Today's Message Index:
----------------------
1. 05:23 AM - Fuel sys config, was Fuel Pump Switch(es) (glen matejcek)
2. 05:49 AM - Re: Whelen Strobes Blowing Fuses (Robert L. Nuckolls, III)
3. 07:18 AM - Re: Fuel Pump Switch(es) (Gary Casey)
4. 07:46 AM - Re: Fuel Pump Switch(es) (Hinde, Frank George (Corvallis))
5. 07:47 AM - Re: Whelen Strobes Blowing Fuses (Peter Braswell)
6. 08:50 AM - Re: Whelen Strobes Blowing Fuses (Matt Prather)
7. 09:05 AM - Re: Whelen Strobes Blowing Fuses (Peter Braswell)
8. 09:48 AM - Re: Fuel Pump Switch(es)Fuel Pump Switch(es)Fuel Pump Switch(es) (John Burnaby)
9. 12:40 PM - Re: Whelen Strobes Blowing Fuses (james wickert)
10. 12:59 PM - Re: AeroElectric-List Digest: 26 Msgs - 09/10/06 (Speedy11@aol.com)
11. 06:18 PM - Re: Alternator Problem - Not in plane (Bob White)
12. 06:18 PM - Re: Whelen Strobes Blowing Fuses (Robert L. Nuckolls, III)
13. 06:18 PM - Re: Fuel Pump Switch(es) (Kevin Horton)
14. 06:29 PM - Re: Whelen Strobes Blowing Fuses (Peter Braswell)
15. 07:02 PM - Re: Whelen Strobes Blowing Fuses (Robert L. Nuckolls, III)
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Subject: | Fuel sys config, was Fuel Pump Switch(es) |
--> AeroElectric-List message posted by: "glen matejcek" <aerobubba@earthlink.net>
Hello Brian!
As ever, you are absolutely correct. My bad. I know better than to use
absolutes, especially with this crowd1
On the other hand, the systems you've cited feed from the mains to a header
tank at the low point. This arrangement should preclude drawing air from
the empty tank. In my RV, the fuel pick up in the tank is the low point in
the system. It's all uphill from there, and there is no header tank to
buffer the system. To the best of my knowledge, and I cringe as I type the
words, there are no certified, low wing singles that will feed
simultaneously from multiple tanks other than those equipped with headers.
As a point of interest, does anybody out there know of a plane configured
that way?
>On Mon, 2006-09-11 at 08:57, Bill Denton wrote:
>> RE: Kevin, besides all the good points George makes,
>> and as someone pointed out a while back on one of these lists, you will
>> only find a "BOTH" position on a fuel selector in a high wing single
engine
>> airplane.
>
>Well, it is probably not safe to use the words "always", "never", and
>"only" when describing systems. As I pointed out earlier, both the
>Nanchang CJ6A and Yak-52 are low-wing aircraft that have only an on/off
>fuel selector at the firewall. There is no way on either of these
>aircraft to select a left or right tank. They are always on "both".
>
>Brian Lloyd
glen matejcek
aerobubba@earthlink.net
Message 2
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Subject: | Re: Whelen Strobes Blowing Fuses |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 09:01 PM 9/11/2006 -0400, you wrote:
>Gang,
>I've got a problem with my Whelen strobe system blowing a 10 amp fuse.
>
>I'm using a 10 amp mini-blade fuse which is blowing intermittently. The
>kit manufacturer as per the instructions, recommends a 10 amp fuse, but of
>course they allude to a 10 amp aircraft style reset-able fuse. I can seem
>to get the fuse to blow fairly regularly if I turn the strobes on and off
>in quick succession. The fuse will blow less reliably if I turn the
>strobes on prior to takeoff and just leave them on.
>
>My questions are these: Would there be any difference in a 10 amp blade
>fuse vs. the mechanical breaker style fuse as prescribed by the
>manufacturer? And the other question is is there such thing as a slow-blow m
How old is this system? Is this a "new" phenomenon that's
popped up after a period of satisfactory operation or has
it existed from square-one? Have you placed an ammeter in
series with the supply line to measure the system's current
draw? You need an analog meter to get some notion of minimum
and maximum current between firings. Which strobe system is it?
>ini blade style fuse and could this possibly make a difference? And
>finally perhaps there is something more insidious at work here?
Fuses are faster to respond than most breakers. It could
be that your strobes are drawing an average well below
the 10A rating of the fuse but hit it repeatedly with
levels that exceed 10A and degrade the fuse over a period
of time.
The real definitive measurement would be to put a data acquisition
system on it and watch it for a period of time and the compare
that data with a system that performs as expected. Unfortunately,
most folks in your position don't have access to such equipment
and you're stuck with hip-shots hopefully filtered through some sense
of the physics.
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
Message 3
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Subject: | Re: Fuel Pump Switch(es) |
I might have missed some of the discussion, but the comment below
seems to be directed at the tank valving method - specifically
whether to use two separate fuel valves or one, with the
recommendation to run all the fuel through one valve. I chose to put
two valves on mine for the following reasons:
1. A single valve is a single point of failure - what if the handle
breaks off or the valve sticks? The most likely time for that to
happen is when one port is being closed off before the other opens
(apparently most or all fuel selectors go to "off" between right and
left positions). If it jams in this position all fuel is shut off.
My on-off valves are completely independent and controlled from their
own lever and cable. If one jams either open or shut the other is
unaffected.
2. The fuel can be shut off at the tank, not in the middle of the
cockpit. When both valves are shut off no fuel can enter the
cockpit, which would be reassuring in case of an off-airport landing.
3. It reduces the number of fuel fittings and therefore the number
of potential leak paths, especially in the cockpit.
4. It allows the backup electric pump to be placed at the lowest
point in the fuel system which should provide the best protection
against vapor lock.
5. When switching tanks the new tank can be turned on before the old
tank is shut off, guaranteeing a continuous flow of fuel.
6. A trivial one: If the plane is landed with an unbalanced fuel
load, both valves can be left on, equalizing the fuel load before the
next flight.
The disadvantage is that both valves could be inadvertently turned
on, which on a low-wing plane means that if one tank is run dry in
that condition the engine could draw air. In that case one fuel gage
would read empty and changing the fuel valve positions (shutting off
the empty tank) would correct the condition. Interestingly, my DAR
was skeptical about the arrangement, but was satisfied by the
placement of a placard "continuous operation on both tanks
prohibited." Conversely, my test pilot like the arrangement, saying
that for at least the first half tank the engine could be operated on
both, keeping the fuel load balanced (well, anyone that has had a
Cardinal would not be convinced that would happen). Why do high-wing
planes often have a "both" position? Probably because the fuel is
joined together at the bottom of the plane, several feet below the
tanks. One tank would have to run dry with the other pulling enough
vacuum to overcome maybe 4 feet of head pressure - very unlikely. A
low wing plane has nowhere to connect the tanks together except
essentially even with the bottom of the tanks. When one runs dry air
would immediately enter the engine.
Just my nickel's worth (inflation, you know)
Gary Casey
On Sep 11, 2006, at 11:55 PM, AeroElectric-List Digest Server wrote:
> George- "... an on/off valve on each
> tank introduces problems and complexity..."
>
> Boy, am I glad you wrote that! I completely missed the part about
> independent fuel valves. Kevin, besides all the good points George
> makes,
> and as someone pointed out a while back on one of these lists, you
> will
> only find a "BOTH" position on a fuel selector in a high wing
> single engine
> airplane. The low wing planes have left, right, and off. With a
> high wing
> plane, you will sometimes see quite an imbalance develop when
> drawing fuel
> from both tanks simultaneously, even with the head pressure caused
> by the
> tank location. This effect could be much greater in a low wing
> installation. If you had the ability to have both tanks plumbed to
> the
> engine at the same time, when one tank emptied you could suck air
> into the
> system. Obviously, this would not be good. I would definitely
> recommend
> against two fuel valves.
>
> Sorry for not catching that sooner-
>
> glen matejcek
Message 4
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Subject: | Fuel Pump Switch(es) |
Not switching the valve is also one of the advantages of the fuel pumps
in the wingroot method. In this case the lines are simply joined
together in a tee fitting before going to the on /off valve.
In this installation the valve is only turned off in the event of an
emergency, never in normal operation.
True there is pressurised fuel in the lines in the cockpit...Hopefully
in an off field landing one would remember to turn off the pumps.
With dead (roller vane FI pumps) pumps the amount of fuel that could
trickle through under gravity would be very small, certainly less than
the standard arrangement.
Incidently my FAA inspector looked very skeptical for a few minutes. Not
surpring this guy had built like 5 RV's and this was very different.
Thought my "goose was cooked" for a moment but he signed it off once he
understood the system.
Frank
________________________________
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Gary
Casey
Sent: Tuesday, September 12, 2006 7:16 AM
Subject: Re: AeroElectric-List: Fuel Pump Switch(es)
I might have missed some of the discussion, but the comment below seems
to be directed at the tank valving method - specifically whether to use
two separate fuel valves or one, with the recommendation to run all the
fuel through one valve. I chose to put two valves on mine for the
following reasons:
1. A single valve is a single point of failure - what if the handle
breaks off or the valve sticks? The most likely time for that to happen
is when one port is being closed off before the other opens (apparently
most or all fuel selectors go to "off" between right and left
positions). If it jams in this position all fuel is shut off. My
on-off valves are completely independent and controlled from their own
lever and cable. If one jams either open or shut the other is
unaffected.
2. The fuel can be shut off at the tank, not in the middle of the
cockpit. When both valves are shut off no fuel can enter the cockpit,
which would be reassuring in case of an off-airport landing.
3. It reduces the number of fuel fittings and therefore the number of
potential leak paths, especially in the cockpit.
4. It allows the backup electric pump to be placed at the lowest point
in the fuel system which should provide the best protection against
vapor lock.
5. When switching tanks the new tank can be turned on before the old
tank is shut off, guaranteeing a continuous flow of fuel.
6. A trivial one: If the plane is landed with an unbalanced fuel load,
both valves can be left on, equalizing the fuel load before the next
flight.
Message 5
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Subject: | Whelen Strobes Blowing Fuses |
--> AeroElectric-List message posted by: "Peter Braswell" <pbraswell@alterthought.com>
Bob et. al. -
No, this is a brand new install/system and has been exhibiting this behavior
from almost day 1.
I do have an inline amp meter that I can hook up in an attempt to see what
kind of current draw I'm actually getting. I agree with you guys that this
and looking for obvious "bad" things (bad switch, bad/faulty connections) is
probably the place to start.
And yes, you are right Bob, no fancy-smancy equipment in my toolshed as you
suggested :-)
Thanks!
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: Tuesday, September 12, 2006 8:49 AM
Subject: Re: AeroElectric-List: Whelen Strobes Blowing Fuses
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
--> <nuckollsr@cox.net>
At 09:01 PM 9/11/2006 -0400, you wrote:
>Gang,
>I've got a problem with my Whelen strobe system blowing a 10 amp fuse.
>
>I'm using a 10 amp mini-blade fuse which is blowing intermittently.
>The kit manufacturer as per the instructions, recommends a 10 amp fuse,
>but of course they allude to a 10 amp aircraft style reset-able fuse.
>I can seem to get the fuse to blow fairly regularly if I turn the
>strobes on and off in quick succession. The fuse will blow less
>reliably if I turn the strobes on prior to takeoff and just leave them on.
>
>My questions are these: Would there be any difference in a 10 amp blade
>fuse vs. the mechanical breaker style fuse as prescribed by the
>manufacturer? And the other question is is there such thing as a
>slow-blow m
How old is this system? Is this a "new" phenomenon that's
popped up after a period of satisfactory operation or has
it existed from square-one? Have you placed an ammeter in
series with the supply line to measure the system's current
draw? You need an analog meter to get some notion of minimum
and maximum current between firings. Which strobe system is it?
>ini blade style fuse and could this possibly make a difference? And
>finally perhaps there is something more insidious at work here?
Fuses are faster to respond than most breakers. It could
be that your strobes are drawing an average well below
the 10A rating of the fuse but hit it repeatedly with
levels that exceed 10A and degrade the fuse over a period
of time.
The real definitive measurement would be to put a data acquisition
system on it and watch it for a period of time and the compare
that data with a system that performs as expected. Unfortunately,
most folks in your position don't have access to such equipment
and you're stuck with hip-shots hopefully filtered through some sense
of the physics.
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
Message 6
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Subject: | Whelen Strobes Blowing Fuses |
--> AeroElectric-List message posted by: "Matt Prather" <mprather@spro.net>
Is the mini blade fuse smaller than the regular ATC fuse (for which b and
c sells holders)?
Many amp meters are limited to 10A. If the trouble you are having is
blowing a 10A fuse, likely the circuit is drawing more than 10A. Be a
little careful here with the meter, though it's also likely fuse
protected.
As Bob has mentioned in the past, an analog meter often has faster
response time than many Digital MultiMeters (DMM). The quicker response
time can help in observing transient behavior in a circuit. It may be
quite a bit ea$ier to get an analog ammeter than it would be to get a more
sophisticated data acquistion system.
Dumb question: Is there anything else wired on the same 10A fuse circuit
(even though maybe it's turned off)?
If a device has much input capacitance (power supply caps), turning the
device on can cause a significant above-steady-state current draw - to
charge the caps. Power cycling the device repeatedly can generate higher
average current.
Regards,
Matt-
> --> AeroElectric-List message posted by: "Peter Braswell"
> <pbraswell@alterthought.com>
>
>
> Bob et. al. -
> No, this is a brand new install/system and has been exhibiting this
> behavior
> from almost day 1.
>
> I do have an inline amp meter that I can hook up in an attempt to see what
> kind of current draw I'm actually getting. I agree with you guys that
> this
> and looking for obvious "bad" things (bad switch, bad/faulty connections)
> is
> probably the place to start.
>
> And yes, you are right Bob, no fancy-smancy equipment in my toolshed as
> you
> suggested :-)
>
> Thanks!
> 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: Tuesday, September 12, 2006 8:49 AM
> To: aeroelectric-list@matronics.com
> Subject: Re: AeroElectric-List: Whelen Strobes Blowing Fuses
>
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> --> <nuckollsr@cox.net>
>
> At 09:01 PM 9/11/2006 -0400, you wrote:
>
>>Gang,
>>I've got a problem with my Whelen strobe system blowing a 10 amp fuse.
>>
>>I'm using a 10 amp mini-blade fuse which is blowing intermittently.
>>The kit manufacturer as per the instructions, recommends a 10 amp fuse,
>>but of course they allude to a 10 amp aircraft style reset-able fuse.
>>I can seem to get the fuse to blow fairly regularly if I turn the
>>strobes on and off in quick succession. The fuse will blow less
>>reliably if I turn the strobes on prior to takeoff and just leave them
>> on.
>>
>>My questions are these: Would there be any difference in a 10 amp blade
>>fuse vs. the mechanical breaker style fuse as prescribed by the
>>manufacturer? And the other question is is there such thing as a
>>slow-blow m
>
> How old is this system? Is this a "new" phenomenon that's
> popped up after a period of satisfactory operation or has
> it existed from square-one? Have you placed an ammeter in
> series with the supply line to measure the system's current
> draw? You need an analog meter to get some notion of minimum
> and maximum current between firings. Which strobe system is it?
>
>>ini blade style fuse and could this possibly make a difference? And
>>finally perhaps there is something more insidious at work here?
>
> Fuses are faster to respond than most breakers. It could
> be that your strobes are drawing an average well below
> the 10A rating of the fuse but hit it repeatedly with
> levels that exceed 10A and degrade the fuse over a period
> of time.
>
> The real definitive measurement would be to put a data acquisition
> system on it and watch it for a period of time and the compare
> that data with a system that performs as expected. Unfortunately,
> most folks in your position don't have access to such equipment
> and you're stuck with hip-shots hopefully filtered through some sense
> of the physics.
>
> Bob . . .
>
>
> ---------------------------------------------------------
> < What is so wonderful about scientific truth...is that >
> < the authority which determines whether there can be >
> < debate or not does not reside in some fraternity of >
> < scientists; nor is it divine. The authority rests >
> < with experiment. >
> < --Lawrence M. Krauss >
> ---------------------------------------------------------
>
>
Message 7
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Subject: | Whelen Strobes Blowing Fuses |
--> AeroElectric-List message posted by: "Peter Braswell" <pbraswell@alterthought.com>
Matt,
Thank you very much for the input.
I probably need to offer a amendment/correction to my earlier post, prompted
by one of your questions. I perhaps may have mis-named what I'm using. I
AM using a 10a ATC fuse. I purchased an assorted tray of them from Stein
Air. Sorry for the confusion.
Also, I do not have anything else on that circuit. I tried very hard (and
succeeded) to have one device/one fuse.
Peter
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Matt
Prather
Sent: Tuesday, September 12, 2006 11:49 AM
Subject: RE: AeroElectric-List: Whelen Strobes Blowing Fuses
--> AeroElectric-List message posted by: "Matt Prather"
--> <mprather@spro.net>
Is the mini blade fuse smaller than the regular ATC fuse (for which b and c
sells holders)?
Many amp meters are limited to 10A. If the trouble you are having is
blowing a 10A fuse, likely the circuit is drawing more than 10A. Be a
little careful here with the meter, though it's also likely fuse protected.
As Bob has mentioned in the past, an analog meter often has faster response
time than many Digital MultiMeters (DMM). The quicker response time can
help in observing transient behavior in a circuit. It may be quite a bit
ea$ier to get an analog ammeter than it would be to get a more sophisticated
data acquistion system.
Dumb question: Is there anything else wired on the same 10A fuse circuit
(even though maybe it's turned off)?
If a device has much input capacitance (power supply caps), turning the
device on can cause a significant above-steady-state current draw - to
charge the caps. Power cycling the device repeatedly can generate higher
average current.
Regards,
Matt-
> --> AeroElectric-List message posted by: "Peter Braswell"
> <pbraswell@alterthought.com>
>
>
> Bob et. al. -
> No, this is a brand new install/system and has been exhibiting this
> behavior from almost day 1.
>
> I do have an inline amp meter that I can hook up in an attempt to see
> what kind of current draw I'm actually getting. I agree with you guys
> that this and looking for obvious "bad" things (bad switch, bad/faulty
> connections) is probably the place to start.
>
> And yes, you are right Bob, no fancy-smancy equipment in my toolshed
> as you suggested :-)
>
> Thanks!
> 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: Tuesday, September 12, 2006 8:49 AM
> To: aeroelectric-list@matronics.com
> Subject: Re: AeroElectric-List: Whelen Strobes Blowing Fuses
>
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> --> <nuckollsr@cox.net>
>
> At 09:01 PM 9/11/2006 -0400, you wrote:
>
>>Gang,
>>I've got a problem with my Whelen strobe system blowing a 10 amp fuse.
>>
>>I'm using a 10 amp mini-blade fuse which is blowing intermittently.
>>The kit manufacturer as per the instructions, recommends a 10 amp
>>fuse, but of course they allude to a 10 amp aircraft style reset-able
fuse.
>>I can seem to get the fuse to blow fairly regularly if I turn the
>>strobes on and off in quick succession. The fuse will blow less
>>reliably if I turn the strobes on prior to takeoff and just leave them
>>on.
>>
>>My questions are these: Would there be any difference in a 10 amp
>>blade fuse vs. the mechanical breaker style fuse as prescribed by the
>>manufacturer? And the other question is is there such thing as a
>>slow-blow m
>
> How old is this system? Is this a "new" phenomenon that's
> popped up after a period of satisfactory operation or has
> it existed from square-one? Have you placed an ammeter in
> series with the supply line to measure the system's current
> draw? You need an analog meter to get some notion of minimum
> and maximum current between firings. Which strobe system is it?
>
>>ini blade style fuse and could this possibly make a difference? And
>>finally perhaps there is something more insidious at work here?
>
> Fuses are faster to respond than most breakers. It could
> be that your strobes are drawing an average well below
> the 10A rating of the fuse but hit it repeatedly with
> levels that exceed 10A and degrade the fuse over a period
> of time.
>
> The real definitive measurement would be to put a data acquisition
> system on it and watch it for a period of time and the compare
> that data with a system that performs as expected. Unfortunately,
> most folks in your position don't have access to such equipment
> and you're stuck with hip-shots hopefully filtered through some sense
> of the physics.
>
> Bob . . .
>
>
> ---------------------------------------------------------
> < What is so wonderful about scientific truth...is that >
> < the authority which determines whether there can be >
> < debate or not does not reside in some fraternity of >
> < scientists; nor is it divine. The authority rests >
> < with experiment. >
> < --Lawrence M. Krauss >
> ---------------------------------------------------------
>
>
Message 8
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|
Subject: | Re: Fuel Pump Switch(es)Fuel Pump Switch(es)Fuel Pump |
Switch(es)
My $.02.
Electrically dependent planes with two pumps need a dedicated switch for
each pump drawing from independent power sources.
FWIW, I am using an EFI on my 6cyl Franklin in a Glasair TD and have
spent a lot of hours thinking about my fuel system. As fuel starvation
seems to be the most common cause of engine stoppage, and that my 58
year old ADD noggin sometimes trys to kill me, I wanted a system that
was as idiot proof as possible. That meant not having to remember to
switch tanks, that all fuel in the system goes to the intake of the
pumps no matter what I do. All I have to remember is to turn on the
pump(s) when I start the engine. I have a fool proof reminder to do
that, when the engine won't start.
Fuel from my split tanks flows through one way umbrella valves to a
common sump,on the bottom of the wing and at the low point of the fuel
system. A header tank is also plumbed to the sump. All recirculated fuel
goes back to the header with an internal overflow well that will dump
the overflow back to the mains. Both pumps, (separate switches, to two
batteries), pointed aft, draw from the common sump. There is no R-L
selector valve, no shut off valve, as the Bosch aerotor pumps, each with
a built in check valve, do not flow fuel without power and the fuel
filter on the FW is higher than the sump . If I don't want fuel to flow
to the engine, I turn off a switch. There is an on-off valve for the
header tank so that I can allow the header to be refilled from
recirculated fuel to use for landings and TO's (more head on the pump
intakes), however if I forget to turn this on, and the tank fills, it
will overflow back to the mains.
As long as their is fuel on board, it will flow to the pump intakes,
mental incapacitation of the pilot notwithstanding.
Message 9
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Subject: | Whelen Strobes Blowing Fuses |
--> AeroElectric-List message posted by: "james wickert" <jimw_btg@earthlink.net>
Food for thought a full strobe system can draw from 7 A for the Whelen
A413A HDA-CF at 14 Volts to as low as 1.7A with the A409ATS CF at 14 volts.
If you have a 7A operating unit when you turn it on it could I believe when
loading up the capacitors to fire the 4kv trigger coil and provide the 250v
anode to cathode current....I am not sure if it would surge the load to
over 10 Amps?
Jim Wickert
Vision CorvAir #159
> [Original Message]
> From: Peter Braswell <pbraswell@alterthought.com>
> To: <aeroelectric-list@matronics.com>
> Date: 9/12/2006 11:17:56 AM
> Subject: RE: AeroElectric-List: Whelen Strobes Blowing Fuses
>
> --> AeroElectric-List message posted by: "Peter Braswell"
<pbraswell@alterthought.com>
>
>
> Matt,
> Thank you very much for the input.
>
> I probably need to offer a amendment/correction to my earlier post,
prompted
> by one of your questions. I perhaps may have mis-named what I'm using. I
> AM using a 10a ATC fuse. I purchased an assorted tray of them from Stein
> Air. Sorry for the confusion.
>
> Also, I do not have anything else on that circuit. I tried very hard (and
> succeeded) to have one device/one fuse.
>
> Peter
>
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Matt
> Prather
> Sent: Tuesday, September 12, 2006 11:49 AM
> To: aeroelectric-list@matronics.com
> Subject: RE: AeroElectric-List: Whelen Strobes Blowing Fuses
>
> --> AeroElectric-List message posted by: "Matt Prather"
> --> <mprather@spro.net>
>
> Is the mini blade fuse smaller than the regular ATC fuse (for which b and
c
> sells holders)?
>
> Many amp meters are limited to 10A. If the trouble you are having is
> blowing a 10A fuse, likely the circuit is drawing more than 10A. Be a
> little careful here with the meter, though it's also likely fuse
protected.
>
> As Bob has mentioned in the past, an analog meter often has faster
response
> time than many Digital MultiMeters (DMM). The quicker response time can
> help in observing transient behavior in a circuit. It may be quite a bit
> ea$ier to get an analog ammeter than it would be to get a more
sophisticated
> data acquistion system.
>
> Dumb question: Is there anything else wired on the same 10A fuse circuit
> (even though maybe it's turned off)?
>
> If a device has much input capacitance (power supply caps), turning the
> device on can cause a significant above-steady-state current draw - to
> charge the caps. Power cycling the device repeatedly can generate higher
> average current.
>
>
> Regards,
>
> Matt-
>
> > --> AeroElectric-List message posted by: "Peter Braswell"
> > <pbraswell@alterthought.com>
> >
> >
> > Bob et. al. -
> > No, this is a brand new install/system and has been exhibiting this
> > behavior from almost day 1.
> >
> > I do have an inline amp meter that I can hook up in an attempt to see
> > what kind of current draw I'm actually getting. I agree with you guys
> > that this and looking for obvious "bad" things (bad switch, bad/faulty
> > connections) is probably the place to start.
> >
> > And yes, you are right Bob, no fancy-smancy equipment in my toolshed
> > as you suggested :-)
> >
> > Thanks!
> > 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: Tuesday, September 12, 2006 8:49 AM
> > To: aeroelectric-list@matronics.com
> > Subject: Re: AeroElectric-List: Whelen Strobes Blowing Fuses
> >
> > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> > --> <nuckollsr@cox.net>
> >
> > At 09:01 PM 9/11/2006 -0400, you wrote:
> >
> >>Gang,
> >>I've got a problem with my Whelen strobe system blowing a 10 amp fuse.
> >>
> >>I'm using a 10 amp mini-blade fuse which is blowing intermittently.
> >>The kit manufacturer as per the instructions, recommends a 10 amp
> >>fuse, but of course they allude to a 10 amp aircraft style reset-able
> fuse.
> >>I can seem to get the fuse to blow fairly regularly if I turn the
> >>strobes on and off in quick succession. The fuse will blow less
> >>reliably if I turn the strobes on prior to takeoff and just leave them
> >>on.
> >>
> >>My questions are these: Would there be any difference in a 10 amp
> >>blade fuse vs. the mechanical breaker style fuse as prescribed by the
> >>manufacturer? And the other question is is there such thing as a
> >>slow-blow m
> >
> > How old is this system? Is this a "new" phenomenon that's
> > popped up after a period of satisfactory operation or has
> > it existed from square-one? Have you placed an ammeter in
> > series with the supply line to measure the system's current
> > draw? You need an analog meter to get some notion of minimum
> > and maximum current between firings. Which strobe system is it?
> >
> >>ini blade style fuse and could this possibly make a difference? And
> >>finally perhaps there is something more insidious at work here?
> >
> > Fuses are faster to respond than most breakers. It could
> > be that your strobes are drawing an average well below
> > the 10A rating of the fuse but hit it repeatedly with
> > levels that exceed 10A and degrade the fuse over a period
> > of time.
> >
> > The real definitive measurement would be to put a data acquisition
> > system on it and watch it for a period of time and the compare
> > that data with a system that performs as expected. Unfortunately,
> > most folks in your position don't have access to such equipment
> > and you're stuck with hip-shots hopefully filtered through some
sense
> > of the physics.
> >
> > Bob . . .
> >
> >
> > ---------------------------------------------------------
> > < What is so wonderful about scientific truth...is that >
> > < the authority which determines whether there can be >
> > < debate or not does not reside in some fraternity of >
> > < scientists; nor is it divine. The authority rests >
> > < with experiment. >
> > < --Lawrence M. Krauss >
> > ---------------------------------------------------------
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
>
Message 10
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Subject: | Re: AeroElectric-List Digest: 26 Msgs - 09/10/06 |
In a forum such as this, you really need to be sure of your answer
before you post one.
That's for damn sure!
Stan Sutterfield
Do not archive
Message 11
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Subject: | Re: Alternator Problem - Not in plane |
--> AeroElectric-List message posted by: Bob White <bob@bob-white.com>
On Sun, 10 Sep 2006 07:34:43 EDT
FLYaDIVE@aol.com wrote:
> --> AeroElectric-List message posted by: FLYaDIVE@aol.com
>
> In a message dated 9/9/06 10:54:08 AM Eastern Daylight Time,
> ceengland@bellsouth.net writes:
>
> > If they came off small cars, they might not be rated for that much
> > current & unable to maintain voltage if you demand excess current.
> >
> > Another thought: are they internally or externally regulated? If
> > external & you're using a regulator built into the test set, are you
> > sure the test set regulator is set correctly and are you sure the test
> > set voltmeter is accurate? Getting the same volt reading for all using
> > one test set & a different, same volt reading for all on another test
> > set seems to point at the test sets.
> ====================================
> Charlie:
>
> The rated amperage of the alternator is 90 Amps.
> Normal draw is about 15 Amps.
> It is internally regulated.
> The test benches are at automotive parts stores and rebuilding shops.
> At both locations, on all 4 alternators the output was 10.5 V.
>
> This is a crazy problem. It is not a simple problem. I know there is
> someone out there with the knowledge and past experience of this situation.
If is
> was simple I would have solved it months ago. NO ONE has been able to identify
> the problem. Not even Hyundai or Bosch. And it is their alternator's!
>
>
> Barry
> "Chop'd Liver"
>
Hi Barry,
I've been thinking about your alternator problem. I wonder if it could
be as simple as having a bit of series resistance between the
alternator and the voltmeter. At 90 amps, you only need 0.04 to 0.05
ohms to see that kind of voltage drop. Test equipment I've seen at
parts stores have a big clips to connect to the alternator and I could
easily imagine having that much resistance in the connections.
Particularly with 90 amps running through them. The fact that the
voltage varied from 10.5 V to 12.2 V with a different tester is an
indication of that kind of problem. (Or the voltmeters aren't very
accurate.)
If possible, try the test with a voltmeter connected directly to the B
lead and alternator case so that none of the test current is flowing in
the leads to the voltmeter.
Bob W.
--
http://www.bob-white.com
N93BD - Rotary Powered BD-4 (first engine start 1/7/06)
Custom Cables for your rotary installation -
http://www.roblinphoto.com/shop/
Message 12
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Subject: | Whelen Strobes Blowing Fuses |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 12:03 PM 9/12/2006 -0400, you wrote:
>--> AeroElectric-List message posted by: "Peter Braswell"
><pbraswell@alterthought.com>
>
>
>Matt,
>Thank you very much for the input.
>
>I probably need to offer a amendment/correction to my earlier post, prompted
>by one of your questions. I perhaps may have mis-named what I'm using. I
>AM using a 10a ATC fuse. I purchased an assorted tray of them from Stein
>Air. Sorry for the confusion.
>
>Also, I do not have anything else on that circuit. I tried very hard (and
>succeeded) to have one device/one fuse.
>
>Peter
Okay. Just for grins, put a 15A fuse in and see what happens.
15A is not so much greater as to put the wire in danger. I presume
the strobe is running normally when the fuse is not blown. The
15A fuse experiment will help us put a crude bound on the
incoming current and at least show that it's not a transient
hard fault which will blow the 15A fuse too
Bob . . .
Message 13
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|
Subject: | Re: Fuel Pump Switch(es) |
--> AeroElectric-List message posted by: Kevin Horton <khorton01@rogers.com>
On 12 Sep 2006, at 10:15, Gary Casey wrote:
> I might have missed some of the discussion, but the comment below
> seems to be directed at the tank valving method - specifically
> whether to use two separate fuel valves or one, with the
> recommendation to run all the fuel through one valve. I chose to
> put two valves on mine for the following reasons:
>
> 1. A single valve is a single point of failure - what if the
> handle breaks off or the valve sticks? The most likely time for
> that to happen is when one port is being closed off before the
> other opens (apparently most or all fuel selectors go to "off"
> between right and left positions). If it jams in this position all
> fuel is shut off. My on-off valves are completely independent and
> controlled from their own lever and cable. If one jams either open
> or shut the other is unaffected.
> 2. The fuel can be shut off at the tank, not in the middle of the
> cockpit. When both valves are shut off no fuel can enter the
> cockpit, which would be reassuring in case of an off-airport landing.
> 3. It reduces the number of fuel fittings and therefore the number
> of potential leak paths, especially in the cockpit.
> 4. It allows the backup electric pump to be placed at the lowest
> point in the fuel system which should provide the best protection
> against vapor lock.
> 5. When switching tanks the new tank can be turned on before the
> old tank is shut off, guaranteeing a continuous flow of fuel.
> 6. A trivial one: If the plane is landed with an unbalanced fuel
> load, both valves can be left on, equalizing the fuel load before
> the next flight.
>
> The disadvantage is that both valves could be inadvertently turned
> on, which on a low-wing plane means that if one tank is run dry in
> that condition the engine could draw air. In that case one fuel
> gage would read empty and changing the fuel valve positions
> (shutting off the empty tank) would correct the condition.
> Interestingly, my DAR was skeptical about the arrangement, but was
> satisfied by the placement of a placard "continuous operation on
> both tanks prohibited." Conversely, my test pilot like the
> arrangement, saying that for at least the first half tank the
> engine could be operated on both, keeping the fuel load balanced
> (well, anyone that has had a Cardinal would not be convinced that
> would happen). Why do high-wing planes often have a "both"
> position? Probably because the fuel is joined together at the
> bottom of the plane, several feet below the tanks. One tank would
> have to run dry with the other pulling enough vacuum to overcome
> maybe 4 feet of head pressure - very unlikely. A low wing plane
> has nowhere to connect the tanks together except essentially even
> with the bottom of the tanks. When one runs dry air would
> immediately enter the engine.
You are worried about fuel valve handles breaking. With your design,
what happens if you have run one tank down low, want to switch to the
other tank, and the valve handle on the tank that is feeding breaks
so you can't close that valve? Won't the engine quit once that tank
is empty and the engine starts sucking air? How is this better than
a valve handle failure with the normal design?
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
Message 14
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Subject: | Whelen Strobes Blowing Fuses |
--> AeroElectric-List message posted by: "Peter Braswell" <pbraswell@alterthought.com>
Bob,
Easy enough to do! I'll give it a whirl and see what happens. And to
answer your question, yes the strobe work fine when it is working.
Thanks!
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: Tuesday, September 12, 2006 9:11 PM
Subject: RE: AeroElectric-List: Whelen Strobes Blowing Fuses
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
--> <nuckollsr@cox.net>
At 12:03 PM 9/12/2006 -0400, you wrote:
>--> AeroElectric-List message posted by: "Peter Braswell"
><pbraswell@alterthought.com>
>
>
>Matt,
>Thank you very much for the input.
>
>I probably need to offer a amendment/correction to my earlier post,
>prompted by one of your questions. I perhaps may have mis-named what
>I'm using. I AM using a 10a ATC fuse. I purchased an assorted tray of
>them from Stein Air. Sorry for the confusion.
>
>Also, I do not have anything else on that circuit. I tried very hard
>(and
>succeeded) to have one device/one fuse.
>
>Peter
Okay. Just for grins, put a 15A fuse in and see what happens.
15A is not so much greater as to put the wire in danger. I presume
the strobe is running normally when the fuse is not blown. The
15A fuse experiment will help us put a crude bound on the
incoming current and at least show that it's not a transient
hard fault which will blow the 15A fuse too
Bob . . .
Message 15
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Subject: | Whelen Strobes Blowing Fuses |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 09:49 AM 9/12/2006 -0600, you wrote:
>--> AeroElectric-List message posted by: "Matt Prather" <mprather@spro.net>
>
>Is the mini blade fuse smaller than the regular ATC fuse (for which b and
>c sells holders)?
Interesting question. If he WAS using the ATM "mini" fuses, would
we expect it to be twitchy compared to it's larger brother. I uploaded
the spec sheets to:
http://www.aeroelectric.com/Mfgr_Data/Fuses_and_Current_Limiters/Bussman/ATC_Specs.pdf
and
http://www.aeroelectric.com/Mfgr_Data/Fuses_and_Current_Limiters/Bussman/ATC_Specs.pdf
I note that the "little guys" spec the same
headroom (ATM-3 ATC-3 fuses both go asymtotic
at 4A). At 10A, the ATM-3 average blow is about 140 mS
and the ATC-3 is 80 mS. I don't know if you were thinking
the same thing I was but in any case, it's interesting
to note that the smaller fuse has a bit more
thermo-dynamic mass than big brother. Who wuda thunk it?
>As Bob has mentioned in the past, an analog meter often has faster
>response time than many Digital MultiMeters (DMM). The quicker response
>time can help in observing transient behavior in a circuit. It may be
>quite a bit ea$ier to get an analog ammeter than it would be to get a more
>sophisticated data acquistion system.
One of the reasons I keep analog meters around is to
watch trends/dynamics of the parameter being observed.
A digital meter is difficult to get a sense of min/max,
duty cycle (stays high longer than low) and frequency.
Digitals may be giving be perfectly accurate data for each
time they take a reading (typically 1 to 4 times per second)
but one cannot deduce the behaviors cited from what appears
to be a dancing set of random numbers.
Many digital meters have a bar graph built in under the
digits but it's hard to beat the black pointer waving
across a white scale to get a sense of "the beat".
Bob . . .
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