.
Thanks
Bob
Message 4
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| Subject: | Re: Future replacement for Rotax |
--> AeroElectric-List message posted by: "David Carter" <dcarter@datarecall.net>
Then perhaps I can call or e-mail John Deere today and get someone to call
back and inform me which type they use - shunt or SCR triggered.
David
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
Subject: Re: AeroElectric-List: Future replacement for Rotax
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
>
> At 10:08 PM 11/18/2003 -0600, you wrote:
> >--> AeroElectric-List message posted by: "David Carter"
> ><dcarter@datarecall.net>
> >
> >Bob, a question raised by your "various loads" phrase in the quoted
e-mail
> >below:
> >
> >I've heard that the PM alternator puts out max current for whatever rpm
it
> >is turning, regardless of load, and that the regulator simply heat sinks
all
> >the current not being used usefully.
>
> Not necessarily so. Early versions of PM rectifier-regulators were
> of the shunt variety. Energy not needed to maintain bus voltage
> was dumped into the regulator's heat sink. Hence, an alternator
> with NO system loads caused the regulator to run very hot.
>
> The Ducati and B&C rectifier-regulators use a rectifier bridge
> of which two devices are silicon controlled rectifiers TRIGGERED
> to PASS energy as opposed to SINK energy. These heat up in
> response to system loads and run very cool when the system
> is lightly loaded.
>
> Bob . .
>
>
Message 5
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| Subject: | Re: Future replacement for Rotax |
--> AeroElectric-List message posted by: "Randy" <rnvcrothers@comcast.net>
Hi all,
I have not been on this list for quite a while but now I am close to
actually wiring so I am monitoring again.
Just a note about my experience with PM alternators. I work on
equipment that runs 24/7. Until I switched to running PM alternators, by
far the most common failure was alternator brushes. I could not predict how
long they would last. Sometimes they would only make it three months,
others maybe six or seven months. Once I switched to the PM alternators I
have not had one fail, and they have racked up a significant amount of hours
on them. In one case at least a full year running at 24/7 with no
problems. The bearings seem to be quite good also. The only problem is
they are large and at least twice as heavy as the normal alternators they
replaced. I am wondering if a suitable, smaller PM alternator with
sufficient output might be available for aircraft use.
After seeing so many alternator failures I am not overly confident in
relying on one in my RV7A with Subaru power, which certainly needs some
electricity to keep running. My engine came with an ND mini alternator with
55 amps output. I will of course have a backup battery but a more robust
alternator would be nice if one were available.
Due to my experiences above, I have left my old generator in my 1959
C182, even though I have all the stuff needed to convert it to use of an
alternator. I may be wrong, but it seems like a generator with good brushes
etc. is a pretty reliable unit.
OK here is the question I have been trying to get to. When I had my
little ND mini alternator load tested at a local alternator starter rebuild
shop, the owner recommended designing a system that uses no more than 50% of
it's rated output for continuous load. Now that I am adding up what might
be my maximum continuous load, I am finding that 50% of 55 amps is pretty
restrictive. Have any of you heard of this recommendation before? Does
loading an alternator beyond the 50% mark for continuous load begin to have
an effect on reliability? I understand the heat issue and it will certainly
make more heat at higher loads so cooling air directed to it is a good
thing.
Sorry this got so long...
Randy
----- Original Message -----
From: <klehman@albedo.net>
Subject: Re: AeroElectric-List: Future replacement for Rotax
> --> AeroElectric-List message posted by: klehman@albedo.net
>
> Yes it's the AM877557 20 amp John Deere alternator and the AM101406
> regulator that I was referring to. The regulator itself weighs 190 gm
> (about 0.4 lb). It even has fast-on connectors ;)
>
> As mentioned here, I too concluded that it is inefficient and it will
> heat up the regulator more by not using the generators output. Therefore
> the plan is to use it to power things that I want to run all the time
> like exterior lighting. I may run my primary fuel and ignition off it as
> well instead of from my small conventional alternator.
>
> Ken
>
>
Message 6
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| Subject: | Dual voltage electrical system |
--> AeroElectric-List message posted by: Richard@Riley.net
This one is going to be a mess, but I'll throw it open for comments.
I'm going to have to run a 28 v 60 amp alternator in my airplane. The
reasons are complex, but I have to.
My airplane is currently built with a 12v electrical system. Many of the
most expensive bits don't care if they're getting 12 or 24 volts - the
radio stack, the Blue Mountain EFIS, the strobes, the electronic ignition -
are happy either way.
Some of the other bits do care, but are cheap - position lights, for example.
But there are some that are both very expensive, and rated for 14 v, that I
really don't want to - or can't - change.
Hydraulic (main gear) pump
Nose gear motor (I can't change that, it doesn't exist in 24v)
Pitch and roll trim motors
Landing brake motor
Fuel pump (35 PSI, fuel injected engine)
Observations:
1) They're all motors
2) Except for the fuel pump, they're by their nature used briefly and
sporadically.
3) The gear motors take a lot of current. The hydraulic pump is listed at
35 amps, the nose gear at 15.
So far, I've thought of
Running a 14v SD-8 and a 5 AH battery just to power those things.
Running a 28v SD20 or SD-8 and a DC/DC converter, charging a 5 AH battery
for a 14 v bus.
Putting a resistor in line with each of the 12v devices
Ignoring them except the fuel pump, figuring that in the few seconds
they're running the over voltage won't be able to overheat them. Put a
resistor on the fuel pump.
Any other thoughts, flames, musings, amusing anecdotes?
Message 7
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--> AeroElectric-List message posted by: Joel Harding <cajole76@ispwest.com>
I have seen pictures of the GPS antenna mount on the front of the
firewall, but can't recall which web site they were on. Can someone
with a better memory help me out here? Since I've seen no reports of
difficulties with that location, I think I'll try it.
Joel Harding (waiting on the GRR EFIS to finish up the panel)
Message 8
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| Subject: | Re: How to Mount Ground Power Connector |
--> AeroElectric-List message posted by: Richard Dudley <rhdudley@att.net>
Bob,
I've attached a photo (which will be filtered out for the list) of the
outside of the receptacle. Unfortunately, I
did not photograph the inside. I pretty much followed Bob's directions
including the toilet seat bolt for the center conductor. I made a
doubler of .063 that I riveted to the skin to reinforce the area. I used
Bob's design with the switch breaker, light and reverse polarity
protection. The circuit works well and is very convenient when testing
the electrical system and avionics while keeping the battery charged. I
connect a battery charger to the external plug and run the charger when
I am testing or running the system.
Hope this helps.
Regards,
Richard Dudley
-6A myriad of finishing details
Condrey, Bob (US SSA) wrote:
>
> --> AeroElectric-List message posted by: "Condrey, Bob (US SSA)" <bob.condrey@baesystems.com>
>
> I followed Bob's excellent tutorial on modifying a Piper style ground
> power connector. My question now is, how are these usually mounted? It
> is certainly a big, clunky connector and my assumption is that it is
> somehow hidden behind a hinged cover. How have others mounted this?
> Does anybody have a picture/drawing of how it's done on Piper aircraft?
> I know, I could drive out to the airport and look but my assumption is
> that those that have gone before me have most likely improved on the
> Piper's approach.
>
> Thanks
> Bob
>
Message 9
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| Subject: | Re: Dual voltage electrical system |
--> AeroElectric-List message posted by: Altoq <altoq@direcway.com>
Food for Thought: If you just use two 12v batteries, in series for 24v, the
connector between them is 12v. You got it, take it from there.
John D.
----- Original Message -----
From: <Richard@riley.net>
Subject: AeroElectric-List: Dual voltage electrical system
> --> AeroElectric-List message posted by: Richard@Riley.net
>
> This one is going to be a mess, but I'll throw it open for comments.
>
> I'm going to have to run a 28 v 60 amp alternator in my airplane. The
> reasons are complex, but I have to.
>
> My airplane is currently built with a 12v electrical system. Many of the
> most expensive bits don't care if they're getting 12 or 24 volts - the
> radio stack, the Blue Mountain EFIS, the strobes, the electronic
ignition -
> are happy either way.
>
> Some of the other bits do care, but are cheap - position lights, for
example.
>
> But there are some that are both very expensive, and rated for 14 v, that
I
> really don't want to - or can't - change.
>
> Hydraulic (main gear) pump
> Nose gear motor (I can't change that, it doesn't exist in 24v)
> Pitch and roll trim motors
> Landing brake motor
> Fuel pump (35 PSI, fuel injected engine)
>
> Observations:
> 1) They're all motors
> 2) Except for the fuel pump, they're by their nature used briefly and
> sporadically.
> 3) The gear motors take a lot of current. The hydraulic pump is listed at
> 35 amps, the nose gear at 15.
>
> So far, I've thought of
>
> Running a 14v SD-8 and a 5 AH battery just to power those things.
>
> Running a 28v SD20 or SD-8 and a DC/DC converter, charging a 5 AH battery
> for a 14 v bus.
>
> Putting a resistor in line with each of the 12v devices
>
> Ignoring them except the fuel pump, figuring that in the few seconds
> they're running the over voltage won't be able to overheat them. Put a
> resistor on the fuel pump.
>
> Any other thoughts, flames, musings, amusing anecdotes?
>
>
Message 10
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| Subject: | Re: Dual voltage electrical system |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:18 AM 11/19/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: Richard@Riley.net
>
>This one is going to be a mess, but I'll throw it open for comments.
>
>I'm going to have to run a 28 v 60 amp alternator in my airplane. The
>reasons are complex, but I have to.
>
>My airplane is currently built with a 12v electrical system. Many of the
>most expensive bits don't care if they're getting 12 or 24 volts - the
>radio stack, the Blue Mountain EFIS, the strobes, the electronic ignition -
>are happy either way.
>
>Some of the other bits do care, but are cheap - position lights, for example.
>
>But there are some that are both very expensive, and rated for 14 v, that I
>really don't want to - or can't - change.
>
>Hydraulic (main gear) pump
>Nose gear motor (I can't change that, it doesn't exist in 24v)
>Pitch and roll trim motors
>Landing brake motor
>Fuel pump (35 PSI, fuel injected engine)
Do you have dual fuel pumps. E.g.: is this the
only fuel pump or is there a mechanical one too?
How much current does the fuel pump draw?
Bob . . .
Message 11
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| Subject: | Re: How to Mount Ground Power Connector |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 07:05 AM 11/19/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: "Condrey, Bob (US SSA)"
><bob.condrey@baesystems.com>
>
>I followed Bob's excellent tutorial on modifying a Piper style ground
>power connector. My question now is, how are these usually mounted? It
>is certainly a big, clunky connector and my assumption is that it is
>somehow hidden behind a hinged cover. How have others mounted this?
>Does anybody have a picture/drawing of how it's done on Piper aircraft?
>I know, I could drive out to the airport and look but my assumption is
>that those that have gone before me have most likely improved on the
>Piper's approach.
On the airplanes I've seen, they're mounted low on the
fuselage, behind the wing and as close as practical to
the battery contactor which is under the rear seat.
Many builders have installed them on brackets in the
cockpit but out of the way so that then don't put
a hole in the fuselage. I think behind the wing
is a good spot . . . convenient to line support
persons while away from the prop.
Bob . . .
Message 12
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| Subject: | Re: Rgulator and heat |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:30 AM 11/19/2003 +0100, you wrote:
>--> AeroElectric-List message posted by: "Werner Schneider"
><wernerschneider@compuserve.com>
>
> >
> > I usually try to deduce some sense of thermal impedance
> > between internal semi-conductors and the case.
>
> > any head-room in the design. There is NO headroom for cooling
> > in the Ducati regulator used on the Rotax. Mounting this regulator
> > with a blast-tube of cooling air is a good thing to do.
>
>Hello Bob,
>
>this brings me to a point, I have mounted my LR-3 on the left hand side of
>the foot room, about 1.5 ft from the floor, but my heating is blowing partly
>on to the regulator (and believe me we need this heating here in
>Switzerland), reading your posting would you think it would be a wise idea
>to add a heat deflector to protect the regulator? Standard load VFR day is
>around 12-17 A.
The LR-3 is a totally different breed of cat. It controls a wound-field
alternator and never sees more that 3A of current and dissipates a maximum
of 10 watts. Unless you have a REALLY good heater (lots of HOT air) it's
likely that your LR-3 will run cooler being swept by warm air in motion
than it will by setting in a cooler, still air environment. Adding
motion to cooling air has such a profound effect on heat energy transferred
that moving warm air is often better cooling that motionless cold air.
Bob . . .
Message 13
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| Subject: | Re: Future replacement for Rotax |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:20 AM 11/19/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: "Randy" <rnvcrothers@comcast.net>
>
>Hi all,
> I have not been on this list for quite a while but now I am close to
>actually wiring so I am monitoring again.
> Just a note about my experience with PM alternators. I work on
>equipment that runs 24/7. Until I switched to running PM alternators, by
>far the most common failure was alternator brushes. I could not predict how
>long they would last. Sometimes they would only make it three months,
>others maybe six or seven months. Once I switched to the PM alternators I
>have not had one fail, and they have racked up a significant amount of hours
>on them. In one case at least a full year running at 24/7 with no
>problems. The bearings seem to be quite good also. The only problem is
>they are large and at least twice as heavy as the normal alternators they
>replaced. I am wondering if a suitable, smaller PM alternator with
>sufficient output might be available for aircraft use.
> After seeing so many alternator failures I am not overly confident in
>relying on one in my RV7A with Subaru power, which certainly needs some
>electricity to keep running. My engine came with an ND mini alternator with
>55 amps output. I will of course have a backup battery but a more robust
>alternator would be nice if one were available.
This is apples and oranges. A 24/7 environment puts as many hours
on an alternator in two days than the average airplane gets
in a year. Two weeks of operation will put more hours on the
24/7 machine than you are likely to put on your airplane the
total time you own it.
> Due to my experiences above, I have left my old generator in my 1959
>C182, even though I have all the stuff needed to convert it to use of an
>alternator. I may be wrong, but it seems like a generator with good brushes
>etc. is a pretty reliable unit.
> OK here is the question I have been trying to get to. When I had my
>little ND mini alternator load tested at a local alternator starter rebuild
>shop, the owner recommended designing a system that uses no more than 50% of
>it's rated output for continuous load. Now that I am adding up what might
>be my maximum continuous load, I am finding that 50% of 55 amps is pretty
>restrictive. Have any of you heard of this recommendation before? Does
>loading an alternator beyond the 50% mark for continuous load begin to have
>an effect on reliability? I understand the heat issue and it will certainly
>make more heat at higher loads so cooling air directed to it is a good
>thing.
This is BS. Start with a load analysis on what you know you're
really going to need and under what conditions. I've done many a
load analysis and to date, the largest, continuous load I've
seen for a 14v airplane was 27A. So even a 40A machine is taxed
to 67% of capacity and rarely. Alternator life is not related
to loading as long as the alternator gets adequate cooling. You
can burn up a 40A alternator with a 20A load if you choke the cooling
off.
You got the cart in front of the horse. The ND alternator has
a long and successful service record in thousands of airplanes.
Line your ducks up for more important details of your design.
That alternator is going to be just fine.
Have you read chapter 17 of the 'Connection? If not, you can
download at:
http://www.aeroelectric.com/articles/Rev9/ch17-9.pdf
Bob . . .
Message 14
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| Subject: | Re: Future replacement for Rotax |
--> AeroElectric-List message posted by: "Matt Prather" <mprather@spro.net>
Randy,
Alternator brush life is related to the quality of the surface
that they ride on. Was part of your brush replacement practice
to inspect and polish the surface where the brush makes electrical
contact?
Regards,
Matt Prather
N34RD
> --> AeroElectric-List message posted by: "Randy"
> <rnvcrothers@comcast.net>
>
> Hi all,
> I have not been on this list for quite a while but now I am close to
> actually wiring so I am monitoring again.
> Just a note about my experience with PM alternators. I work on
> equipment that runs 24/7. Until I switched to running PM alternators,
> by far the most common failure was alternator brushes. I could not
> predict how long they would last. Sometimes they would only make it
> three months, others maybe six or seven months. Once I switched to the
> PM alternators I have not had one fail, and they have racked up a
snip
Message 15
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| Subject: | Re: Future replacement for Rotax |
--> AeroElectric-List message posted by: "Randy" <rnvcrothers@comcast.net>
Matt,
I did not replace the brushes, I always took them to the overhauler and
exchanged them. I hear what you are saying about the surface though.
Thanx. Randy
----- Original Message -----
From: "Matt Prather" <mprather@spro.net>
Subject: Re: AeroElectric-List: Future replacement for Rotax
> --> AeroElectric-List message posted by: "Matt Prather"
<mprather@spro.net>
>
> Randy,
>
> Alternator brush life is related to the quality of the surface
> that they ride on. Was part of your brush replacement practice
> to inspect and polish the surface where the brush makes electrical
> contact?
>
> Regards,
>
> Matt Prather
> N34RD
>
> > --> AeroElectric-List message posted by: "Randy"
> > <rnvcrothers@comcast.net>
> >
> > Hi all,
> > I have not been on this list for quite a while but now I am close to
> > actually wiring so I am monitoring again.
> > Just a note about my experience with PM alternators. I work on
> > equipment that runs 24/7. Until I switched to running PM alternators,
> > by far the most common failure was alternator brushes. I could not
> > predict how long they would last. Sometimes they would only make it
> > three months, others maybe six or seven months. Once I switched to the
> > PM alternators I have not had one fail, and they have racked up a
>
> snip
>
>
Message 16
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| Subject: | Re: Dual voltage electrical system |
--> AeroElectric-List message posted by: richard@riley.net
--> AeroElectric-List message posted by: "Robert L.
Nuckolls, III" <bob.
nuckolls@cox.net>
>>Hydraulic (main gear) pump
>>Nose gear motor (I can't change that, it doesn't
exist in 24v)
>>Pitch and roll trim motors
>>Landing brake motor
>>Fuel pump (35 PSI, fuel injected engine)
>
>Do you have dual fuel pumps. E.g.: is this the
>only fuel pump or is there a mechanical one too?
>How much current does the fuel pump draw?
Yes, there is a mechanical fuel pump (Lycoming
standard). The electric pump is only used for
starting, takeoff, landing and emergencies. It's
listed as 5 amps in the catalog.
Unfortunately the catalog doesn't list the high
pressure Weldon pump in 24v. It lists the 12 v high
pressure and low pressure (4.5 PSI) but only the 4.5
PSI in the high pressure. I'm sure it can be had by
$pecial order.
Message 17
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| Subject: | Re: Dual voltage electrical system |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 02:49 PM 11/19/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: richard@riley.net
>
>--> AeroElectric-List message posted by: "Robert L.
>Nuckolls, III" <bob.
>nuckolls@cox.net>
>
> >>Hydraulic (main gear) pump
> >>Nose gear motor (I can't change that, it doesn't
>exist in 24v)
> >>Pitch and roll trim motors
> >>Landing brake motor
> >>Fuel pump (35 PSI, fuel injected engine)
> >
> >Do you have dual fuel pumps. E.g.: is this the
> >only fuel pump or is there a mechanical one too?
> >How much current does the fuel pump draw?
>
>Yes, there is a mechanical fuel pump (Lycoming
>standard). The electric pump is only used for
>starting, takeoff, landing and emergencies. It's
>listed as 5 amps in the catalog.
>
>Unfortunately the catalog doesn't list the high
>pressure Weldon pump in 24v. It lists the 12 v high
>pressure and low pressure (4.5 PSI) but only the 4.5
>PSI in the high pressure. I'm sure it can be had by
>$pecial order.
Okay, then ALL of your 14v requirements are intermittent
except the rare case where electric fuel pump backs up
the mechanical one in which case you have a 5A continuous
requirement for remainder of flight.
I think I'd go with a DC-DC converter to step down
28v to 14v -AND- maintain a 14V battery. You need
a battery that's robust enough to handle dynamic loads
of hydraulic pump. l7 a.h. would be easy and cheap,
there are some smaller ones that would take the beating
in the 10 a.h. class but only saves you 5# or so.
You'll need a pair of 17 a.h. batteries on the 28V
side so yearly changeout produces a candidate for
14v service for the second year.
The DC to DC converter would only need to be good
for 10A or so and is relatively small. About 2#
I should think. Your 14V "system" should have a
low-volts warning system but that should be all
that's necessary in the way of instrumentation.
Bob . . .
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
Message 18
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--> AeroElectric-List message posted by: BAKEROCB@aol.com
11/19/2003
Hello Electrical Types, I am seeking help in getting better engine starting
and I'd like you to prescribe the gadget that will do it. Let me explain:
I have a TCM (Teledyne Continental Motors) IO-240 B9B engine. It has a Unison
Slick 4309 direct drive magneto on the right side with a normal running spark
advance of 26 degrees before piston TDC (Top Dead Center). On the left side
is a Slick 4310 magneto with normal running spark advance of 26 degrees before
TDC and also retard breaker points. The retard breaker points retard the spark
to near TDC for proper starting spark during cranking.
The engine is started with only the left magneto ON and the high voltage,
multiple pulse starting spark is provided through the retard breaker points by
a
solid state Unison SlickStart starting vibrator. The 26 degrees before TDC
spark from the normal running points in both magnetos is grounded out by the
SlickStart vibrator while cranking.
Presently the electrical source for the starting vibrator comes from the same
starter contactor terminal that provides electrical power to the starter
motor. When the starter button is released electrical power to both the starter
motor and the starting vibrator ends instantly. It is important in this engine
to release the starter button as soon as the engine initially fires rather than
try to "help it along" until it is running "better". Starter gears get chewed
up if one keeps the starter engaged for any period of time after the engine
initially fires.
But there is a brief period of time after the engine initially fires and
before it starts running better when the engine could benefit from continued high
voltage multiple pulse retarded spark.
So I want a gadget that I can wire into my starter button / starting
contactor / starting vibrator / main bus circuitry such that it will activate the
starting vibrator at the instant that the starter button is pushed and keep
supplying electricity to the vibrator , but not to the starter motor, for 2 or
3
seconds after the starter button is released.
I have heard terms such as "retard delay" thrown around in connection with
the Bendx "Shower of Sparks" starting vibrator (an older mechanical competitor
of the Unison SlickStart vibrator) so I think that the concept is valid and
that such things exist, but they are deeply buried within the Bendix realm and
not available to me.
My request is that you point me at such a delay device so that I can purchase
it.
Many thanks.
'OC' Baker, Builder of KIS TR-1 #116 4/14/97 - 11/17/03
Message 19
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| Subject: | Fuse Blown Indicators |
--> AeroElectric-List message posted by: andrew manzo <andrewmanzo@yahoo.com>
Why not turn the logic on it's head?
Instead of indicating a blown fuse, indicate a good
fuse?
Have a row of LED's - one for each fuse.
When the fuse is good, you get a nice green light from
the LED.
When it is bad, you don't get a light.
If you put a white light on either end, you could see
at a glance that there were no gaps in the green
lights, therefore all is good.
If there is a gap in the green lights, you know which
fuse has popped.
Am I missing something with my solution?
Thanks!
--Andrew
__________________________________
Message 20
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| Subject: | Re: Fuse Blown Indicators |
--> AeroElectric-List message posted by: Chad Robinson <crobinson@rfgonline.com>
On Wed, 19 Nov 2003 21:31:14 -0800 (PST) andrew manzo
<andrewmanzo@yahoo.com> wrote:
> Why not turn the logic on it's head?
>
> Instead of indicating a blown fuse, indicate a good
> fuse?
>
> Have a row of LED's - one for each fuse.
>
> When the fuse is good, you get a nice green light from
> the LED.
>
> When it is bad, you don't get a light.
>
> If you put a white light on either end, you could see
> at a glance that there were no gaps in the green
> lights, therefore all is good.
>
> If there is a gap in the green lights, you know which
> fuse has popped.
>
> Am I missing something with my solution?
Nope, that would work fine. It's pretty easy to wire, too - the LEDs just hook
up to the downstream side of the fuse box. It's a nice way to go if you're the
sort that's doing, say, a lot of engine experimentation, because it could help
remind you that you left, say, one of the electric water pump fuses out on your
last maintenance cycle - no wonder those engine temps are high.
Of course, it does tend to flood the pilot with information if that fuse panel
is visible - you see a lot of lights all the time. It's sort of a personal preference
consideration there.
You could also do this with a microcontroller. Basically, you'd have it look at
the bottom side of any fuse, and it could show a fuse slot number on a 2-digit
LED display if there was a problem. The nice thing about this is that it could
also be your gear-up/gear-dn (UP/DN) display, and cycle back and forth if a
fuse is blown or missing.
My personal favorite is still the push-to-test solution. It doesn't give the pilot
information unless s/he requests it, but when you want it, it's there. And
it wouldn't introduce the stray current into the circuit mentioned by a previous
poster.
Lots of ways to go. None of this is really important to me, I was just wishing
for a commercial solution. I've got enough work to do making my glass cockpit
that I didn't want to have to mince around with fuse blocks and indicators.
Regards,
Chad
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