Today's Message Index:
----------------------
1. 07:02 AM - Re: Calibrating fuel qty gauges (Johnson, Phillip (EXP))
2. 07:09 AM - Re: VOM Troubles (Robert L. Nuckolls, III)
3. 10:12 AM - Re: VOM Troubles (David E. Nelson)
4. 02:20 PM - electric system for round the world flight (David Posey)
5. 04:00 PM - Re: VOM Troubles - Datapoint (David E. Nelson)
6. 05:51 PM - Re: VOM Troubles (S. Ramirez)
7. 07:02 PM - Re: VOM Troubles (Dennis Johnson)
8. 07:37 PM - Checking Coil (philip smith)
9. 08:35 PM - Re: electric system for round the world flight (Walter Fellows)
10. 08:54 PM - Re: electric system for round the world flight (Robert L. Nuckolls, III)
11. 08:57 PM - Re: Checking Coil (Robert L. Nuckolls, III)
12. 09:25 PM - Re: Re: VOM Troubles (jerb)
Message 1
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Subject: | Re: Calibrating fuel qty gauges |
Was Said>
The Princeton Capacitance Sensors I bought and connected to the AF-3400
EM do not work. I've calibrated them 7 times and they still fluctuate
between full and 8 gallons when the tanks are full and fluctuate wildly
when less than full. Perhaps I've done something wrong in the
calibration - I know most errors are installation or operator errors -
but, I tried to follow the AF-3400 instructions accurately.<end
When I installed my capacitance senders I seem to remember having to
drill a small hole at the highest point so that the fuel could drain
back down the tube as necessary. It is possible that you have entrapped
fuel in the tube that is being held there and needs to be released by a
small vent.
Regards,
Phillip Johnson
Message 2
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Subject: | Re: VOM Troubles |
At 05:25 PM 8/16/2009, you wrote:
><pinetownd@volcano.net>
>
>I have a Fluke model 87 digital VOM (Volt-Ohm-Milliammeter) that has
>just started discharging the internal 9 volt battery in less than a
>month while it is turned OFF. I've had this meter for 15 years and
>used it throughout building my airplane, as well as various hobbies
>before that, so I guess I got my money's worth out of it, but I'm puzzled.
Great instrument. I've had one since they came
on the market.
>Using another meter, I measured about 10 microamps current out of
>the Fluke's internal 9 volt transistor radio battery while it's
>turned OFF. If a 9 volt transistor radio battery holds 0.5
>amp-hours, then with 10 microamps, the battery should last 50,000
>hours. But the last two batteries lasted about a month each. They
>test good before I put them in and have an expiration date of 2013.
Emacs!
A Duracell 9v has published performance data as shown
above. The smallest discharge curve is for 2 ma
so with a end of life voltage of say 7 volts, yes
the device should deliver 500 mAh of service at
2 mA and MORE at still smaller drains. The internal
resistance of the battery becomes less significant
as current demands drop . . .
>First, is my arithmetic correct? I think a milliamp is 0.001 amps
>and a microamp is 0.000001 amps. I think a 10 microamp current
>through a half amp-hour battery would take 50,000 hours to deplete the battery.
Yup, that's about right.
>
>
>Second, did I read my digital VOM correctly? Using a nice German
>BBC VOM, set on the 2 milliamp scale, it reads .009. Using a cheap
>Harbor Freight digital VOM, set on the 200 microamp scale, it reads 09.5.
The interpretation of your observations seems
correct.
>You can see that something is wrong, either with my math or the way
>I'm reading the scale on the VOMs. Or maybe the Duracell fairies
>are sneaking in and sucking all the juice out of my batteries?
>
>I talked to Fluke customer support and he said there was no
>published spec on the current draw from the battery while it was
>turned off and couldn't say if mine was bad or not. My model 87
>isn't supported anymore and he wanted me to buy the new version.
My model 87 is 100 miles away right now
but I'll be back in that shop tomorrow or
Wednesday. I'll duplicate your experiment
so we can compare results. In the mean time,
perhaps someone else here on the List has
a model 87 Fluke and can do their own
investigation.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
Message 3
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Subject: | Re: VOM Troubles |
I've a Fluke 87 so I'll check it out this PM and report back.
/\/elson
~~ Lately my memory seems to be like a steel trap .... without any spring. ~~
On Mon, 17 Aug 2009, Robert L. Nuckolls, III wrote:
> At 05:25 PM 8/16/2009, you wrote:
>
> I have a Fluke model 87 digital VOM (Volt-Ohm-Milliammeter) that has just
started discharging the internal 9 volt battery in less than a month while
it is turned OFF. I've had this
> meter for 15 years and used it throughout building my airplane, as well
as various hobbies before that, so I guess I got my money's worth out of it,
but I'm puzzled.
>
>
> Great instrument. I've had one since they came
> on the market.
>
> Using another meter, I measured about 10 microamps current out of the Fluke's
internal 9 volt transistor radio battery while it's turned OFF. If a 9
volt transistor radio battery
> holds 0.5 amp-hours, then with 10 microamps, the battery should last 50,000
hours. But the last two batteries lasted about a month each. They test
good before I put them in and
> have an expiration date of 2013.
>
>
> Emacs!
>
> A Duracell 9v has published performance data as shown
> above. The smallest discharge curve is for 2 ma
> so with a end of life voltage of say 7 volts, yes
> the device should deliver 500 mAh of service at
> 2 mA and MORE at still smaller drains. The internal
> resistance of the battery becomes less significant
> as current demands drop . . .
>
> First, is my arithmetic correct? I think a milliamp is 0.001 amps and
a microamp is 0.000001 amps. I think a 10 microamp current through a half amp-hour
battery would take 50,000
> hours to deplete the battery.
>
>
> Yup, that's about right.
>
>
> Second, did I read my digital VOM correctly? Using a nice German BBC VOM,
set on the 2 milliamp scale, it reads .009. Using a cheap Harbor Freight
digital VOM, set on the 200
> microamp scale, it reads 09.5.
>
>
> The interpretation of your observations seems
> correct.
>
>
> You can see that something is wrong, either with my math or the way I'm
reading the scale on the VOMs. Or maybe the Duracell fairies are sneaking in
and sucking all the juice out
> of my batteries?
>
> I talked to Fluke customer support and he said there was no published spec
on the current draw from the battery while it was turned off and couldn't
say if mine was bad or not. My
> model 87 isn't supported anymore and he wanted me to buy the new version.
>
>
> My model 87 is 100 miles away right now
> but I'll be back in that shop tomorrow or
> Wednesday. I'll duplicate your experiment
> so we can compare results. In the mean time,
> perhaps someone else here on the List has
> a model 87 Fluke and can do their own
> investigation.
>
> Bob . . .
>
> ---------------------------------------
> ( . . . a long habit of not thinking )
> ( a thing wrong, gives it a superficial )
> ( appearance of being right . . . )
> ( )
> ( -Thomas Paine 1776- )
> ---------------------------------------
>
>
>
Message 4
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Subject: | electric system for round the world flight |
Bob, I am assisting a friend with his RV8 that he will fly around the
world. Engine is Lyc O-360 (new) with fuel injection, oem alternator,
Vac pad B&C 8amp pm alternator, 2 batteries, one oem mag and one
Lightspeed electronic ignition. Panel will be typical glass stuff
w/autopilot, two axis. What are your recommendations for the electrical
system?
Message 5
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Subject: | Re: VOM Troubles - Datapoint |
I measured 7.2 uA for my Fluke 87.
/\/elson
~~ Lately my memory seems to be like a steel trap .... without any spring. ~~
On Mon, 17 Aug 2009, David E. Nelson wrote:
> <david.nelson@pobox.com>
>
>
> I've a Fluke 87 so I'll check it out this PM and report back.
>
> /\/elson
>
> ~~ Lately my memory seems to be like a steel trap .... without any spring.
> ~~
>
> On Mon, 17 Aug 2009, Robert L. Nuckolls, III wrote:
>
>> At 05:25 PM 8/16/2009, you wrote:
>> <pinetownd@volcano.net>
>>
>> I have a Fluke model 87 digital VOM (Volt-Ohm-Milliammeter) that has
>> just started discharging the internal 9 volt battery in less than a month
>> while it is turned OFF. I've had this
>> meter for 15 years and used it throughout building my airplane, as
>> well as various hobbies before that, so I guess I got my money's worth out
>> of it, but I'm puzzled.
>>
>>
>> Great instrument. I've had one since they came
>> on the market.
>>
>> Using another meter, I measured about 10 microamps current out of the
>> Fluke's internal 9 volt transistor radio battery while it's turned OFF. If
>> a 9 volt transistor radio battery
>> holds 0.5 amp-hours, then with 10 microamps, the battery should last
>> 50,000 hours. But the last two batteries lasted about a month each. They
>> test good before I put them in and
>> have an expiration date of 2013.
>>
>>
>> Emacs!
>>
>> A Duracell 9v has published performance data as shown
>> above. The smallest discharge curve is for 2 ma
>> so with a end of life voltage of say 7 volts, yes
>> the device should deliver 500 mAh of service at
>> 2 mA and MORE at still smaller drains. The internal
>> resistance of the battery becomes less significant
>> as current demands drop . . .
>>
>> First, is my arithmetic correct? I think a milliamp is 0.001 amps
>> and a microamp is 0.000001 amps. I think a 10 microamp current through a
>> half amp-hour battery would take 50,000
>> hours to deplete the battery.
>>
>>
>> Yup, that's about right.
>>
>>
>> Second, did I read my digital VOM correctly? Using a nice German BBC
>> VOM, set on the 2 milliamp scale, it reads .009. Using a cheap Harbor
>> Freight digital VOM, set on the 200
>> microamp scale, it reads 09.5.
>>
>>
>> The interpretation of your observations seems
>> correct.
>>
>>
>> You can see that something is wrong, either with my math or the way
>> I'm reading the scale on the VOMs. Or maybe the Duracell fairies are
>> sneaking in and sucking all the juice out
>> of my batteries?
>>
>> I talked to Fluke customer support and he said there was no published
>> spec on the current draw from the battery while it was turned off and
>> couldn't say if mine was bad or not. My
>> model 87 isn't supported anymore and he wanted me to buy the new
>> version.
>>
>>
>> My model 87 is 100 miles away right now
>> but I'll be back in that shop tomorrow or
>> Wednesday. I'll duplicate your experiment
>> so we can compare results. In the mean time,
>> perhaps someone else here on the List has
>> a model 87 Fluke and can do their own
>> investigation.
>>
>> Bob . . .
>>
>> ---------------------------------------
>> ( . . . a long habit of not thinking )
>> ( a thing wrong, gives it a superficial )
>> ( appearance of being right . . . )
>> ( )
>> ( -Thomas Paine 1776- )
>> ---------------------------------------
>>
>>
>>
>
>
Message 6
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Dennis, your math is correct. You will get 50,000 hrs out of a 0.5 Amp-Hr
battery at 10 uA. I took my trusty Fluke 87 into work today to have its
battery current measured. It was 7.9 uA. There is something wrong with
your meter. I'm guessing one of the components has failed or there is FOD
somewhere causing low resistance.
If it is FOD, possibly you can solve it by cleaning the PWB or the rotary
switch. This particular problem may be exacerbated by the auto-turn off
feature, which is controlled by a microcontroller. The reason is because a
FOD can cause a small amount of current to flow in the right place and tell
the microcontroller to turn the whole meter on and keep it on. It may be
worth it to blow clean both the PWB and the rotary switch and then retest
it.
I've had this meter since the 1980s, and I'd hate to see it go. It's a
really good meter!
Good luck.
Simon Ramirez
Copyright 2009
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Dennis
Johnson
Sent: Sunday, August 16, 2009 6:25 PM
Subject: AeroElectric-List: VOM Troubles
<pinetownd@volcano.net>
I have a Fluke model 87 digital VOM (Volt-Ohm-Milliammeter) that has just
started discharging the internal 9 volt battery in less than a month while
it is turned OFF. I've had this meter for 15 years and used it throughout
building my airplane, as well as various hobbies before that, so I guess I
got my money's worth out of it, but I'm puzzled.
Using another meter, I measured about 10 microamps current out of the
Fluke's internal 9 volt transistor radio battery while it's turned OFF. If
a 9 volt transistor radio battery holds 0.5 amp-hours, then with 10
microamps, the battery should last 50,000 hours. But the last two batteries
lasted about a month each. They test good before I put them in and have an
expiration date of 2013.
First, is my arithmetic correct? I think a milliamp is 0.001 amps and a
microamp is 0.000001 amps. I think a 10 microamp current through a half
amp-hour battery would take 50,000 hours to deplete the battery.
Second, did I read my digital VOM correctly? Using a nice German BBC VOM,
set on the 2 milliamp scale, it reads .009. Using a cheap Harbor Freight
digital VOM, set on the 200 microamp scale, it reads 09.5.
You can see that something is wrong, either with my math or the way I'm
reading the scale on the VOMs. Or maybe the Duracell fairies are sneaking
in and sucking all the juice out of my batteries?
I talked to Fluke customer support and he said there was no published spec
on the current draw from the battery while it was turned off and couldn't
say if mine was bad or not. My model 87 isn't supported anymore and he
wanted me to buy the new version.
Any ideas?
Dennis Johnson
Lancair Legacy, 330 flight hours
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=258060#258060
Message 7
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Subject: | Re: VOM Troubles |
Thanks to Bob for confirming that my calculations weren't off by a few decimal
points. Thanks to Simon for measuring the current draw of his Fluke 87.
Simon's current draw, when turned off, was 7.9 micro amps. Mine was 9.5 micro
amps. So it seems like my meter is probably okay. I'll try blowing out dust
and I'll go with another new 9 volt battery and hope the gremlins leave me alone.
Could be a bad batch of 9 volt batteries? Still a puzzle.
Thanks, guys!
Dennis Johnson
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=258334#258334
Message 8
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Question - could say it's for an aircraft project - but can anybody tell me
how to ohm out a 12v ignition coil on my case tractor to see if its any
good.
Phil
CH-701 about done
Message 9
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Subject: | Re: electric system for round the world flight |
I flew a Cessna 210 from New York to Hawaii, Christmas Island and the Cooke
Islands and a return in 1984. This included many long overwater segments (up
to 14 hours). I was relatively inexperienced and encountered electrical
problems on the last leg from Hilo to San Jose partly at night. It turned
out to be a loose nut for the field wire at the alternator and it was
unnerving to watch the lights flicker for a few hours.
I would highly recommend Z-14. Even if he chooses not to have the long
overwater segments, getting repairs in remote places can be difficult and a
fully redundant system may well come in handy.
He should also not set out over water until he has flown the system for long
extended periods over land without constant radio communication to make sure
everything is working well. I choose the great plains from Indiana to
Colorado Springs, which can be traversed without crossing any real traffic
area. He also should have an HF or sat phone with proven ability to
communicate with ATC (ARINC and the the other controlling agencies). He
should also pay attention to survival, it is not that dangerous of a trip
for an experienced pilot who understands survival techniques.
Walter Fellows
On Mon, Aug 17, 2009 at 2:02 PM, David Posey
<dlposey-atlanta@earthlink.net>wrote:
> dlposey-atlanta@earthlink.net>
>
> Bob, I am assisting a friend with his RV8 that he will fly around the
> world. Engine is Lyc O-360 (new) with fuel injection, oem alternator, Vac
> pad B&C 8amp pm alternator, 2 batteries, one oem mag and one Lightspeed
> electronic ignition. Panel will be typical glass stuff w/autopilot, two
> axis. What are your recommendations for the electrical system?
>
>
Message 10
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Subject: | Re: electric system for round the world flight |
At 04:02 PM 8/17/2009, you wrote:
><dlposey-atlanta@earthlink.net>
>
>Bob, I am assisting a friend with his RV8 that he will fly around
>the world. Engine is Lyc O-360 (new) with fuel injection, oem
>alternator, Vac pad B&C 8amp pm alternator, 2 batteries, one oem mag
>and one Lightspeed electronic ignition. Panel will be typical glass
>stuff w/autopilot, two axis. What are your recommendations for the
>electrical system?
Figure Z-13/8 with Z-30 aux battery added
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
Message 11
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Subject: | Re: Checking Coil |
At 09:36 PM 8/17/2009, you wrote:
>Question - could say it's for an aircraft project - but can anybody
>tell me how to ohm out a 12v ignition coil on my case tractor to see
>if its any good.
Measure resistance between screw terminals and
look for 4-8 ohms. Measure between any screw termnial
and the tower (spark) terminal and you should see
perhaps 1000 ohms or more.
This only shows continuity and won't reveal shorted
turns . . . but since these things are generally
oil filled, shorted turns are unlikely.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
Message 12
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Subject: | Re: VOM Troubles |
Hey Guys,
Can't say about the batteries you have but the Duracells are not the
battery they used to be. You used to be able to put them into a
piece of equipment and not have to worry about them leaking, were
great for meters and cameras, not so any more. If I had to put my
finger on it I would say it started when they came out with their
more expensive (longer life) ultra's. Ever wonder what's inside a
Duracell battery, see the link below.
http://www.extremetech.com/article2/0,3973,1155268,00.asp
Sounds like your going to need a new Du-witcher - cost $150 bucks -
that's the thing the test leads plug into to.
Note, if you have a Duracell (alkaline) battery that has leaked,
clean it up best you can using white vinegar & Q--Tips for the tight
spots. Alkaline is a base - when it leaks it is quite aggressive and
can eat things up in a short time. It can be neutralized with a acid
which vinegar supplies.
jerb
At 07:00 PM 8/17/2009, you wrote:
><pinetownd@volcano.net>
>
>Thanks to Bob for confirming that my calculations weren't off by a
>few decimal points. Thanks to Simon for measuring the current draw
>of his Fluke 87.
>
>Simon's current draw, when turned off, was 7.9 micro amps. Mine was
>9.5 micro amps. So it seems like my meter is probably okay. I'll
>try blowing out dust and I'll go with another new 9 volt battery and
>hope the gremlins leave me alone. Could be a bad batch of 9 volt
>batteries? Still a puzzle.
>
>Thanks, guys!
>
>Dennis Johnson
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