Today's Message Index:
----------------------
1. 05:26 AM - Re: Radio interference (robintaylor)
2. 06:12 AM - How to test engine ground? (Dan Checkoway)
3. 07:22 AM - Re: How to test engine ground? (Bob McCallum)
4. 08:08 AM - Re: How to test engine ground? (Tim Andres)
5. 08:28 AM - Re: How to test engine ground? (Jeff Luckey)
6. 08:50 AM - Re: How to test engine ground? (Robert L. Nuckolls, III)
7. 09:00 AM - Re: How to test engine ground? (Dan Checkoway)
8. 09:02 AM - Re: How to test engine ground? (David Lloyd)
9. 09:13 AM - Re: How to test engine ground? (Dan Checkoway)
10. 09:37 AM - Re: How to test engine ground? (Mark Wesson)
11. 11:38 AM - Re: How to test engine ground? (Tim Andres)
12. 02:15 PM - Call for cover photos . . . (Robert L. Nuckolls, III)
13. 05:58 PM - Re: Re: Radio interference (Robert L. Nuckolls, III)
14. 10:47 PM - Re: Radio interference (robintaylor)
Message 1
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| Subject: | Re: Radio interference |
Thanks for the response Bob,
I had to wait until I flew again.
I am flying with twin Dynon Skyviews, as I turn each off, the noise progressively
reduces.
The frequency of the noise increases with the speed of the engine.
I have a common ground on the firewall that everything is connected to.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=399840#399840
Message 2
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| Subject: | How to test engine ground? |
This may seem like a ridiculous question, and hopefully I'll end up
slapping my forehead when I hear the answer...but here goes anyway.
I'd like to quantify, or at least qualify my engine ground connection.
That is, I have a 2 AWG wire connecting my engine to the ground block on
the firewall. Suffice it to say, I have reason to suspect that one of the
connections is less than perfect. I have an intermittent issue (probably
another thread in the making), and I want to rule out ground as a culprit.
When I throw an ohmmeter across, of course I see zero ohms. But that only
tells me the obvious. It would probably read zero even if I had a 24 AWG
wire in its place. :-) And what I'm concerned about is that maybe it's
reading zero despite the engine side connection not making good enough
contact. Probably not, but I'd like to rule it out.
Is there any way (something a doofus like me could do) to test the quality
of this engine ground connection? i.e. when my starter is sucking 200 amps
through that straw, I'd like to know if it's truly unimpeded so to speak.
Any tips or tricks? Or do we just trust that if the wire is fat enough, we
*think* our connections are fine, the starter cranks and nothing smokes,
then life is good enough?
Thanks,
Dan
Message 3
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| Subject: | How to test engine ground? |
Dan=3B
Connect your voltmeter between the battery negative post and the engine cas
e/starter housing while cranking and see what the voltage drop is. Very low
voltage reading = good ground. significant voltage reading = bad groun
d. If you also know what current you're drawing you can calculate total loo
p resistance using these readings.
Bob McC
Subject: AeroElectric-List: How to test engine ground?
From: dcheckoway@gmail.com
This may seem like a ridiculous question=2C and hopefully I'll end up slapp
ing my forehead when I hear the answer...but here goes anyway.
I'd like to quantify=2C or at least qualify my engine ground connection. T
hat is=2C I have a 2 AWG wire connecting my engine to the ground block on t
he firewall. Suffice it to say=2C I have reason to suspect that one of the
connections is less than perfect. I have an intermittent issue (probably
another thread in the making)=2C and I want to rule out ground as a culprit
.
=0A
=0A
When I throw an ohmmeter across=2C of course I see zero ohms. But that onl
y tells me the obvious. It would probably read zero even if I had a 24 AWG
wire in its place. :-) And what I'm concerned about is that maybe it's r
eading zero despite the engine side connection not making good enough conta
ct. Probably not=2C but I'd like to rule it out.
=0A
=0A
Is there any way (something a doofus like me could do) to test the quality
of this engine ground connection? i.e. when my starter is sucking 200 amps
through that straw=2C I'd like to know if it's truly unimpeded so to speak
.
=0A
=0A
Any tips or tricks? Or do we just trust that if the wire is fat enough=2C
we *think* our connections are fine=2C the starter cranks and nothing smoke
s=2C then life is good enough?
Thanks=2C
Dan
=0A
=0A
=0A
=0A
============0A
============0A
============0A
============0A
=0A
Message 4
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| Subject: | Re: How to test engine ground? |
Dans idea is a good one, but I think he meant misspoke slightly when he said
"voltage drop". You want to know the voltage between the engine case and th
e NEG battery terminal while cranking, in other words your volt meter is pla
ced in parallel with the ground system. Anything more than 1~1-1/2 volts ind
icates the ground is not able to drain off the ohm-bugs fast enough and they
are having to wait in line to get home :-). Also if you do have a high read
ing (high resistance) you can then go point to point on the different termi
nals and find the one causing the problem.
Tim
Sent from my iPad
On May 2, 2013, at 7:22 AM, Bob McCallum <robert.mccallum2@sympatico.ca> wro
te:
> Dan;
>
> Connect your voltmeter between the battery negative post and the engine ca
se/starter housing while cranking and see what the voltage drop is. Very low
voltage reading = good ground. significant voltage reading = bad ground
. If you also know what current you're drawing you can calculate total loop r
esistance using these readings.
>
> Bob McC
>
>
> Date: Thu, 2 May 2013 09:11:41 -0400
> Subject: AeroElectric-List: How to test engine ground?
> From: dcheckoway@gmail.com
> To: aeroelectric-list@matronics.com
>
> This may seem like a ridiculous question, and hopefully I'll end up slappi
ng my forehead when I hear the answer...but here goes anyway.
>
> I'd like to quantify, or at least qualify my engine ground connection. Th
at is, I have a 2 AWG wire connecting my engine to the ground block on the f
irewall. Suffice it to say, I have reason to suspect that one of the connec
tions is less than perfect. I have an intermittent issue (probably another t
hread in the making), and I want to rule out ground as a culprit.
>
> When I throw an ohmmeter across, of course I see zero ohms. But that only
tells me the obvious. It would probably read zero even if I had a 24 AWG w
ire in its place. :-) And what I'm concerned about is that maybe it's read
ing zero despite the engine side connection not making good enough contact.
Probably not, but I'd like to rule it out.
>
> Is there any way (something a doofus like me could do) to test the quality
of this engine ground connection? i.e. when my starter is sucking 200 amps
through that straw, I'd like to know if it's truly unimpeded so to speak.
>
> Any tips or tricks? Or do we just trust that if the wire is fat enough, w
e *think* our connections are fine, the starter cranks and nothing smokes, t
hen life is good enough?
>
> Thanks,
> Dan
>
>
> ==========
> -List" target="_blank">http://www.matronics.com/Navigator?AeroElectric-L
ist
> ==========
> http://forums.matronics.com
> ==========
> ="_blank">http://www.matronics.com/contribution
> ==========
>
>
>
==========================
=========
==========================
=========
==========================
=========
==========================
=========
>
Message 5
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| Subject: | Re: How to test engine ground? |
Tim , Bob's use of the term "Voltage Drop" is correct.
--- On Thu, 5/2/13, Tim Andres <tim2542@sbcglobal.net> wrote:
From: Tim Andres <tim2542@sbcglobal.net>
Subject: Re: AeroElectric-List: How to test engine ground?
Dans idea is a good one, but I think he meant misspoke slightly when he sai
d "voltage drop". You want to know the voltage between the engine case and
the NEG battery terminal while cranking, in other words your volt meter is
placed in parallel with the ground system. Anything more than 1~1-1/2 volts
indicates the ground is not able to drain off the ohm-bugs fast enough and
they are having to wait in line to get home :-). Also if you do have a hig
h reading (high resistance) -you can then go point to point on the differ
ent terminals and find the one causing the problem.-Tim
Sent from my iPad
On May 2, 2013, at 7:22 AM, Bob McCallum <robert.mccallum2@sympatico.ca> wr
ote:
=0A=0A=0ADan;
Connect your voltmeter between the battery negative post and the engine cas
e/starter housing while cranking and see what the voltage drop is. Very low
voltage reading = good ground. significant voltage reading = bad groun
d. If you also know what current you're drawing you can calculate total loo
p resistance using these readings.
Bob McC
Subject: AeroElectric-List: How to test engine ground?
From: dcheckoway@gmail.com
This may seem like a ridiculous question, and hopefully I'll end up slappin
g my forehead when I hear the answer...but here goes anyway.
I'd like to quantify, or at least qualify my engine ground connection.- T
hat is, I have a 2 AWG wire connecting my engine to the ground block on the
firewall.- Suffice it to say, I have reason to suspect that one of the c
onnections is less than perfect.- I have an intermittent issue (probably
another thread in the making), and I want to rule out ground as a culprit.
=0A=0A
When I throw an ohmmeter across, of course I see zero ohms.- But that onl
y tells me the obvious.- It would probably read zero even if I had a 24 A
WG wire in its place.- :-)- And what I'm concerned about is that maybe
it's reading zero despite the engine side connection not making good enough
contact.- Probably not, but I'd like to rule it out.
=0A=0A
Is there any way (something a doofus like me could do) to test the quality
of this engine ground connection?- i.e. when my starter is sucking 200 am
ps through that straw, I'd like to know if it's truly unimpeded so to speak
.
=0A=0A
Any tips or tricks?- Or do we just trust that if the wire is fat enough,
we *think* our connections are fine, the starter cranks and nothing smokes,
then life is good enough?
Thanks,
Dan
=0A=0A=0A=0A-List" target="_blank">http://www.matronics.com/Navigator?Aer
oElectric-List=0Ahttp://forums.matronics.com=0A="_blank">http://www.matro
nics.com/contribution=0A=0A =0A=0A=0A=0A====
=======0Ast">http://www.matronics.com/Navigator?AeroElectric-Li
st=0A=======================
=============0Acs.com=0A=========
==0Amatronics.com/contribution=0A=============
=======================0A=0A=0A
======================0A=0A
Message 6
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| Subject: | How to test engine ground? |
I'd like to quantify, or at least qualify my engine ground
connection. That is, I have a 2 AWG wire connecting my engine to the
ground block on the firewall. Suffice it to say, I have reason to
suspect that one of the connections is less than perfect. I have an
intermittent issue (probably another thread in the making), and I
want to rule out ground as a culprit.
When I throw an ohmmeter across, of course I see zero ohms. But that
only tells me the obvious. It would probably read zero even if I had
a 24 AWG wire in its place. :-) And what I'm concerned about is
that maybe it's reading zero despite the engine side connection not
making good enough contact. Probably not, but I'd like to rule it out.
Your observation has roots in the ideas we've discussed in the past .
. . ideas for quantifying the quality of electrical connections and
components with very low resistance.
Is there any way (something a doofus like me could do) to test the
quality of this engine ground connection? i.e. when my starter is
sucking 200 amps through that straw, I'd like to know if it's truly
unimpeded so to speak.
Any tips or tricks? Or do we just trust that if the wire is fat
enough, we *think* our connections are fine, the starter cranks and
nothing smokes, then life is good enough?
One fact that goes favorably to your question is that a really POOR
joint or component will have a LOT of voltage drop with a
commensurate concentration of high energy dissipation. For example, a
common reason for alternators to be returned to B&C for repair is a
burned b-lead terminal that was so loose as to allow arcing and much
heat . . . the terminal melted. Some contactor failures present as a
valiant effort to maintain useful conductivity but with attendant
losses in the one volt or more range. 1 volt x 200 amps is 200 watts
. . . dumping that kind of energy into the small area of a degraded
contact heats things up rapidly and accelerates the failure. See
http://tinyurl.com/qmk6gm
Thanks,
Dan
At 09:22 AM 5/2/2013, you wrote:
Dan;
Connect your voltmeter between the battery negative post and the
engine case/starter housing while cranking and see what the voltage
drop is. Very low voltage reading = good ground. significant voltage
reading = bad ground. If you also know what current you're drawing
you can calculate total loop resistance using these readings.
Bob McC
This is a good beginning . . . unfortunately, starters make very poor
loads for the purpose of conducting diagnostics. Starter current is
directly related to load . . . which varies wildly as the engine
rotates through cylinder compression cycles. Taking a reading from a
digital display watching voltage drops generated by a starter motor
is difficult if not impossible. An analog meter will be a little
better but not by much. Measuring voltage drop across various
portions of the power loop under known load is fundamental to the
low-ohms adapter hardware and articles offered on the website. The
low-ohms adapter illustrated offers a maximum of 1 amp excitation
current. A bit low for measuring starter circuit drops with commonly
available instrumentation. One would LIKE to excite a path under
analysis with a steady 10 or even 100 amps. This isn't as hard as it
might seem.
The folks over at Harbor Freight offer this carbon pile load battery
tester which is capable of developing a reasonably steady state load
at 200 amps or more.
Emacs!
To use this device as a circuit quality tester, you need to wire it
to your airplane such that it REPLACES the starter as a load on the
system. This is BEST accomplished by adding short test-pigtails to
the ship's wiring such that the 'test clamps' do not connect to the
airplane's wiring. If these 'slip' or fail to make good contact
throughout the test effort, they might arc and damage parts of the
airplane. The BEST way to make these connections is to cut the clips
off the test cables leaving about a 6' pigtail on the clip. Install
ring terminals that can be used to bolt the cable back together later
thus restoring the original functionality of the tester. With the
clips 'unbolted' you can attach tester wires to the crankcase and the
starter power terminal. For this test, remove the jumper on the
starter's pinion gear engagement solenoid to disable the starter. You
might also wish to fabricate a hand held 'pickle switch' to energize
the ship's starter contactor. The lead wires for this piece of
equipment needs to be long enough so that you can control the load
from any place you're observing your voltmeter.
Now, you may need to enlist the help of someone to 'manage the load'
. . . tell your assistant to crank the load knob up to achieve the
desired test current, 100A is probably enough. With a little
practice, you can easily hold a test current to within 5 amps or so.
Now, as you probe various portions of the (+) or (-) starter circuit
with a voltmeter, you can hit the system with a test load likely to
produce useful readings for voltage drop on your plain-vanilla
multimeter . . . either digital or analog. Most off-the-shelf meters
have a 200 mV full scale reading. With voltmeter and pickle-switch in
hand, you can explore the cranking circuit in its entirety. Any
portion of the circuit with compromised integrity will probably
manifest with rather striking voltage drop. Your starter contactor is
an intermittent duty device; you want to make the readings rather quickly.
One of the future AEC products being considered is a processor based
integrator adapter for a digital voltmeter. The device would have two
inputs: one for voltage drop, the other for battery voltage. A very
rapid sampling of current (voltage drop) compared with excitation
voltage (battery terminal voltage) would be evaluated and integrated
over time such that a technician could analyze system integrity using
the engine's starter as a load.
In the mean time, you can modify the HF battery tester into a
steady-state load that will yield very useful data for evaluating the
integrity of your system's fat wire circuits.
Bob . . .
Message 7
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| Subject: | Re: How to test engine ground? |
Thanks guys, that makes total sense...will give it a shot! (sound of hand
slapping forehead)
Dan
On Thu, May 2, 2013 at 11:27 AM, Jeff Luckey <jluckey@pacbell.net> wrote:
> Tim , Bob's use of the term "Voltage Drop" is correct.
>
>
> --- On *Thu, 5/2/13, Tim Andres <tim2542@sbcglobal.net>* wrote:
>
>
> From: Tim Andres <tim2542@sbcglobal.net>
> Subject: Re: AeroElectric-List: How to test engine ground?
> To: "aeroelectric-list@matronics.com" <aeroelectric-list@matronics.com>
> Date: Thursday, May 2, 2013, 8:07 AM
>
> Dans idea is a good one, but I think he meant misspoke slightly when he
> said "voltage drop". You want to know the voltage between the engine case
> and the NEG battery terminal while cranking, in other words your volt meter
> is placed in parallel with the ground system. Anything more than 1~1-1/2
> volts indicates the ground is not able to drain off the ohm-bugs fast
> enough and they are having to wait in line to get home :-). Also if you do
> have a high reading (high resistance) you can then go point to point on
> the different terminals and find the one causing the problem.
> Tim
>
> Sent from my iPad
>
> On May 2, 2013, at 7:22 AM, Bob McCallum <robert.mccallum2@sympatico.ca<http://mc/compose?to=robert.mccallum2@sympatico.ca>>
> wrote:
>
> *Dan;
>
> Connect your voltmeter between the battery negative post and the engine
> case/starter housing while cranking and see what the voltage drop is. Very
> low voltage reading = good ground. significant voltage reading = bad
> ground. If you also know what current you're drawing you can calculate
> total loop resistance using these readings.
>
> Bob McC
> *
>
> ------------------------------
> Date: Thu, 2 May 2013 09:11:41 -0400
> Subject: AeroElectric-List: How to test engine ground?
> From: dcheckoway@gmail.com <http://mc/compose?to=dcheckoway@gmail.com>
> To: aeroelectric-list@matronics.com<http://mc/compose?to=aeroelectric-list@matronics.com>
>
> This may seem like a ridiculous question, and hopefully I'll end up
> slapping my forehead when I hear the answer...but here goes anyway.
>
> I'd like to quantify, or at least qualify my engine ground connection.
> That is, I have a 2 AWG wire connecting my engine to the ground block on
> the firewall. Suffice it to say, I have reason to suspect that one of the
> connections is less than perfect. I have an intermittent issue (probably
> another thread in the making), and I want to rule out ground as a culprit.
>
> When I throw an ohmmeter across, of course I see zero ohms. But that only
> tells me the obvious. It would probably read zero even if I had a 24 AWG
> wire in its place. :-) And what I'm concerned about is that maybe it's
> reading zero despite the engine side connection not making good enough
> contact. Probably not, but I'd like to rule it out.
>
> Is there any way (something a doofus like me could do) to test the quality
> of this engine ground connection? i.e. when my starter is sucking 200 amps
> through that straw, I'd like to know if it's truly unimpeded so to speak.
>
> Any tips or tricks? Or do we just trust that if the wire is fat enough,
> we *think* our connections are fine, the starter cranks and nothing smokes,
> then life is good enough?
>
> Thanks,
> Dan
>
> *
>
> -List" target="_blank">http://www.matronics.com/Navigator?AeroElectric-Listhttp://forums.matronics.com
> ="_blank">http://www.matronics.com/contribution
> *
>
> *
>
> ==================================
> st">http://www.matronics.com/Navigator?AeroElectric-List
> ===================================cs.com
> ===================================matronics.com/contribution
> =========
> *
>
> *
>
> ank" href="http://www.matronics.com/Navigator?AeroElectric-List">http://wt; http://www.matronics.com/contrib==============
> <http://forums.matronics.co=>*
>
> *
>
> *
>
>
Message 8
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| Subject: | Re: How to test engine ground? |
Key words in Bob's answer are "post" and "starter housing"; where the
test instrument probes for voltage connection must be made. Don't test
at any point on the cable(s).
You want the test for loss to include all of the cable-to-terminal
connections. There could be corrosion, oxidation, looseness in those
cable joints that are invisible, but, will show up in the test Bob
outlines. If a voltage (loss) is found in that pathway somewhere, then,
you can switch your test leads and march down the cable length to track
down where the loss, cable resistance, is located and fix it.
....Dave
-------------------------------------------------------------------------
-------
----- Original Message -----
From: Bob McCallum
To: aeroelectric-list@matronics.com
Sent: Thursday, May 02, 2013 7:22 AM
Subject: RE: AeroElectric-List: How to test engine ground?
Dan;
Connect your voltmeter between the battery negative post and the
engine case/starter housing while cranking and see what the voltage drop
is. Very low voltage reading = good ground. significant voltage
reading = bad ground. If you also know what current you're drawing you
can calculate total loop resistance using these readings.
Bob McC
-------------------------------------------------------------------------
-----
Date: Thu, 2 May 2013 09:11:41 -0400
Subject: AeroElectric-List: How to test engine ground?
From: dcheckoway@gmail.com
To: aeroelectric-list@matronics.com
This may seem like a ridiculous question, and hopefully I'll end up
slapping my forehead when I hear the answer...but here goes anyway.
I'd like to quantify, or at least qualify my engine ground connection.
That is, I have a 2 AWG wire connecting my engine to the ground block
on the firewall. Suffice it to say, I have reason to suspect that one
of the connections is less than perfect. I have an intermittent issue
(probably another thread in the making), and I want to rule out ground
as a culprit.
When I throw an ohmmeter across, of course I see zero ohms. But that
only tells me the obvious. It would probably read zero even if I had a
24 AWG wire in its place. :-) And what I'm concerned about is that
maybe it's reading zero despite the engine side connection not making
good enough contact. Probably not, but I'd like to rule it out.
Is there any way (something a doofus like me could do) to test the
quality of this engine ground connection? i.e. when my starter is
sucking 200 amps through that straw, I'd like to know if it's truly
unimpeded so to speak.
Any tips or tricks? Or do we just trust that if the wire is fat
enough, we *think* our connections are fine, the starter cranks and
nothing smokes, then life is good enough?
Thanks,
Dan
-List"
target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
http://forums.matronics.com
="_blank">http://www.matronics.com/contribution
Message 9
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| Subject: | Re: How to test engine ground? |
Oops, replied just before Bob's reply came in...I appreciate the advice
about using the load tester.
Thanks again, and TIA for any replies that come in after this!
On Thu, May 2, 2013 at 11:48 AM, Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> I'd like to quantify, or at least qualify my engine ground connection.
> That is, I have a 2 AWG wire connecting my engine to the ground block on
> the firewall. Suffice it to say, I have reason to suspect that one of the
> connections is less than perfect. I have an intermittent issue (probably
> another thread in the making), and I want to rule out ground as a culprit.
>
> When I throw an ohmmeter across, of course I see zero ohms. But that only
> tells me the obvious. It would probably read zero even if I had a 24 AWG
> wire in its place. :-) And what I'm concerned about is that maybe it's
> reading zero despite the engine side connection not making good enough
> contact. Probably not, but I'd like to rule it out.
>
> *Your observation has roots in the ideas we've discussed in the past . .
> . ideas for quantifying the quality of electrical connections and
> components with very low resistance.
>
> *
> Is there any way (something a doofus like me could do) to test the quality
> of this engine ground connection? i.e. when my starter is sucking 200 amps
> through that straw, I'd like to know if it's truly unimpeded so to speak.
>
> Any tips or tricks? Or do we just trust that if the wire is fat enough,
> we *think* our connections are fine, the starter cranks and nothing smokes,
> then life is good enough?
>
> *One fact that goes favorably to your question is that a really POOR
> joint or component will have a LOT of voltage drop with a commensurate
> concentration of high energy dissipation. For example, a common reason for
> alternators to be returned to B&C for repair is a burned b-lead terminal
> that was so loose as to allow arcing and much heat . . . the terminal
> melted. Some contactor failures present as a valiant effort to maintain
> useful conductivity but with attendant losses in the one volt or more
> range. 1 volt x 200 amps is 200 watts . . . dumping that kind of energy
> into the small area of a degraded contact heats things up rapidly and
> accelerates the failure. See http://tinyurl.com/qmk6gm
>
>
> * Thanks,
> Dan
>
>
> At 09:22 AM 5/2/2013, you wrote:
> Dan;
>
> Connect your voltmeter between the battery negative post and the engine
> case/starter housing while cranking and see what the voltage drop is. Very
> low voltage reading = good ground. significant voltage reading = bad
> ground. If you also know what current you're drawing you can calculate
> total loop resistance using these readings.
>
> Bob McC
>
> *This is a good beginning . . . unfortunately, starters make very poor
> loads for the purpose of conducting diagnostics. Starter current is
> directly related to load . . . which varies wildly as the engine rotates
> through cylinder compression cycles. Taking a reading from a digital
> display watching voltage drops generated by a starter motor is difficult if
> not impossible. An analog meter will be a little better but not by much.
> Measuring voltage drop across various portions of the power loop under
> known load is fundamental to the low-ohms adapter hardware and articles
> offered on the website. The low-ohms adapter illustrated offers a maximum
> of 1 amp excitation current. A bit low for measuring starter circuit drops
> with commonly available instrumentation. One would LIKE to excite a path
> under analysis with a steady 10 or even 100 amps. This isn't as hard as it
> might seem.
>
> **The folks over at Harbor Freight offer this carbon pile load battery
> tester which is capable of developing a reasonably steady state load at 200
> amps or more.
>
> * [image: Emacs!] *To use this device as a circuit quality tester, you
> need to wire it to your airplane such that it REPLACES the starter as a
> load on the system. This is BEST accomplished by adding short test-pigtails
> to the ship's wiring such that the 'test clamps' do not connect to the
> airplane's wiring. If these 'slip' or fail to make good contact throughout
> the test effort, they might arc and damage parts of the airplane. The BEST
> way to make these connections is to cut the clips off the test cables
> leaving about a 6' pigtail on the clip. Install ring terminals that can be
> used to bolt the cable back together later thus restoring the original
> functionality of the tester. With the clips 'unbolted' you can attach
> tester wires to the crankcase and the starter power terminal. For this
> test, remove the jumper on the starter's pinion gear engagement solenoid to
> disable the starter. You might also wish to fabricate a hand held 'pickle
> switch' to energize the ship's starter contactor. The lead wires for this
> piece of equipment needs to be long enough so that you can control the load
> from any place you're observing your voltmeter.
>
> **Now, you may need to enlist the help of someone to 'manage the load' .
> . . tell your assistant to crank the load knob up to achieve the desired
> test current, 100A is probably enough. With a little practice, you can
> easily hold a test current to within 5 amps or so.
>
> **Now, as you probe various portions of the (+) or (-) starter circuit
> with a voltmeter, you can hit the system with a test load likely to produce
> useful readings for voltage drop on your plain-vanilla multimeter . . .
> either digital or analog. Most off-the-shelf meters have a 200 mV full
> scale reading. With voltmeter and pickle-switch in hand, you can explore
> the cranking circuit in its entirety. Any portion of the circuit with
> compromised integrity will probably manifest with rather striking voltage
> drop. Your starter contactor is an intermittent duty device; you want to
> make the readings rather quickly.
>
> **One of the future AEC products being considered is a processor based
> integrator adapter for a digital voltmeter. The device would have two
> inputs: one for voltage drop, the other for battery voltage. A very rapid
> sampling of current (voltage drop) compared with excitation voltage
> (battery terminal voltage) would be evaluated and integrated over time such
> that a technician could analyze system integrity using the engine's starter
> as a load.
> **In the mean time, you can modify the HF battery tester into a
> steady-state load that will yield very useful data for evaluating the
> integrity of your system's fat wire circuits.
>
> **Bob . . . *
>
>
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| Subject: | How to test engine ground? |
I agree with everything said, however.
Before reading anyone else's post my check would have been to check the
voltage at the starter load stud and starter case ground while starting.
If you have a good ground and positive cable your voltage drop will be
minimal. (Sorry I don't know what the baseline for good would be)
You could then take a jumper cable and run from the battery negative and
starter case and do the check again to compare the two.
If the drop is less then the jumper cable made a better ground. If the same
then your ground system works as well.
With a 12.8v battery I would expect somewhere around 10 - 11 volts during
starting. I would assume somewhere less than that could mean that one of the
cables/connections is deficient.
Mark Wesson
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Dan
Checkoway
Sent: Thursday, May 02, 2013 12:00 PM
Subject: Re: AeroElectric-List: How to test engine ground?
Thanks guys, that makes total sense...will give it a shot! (sound of hand
slapping forehead)
Dan
On Thu, May 2, 2013 at 11:27 AM, Jeff Luckey <jluckey@pacbell.net> wrote:
Tim , Bob's use of the term "Voltage Drop" is correct.
--- On Thu, 5/2/13, Tim Andres <tim2542@sbcglobal.net> wrote:
From: Tim Andres <tim2542@sbcglobal.net>
Subject: Re: AeroElectric-List: How to test engine ground?
Dans idea is a good one, but I think he meant misspoke slightly when he said
"voltage drop". You want to know the voltage between the engine case and the
NEG battery terminal while cranking, in other words your volt meter is
placed in parallel with the ground system. Anything more than 1~1-1/2 volts
indicates the ground is not able to drain off the ohm-bugs fast enough and
they are having to wait in line to get home :-). Also if you do have a high
reading (high resistance) you can then go point to point on the different
terminals and find the one causing the problem.
Tim
Sent from my iPad
On May 2, 2013, at 7:22 AM, Bob McCallum <robert.mccallum2@sympatico.ca
<http://mc/compose?to=robert.mccallum2@sympatico.ca> > wrote:
Dan;
Connect your voltmeter between the battery negative post and the engine
case/starter housing while cranking and see what the voltage drop is. Very
low voltage reading = good ground. significant voltage reading = bad ground.
If you also know what current you're drawing you can calculate total loop
resistance using these readings.
Bob McC
_____
Subject: AeroElectric-List: How to test engine ground?
From: dcheckoway@gmail.com <http://mc/compose?to=dcheckoway@gmail.com>
<http://mc/compose?to=aeroelectric-list@matronics.com>
This may seem like a ridiculous question, and hopefully I'll end up slapping
my forehead when I hear the answer...but here goes anyway.
I'd like to quantify, or at least qualify my engine ground connection. That
is, I have a 2 AWG wire connecting my engine to the ground block on the
firewall. Suffice it to say, I have reason to suspect that one of the
connections is less than perfect. I have an intermittent issue (probably
another thread in the making), and I want to rule out ground as a culprit.
When I throw an ohmmeter across, of course I see zero ohms. But that only
tells me the obvious. It would probably read zero even if I had a 24 AWG
wire in its place. :-) And what I'm concerned about is that maybe it's
reading zero despite the engine side connection not making good enough
contact. Probably not, but I'd like to rule it out.
Is there any way (something a doofus like me could do) to test the quality
of this engine ground connection? i.e. when my starter is sucking 200 amps
through that straw, I'd like to know if it's truly unimpeded so to speak.
Any tips or tricks? Or do we just trust that if the wire is fat enough, we
*think* our connections are fine, the starter cranks and nothing smokes,
then life is good enough?
Thanks,
Dan
-List" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
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="_blank">http://www.matronics.com/contribution
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| Subject: | Re: How to test engine ground? |
Your right, and apologies to Bob, I just thought it might be a confusing te
rm, since what he's looking for is a voltage increase from zero.
Tim
Sent from my iPad
On May 2, 2013, at 8:27 AM, Jeff Luckey <jluckey@pacbell.net> wrote:
>
> Tim , Bob's use of the term "Voltage Drop" is correct.
>
>
> --- On Thu, 5/2/13, Tim Andres <tim2542@sbcglobal.net> wrote:
>
> From: Tim Andres <tim2542@sbcglobal.net>
> Subject: Re: AeroElectric-List: How to test engine ground?
> To: "aeroelectric-list@matronics.com" <aeroelectric-list@matronics.com>
> Date: Thursday, May 2, 2013, 8:07 AM
>
> Dans idea is a good one, but I think he meant misspoke slightly when he sa
id "voltage drop". You want to know the voltage between the engine case and t
he NEG battery terminal while cranking, in other words your volt meter is pl
aced in parallel with the ground system. Anything more than 1~1-1/2 volts in
dicates the ground is not able to drain off the ohm-bugs fast enough and the
y are having to wait in line to get home :-). Also if you do have a high rea
ding (high resistance) you can then go point to point on the different term
inals and find the one causing the problem.
> Tim
>
> Sent from my iPad
>
> On May 2, 2013, at 7:22 AM, Bob McCallum <robert.mccallum2@sympatico.ca> w
rote:
>
>> Dan;
>>
>> Connect your voltmeter between the battery negative post and the engine c
ase/starter housing while cranking and see what the voltage drop is. Very lo
w voltage reading = good ground. significant voltage reading = bad groun
d. If you also know what current you're drawing you can calculate total loop
resistance using these readings.
>>
>> Bob McC
>>
>>
>> Date: Thu, 2 May 2013 09:11:41 -0400
>> Subject: AeroElectric-List: How to test engine ground?
>> From: dcheckoway@gmail.com
>> To: aeroelectric-list@matronics.com
>>
>> This may seem like a ridiculous question, and hopefully I'll end up slapp
ing my forehead when I hear the answer...but here goes anyway.
>>
>> I'd like to quantify, or at least qualify my engine ground connection. T
hat is, I have a 2 AWG wire connecting my engine to the ground block on the f
irewall. Suffice it to say, I have reason to suspect that one of the connec
tions is less than perfect. I have an intermittent issue (probably another t
hread in the making), and I want to rule out ground as a culprit.
>>
>> When I throw an ohmmeter across, of course I see zero ohms. But that onl
y tells me the obvious. It would probably read zero even if I had a 24 AWG w
ire in its place. :-) And what I'm concerned about is that maybe it's read
ing zero despite the engine side connection not making good enough contact.
Probably not, but I'd like to rule it out.
>>
>> Is there any way (something a doofus like me could do) to test the qualit
y of this engine ground connection? i.e. when my starter is sucking 200 amp
s through that straw, I'd like to know if it's truly unimpeded so to speak.
>>
>> Any tips or tricks? Or do we just trust that if the wire is fat enough, w
e *think* our connections are fine, the starter cranks and nothing smokes, t
hen life is good enough?
>>
>> Thanks,
>> Dan
>>
>>
>> -List" target="_blank">http://www.matronics.com/Navigator?AeroElectric-
List
>> http://forums.matronics.com
>> ="_blank">http://www.matronics.com/contribution
>>
>>
>>
>> =========================
=========
>> st">http://www.matronics.com/Navigator?AeroElectric-List
>> =========================
=========
>> cs.com
>> =========================
=========
>> matronics.com/contribution
>> =========
>>
>
>
> ank" href="http://www.matronics.com/Navigator?AeroElectric-List">http://
wt; http://www.matronics.com/contrib==============
>
>
>
==========================
=========
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| Subject: | Call for cover photos . . . |
The AeroElectric Connection is being updated for
Revision 13. This will be a complete re-write/re-formatting
activity for all chapters.
The cover of R12 was graced with a picture of an
exemplary demonstration of the OBAM aviation
arts. I'm looking for a cover photo for R13.
Just like last time, AeroElectric List members
will pick the winner. I'm accepting nominations
to publish on the website. I'm thinking we'll do
a two-stage run-off to (1) select the top five choices
from the field and (2) select the winner from the
top five.
In case of a tie, Dr. Dee will be the tie-breaker.
The ball is in your court folks . . .
Bob . . .
Message 13
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| Subject: | Re: Radio interference |
At 07:25 AM 5/2/2013, you wrote:
><robintaylor@airteccc.co.uk>
>
>Thanks for the response Bob,
>I had to wait until I flew again.
>I am flying with twin Dynon Skyviews, as I turn each off, the noise
>progressively reduces.
>The frequency of the noise increases with the speed of the engine.
>I have a common ground on the firewall that everything is connected to.
Hmmmm . . . Do the Dynon units have audio outputs
for annunciation/warning signals?
Bob . . .
Message 14
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| Subject: | Re: Radio interference |
Yes, the Dynons do have an audio output.
Thanks,
Robin
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=399896#399896
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