Today's Message Index:
----------------------
1. 06:48 AM - Re: GTR-200 garbeled reception (eschlanser)
2. 12:53 PM - Re: an Alternator Load Dump...?... (Robert L. Nuckolls, III)
3. 01:07 PM - Re: strobe noise (Finn Lassen)
4. 05:30 PM - Re: an Alternator Load Dump...?... (Robert L. Nuckolls, III)
5. 05:59 PM - Re: an Alternator Load Dump...?... (Fred Klein)
6. 06:40 PM - Re: an Alternator Load Dump...?... (user9253)
7. 08:26 PM - Re: an Alternator Load Dump...?... (Robert L. Nuckolls, III)
Message 1
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| Subject: | Re: GTR-200 garbeled reception |
Marty,
Have you tried it in another aircraft that has a GTR-200 that is working? I had
a similar problem with my GNS-430W. I dont know how similar these two radios
connectors are, but I verified my radio was ok by testing it in another airplane.
Then I started troubleshooting my installation. I thought I had it seated
ok, but it only takes but a tiny, tiny bit to be not seated well. At least in
mine anyway.
Check out the radio first, and go from there. Good luck.
Not an A&P,
Eric
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498878#498878
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| Subject: | Re: an Alternator Load Dump...?... |
At 10:18 PM 10/16/2020, you wrote:
>Gentlemen,
>
>In a Europa XS mono, I=99ve a RAM Performance
>engine based upon the Subaru EA-81; it has a
>one-wire, 14 volt, 55 amp. Super Mini Denso
>Racing Alternator with external load dump feature.
>Under =9CDetails=9D on the
>=9C<http://gzmotorsports.com>gzmotorsports.com=9D
> webpage for this alternator is the following:
>>
>>What is a Alternator Load Dump?
>>
>>When an alternator is in operation and
>>generating current, if the load is suddenly
>>disconnected (for example your main kill switch
>>activated disconnecting the battery from the
>>alternator) the alternator voltage can spike to
>>as high as 120 volts DC and last for as long as
>>400ms. Voltage spikes that high can damage
>>sensitive electronics like MSD Boxes, Data
>>Loggers, Delay Boxes and other racing
>>equipment. Alternators with a load dump feature
>>are designed to shunt that high voltage to
>>ground if the load is suddenly disconnected, protecting your electronics.
See attached image captured from that site
>Q1: Is this just another name for over voltage
>protection which is built in or attached to an alternator?
>Q2: Will the use of this alternator with LiFePO4
>batteries pose any special issues.
>
>(I am in the process of swapping out 2 Odyssey
>PC680 batteries for EarthX ETX680 batteries;
>with regarding to battery charging, I do know
>that with the Lithium batteries I will need a
>charger which does not charge above 14.6V., will
>automatically turns off when the battery is
>fully charged (based on volts), and does not
>have a de-sulfate mode/deep conditioning mode/pulse mode.)
>
>I have followed Bob=99s Z-19 wiring schematic
>for single alternator w/ two batteries.
This is a smoke/mirrors description of what
I'll bet is a commercial-off-the shelf
alternator you can buy at AutoZone, et. als.
First, the term 'racing' applied to these machines
is mis-leading. First, who needs 55 or 100+ amps
of alternator to run their stock car or dirt track
racer? And 'dead battery' worries . . . really?
My son was into dirt-track entertainment about
20 years ago . . . some of those guys would
start their cars with a jump-battery and run
alternator only just to get 20+ pounds off
the front end of the car.
I seriously doubt that anything extra-ordinary
is done to those alternators to make them
more suited to 'racing' as opposed to service
in earth moving machines or family chariots.
That 'load dump' thing is another monster-
sleeping-under-the-bed meme. The promotion
admits that to experience that bunch-o-volts
excursion of bus voltage, you gotta have
simultaneous battery disconnect AND a
heavily battery-loaded alternator
(i.e. carrying LIGHT system loads plus recharging a
heavily discharged battery). How often
does that happen? We wire our airplanes
such that alternators are turned ON LAST
and OFF FIRST. Same thing with 99.9% of
all TC S.E. aircraft.
But what about that 'load dump protection
feature'? See that little red gizmo attached
to the alternator b-lead terminal? That's
a metal oxide varistor. It's a technology
widely used for LOW ENERGY transient
suppression for sources with rather high
source impedance. These things are used
by the tens of millions in all manner
of consumer products to help stand off
indirect effects of lighting strike to
power lines and inductively driven transients
in consumer electronics and vehicles. Those
'surge protected' plug strips hanging
on pegs at Walmart? They've got a couple
MOVs in 'em.
Remember the triad of competent engineering?
Properties of materials, energy management
and refinement of process. Let's go look
at an exemplar, low voltage MOV that just
might seem attractive to a starry-eyed
alternator entrepreneur:
In the attached photo we see the MOV
'load dump' protector. I would judge it
to be no bigger than 20mm diameter. Referring
to the attached catalog excerpt, a 20P17A
MOV from Littlefuse can stand of ONE, 35
Joule (watt second) pulse for 2 MILLISECONDS.
So peak power is 35/0.002 or 17,500 Watts . . .
okay for a little tickle from that lightning
stroke down the street but it better not
last long.
Okay, the advert for this alternator speaks
to outputs of up to 100V for 400 MILLISECONDS.
Hmmm . . . energy management time.
Assume the MOV strives to clamp off the 55A
rated alternator at about 40 volts (2200
watts). How long would this 35 watt-second
device last while trying to grunt 2200 watts?
You deduced it . . . not long.
Some of you graybeards may recall a fellow
back about 1990 that was offering a similar
'over voltage protection' on his alternators
in the form of a molded plastic, 1 Watt
zener tied from b-lead to case ground.
A reader of these pages posted an event
report wherein he discovered that his ov
protection was AWOL . . . it just disappeared.
Two wires were left dangling from the terminals
but the entire diode had vanished.
His project had experienced a transient
event that caused the po' little zener
to grunt several magnitudes more energy
than it was designed for . . . POOF!
On a different but related matter, the
alternator under discussion is offered as
a 1-Wire device. These products are designed
for the automotive world. Hook the b-lead
to the battery. Electronics in the regulator
sees the rotor is not turning . . . field
supply is shut off.
Start engine, rotor spins, field excitation
comes alive and KilloJoules of energy become
available for all manner of good things.
But you do not have positive, external
control of these alternators. Smoke in the
cockpit . . . tough toenail . . . can't
shut the alternator off without stopping
the engine. Perhaps no big deal in your
ground-bound machine . . . not so much
at 8,500 feet and 10+ minutes away from
wheels-on-the-ground.
If your desire is to exploit the great
bargains in COTS alternators, get one from
your local Smiley Jack's Autoparts Emporium
and plan on modifying for external regulation
and ABSOLUTE CREW CONTROL OF the machine's
output which INCLUDES AUTOMATIC OV PROTECTION.
Not hard to do . . . and by the way ignore
that load dump floobydust . . .
Bob . . .
Message 3
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| Subject: | Re: strobe noise |
Try to trace the path from the alternator case to the negative terminal
of the battery.
Ground strap between engine and airframe?
As Bob pointed out, that old airframe may not provide a good ground
path. If possible, temporarily for testing, a good size wire from
alternator to battery negative terminal.
Perhaps another way of looking at it: is the ground path to the radio in
any way carrying a current between alternator and battery ground?
Finn
On 10/17/2020 12:47 AM, Bernie wrote:
> Just thought of some others things to try to isolate the noise source.
> With all the avionics on each one was turned off and on one at a time.
> No noise change
> Changed phone plug from intercom Jack to aux jack thats wired direct
> to the com through the audio panel, noise remains
> Audio panel off, no change noise remains
> Changed volume on ADF, KX155, intercom, no change in the Volume of LED
> based cyclic noise
>
> The only way to eliminate the noise is to disable the alternator.
>
> I can Check the integrity of the connection to the buss and the
> alternator B. What else should be checked?
>
> Bernie
>
> Sent from my iPhone
>
>> On Oct 16, 2020, at 7:32 PM, Bernie <arcticarrow@gmail.com> wrote:
>>
>> Hello Guys
>> Made some progress trouble shooting the LED strobe and wig wag noise.
>> Grounded the regulator per the plan power installation directions
>> with 16 ga. Wire to the firewall battery ground. Also cleaned all the
>> ground lugs at this point.
>>
>> Ran the engine and have the same noise except when the alternator
>> field is tripped shutting down the alternator.
>>
>> Next step will be to confirm the B lead is tight on both ends. Any
>> other suggestions?
>>
>> Thanks Bernie
>>
>> Sent from my iPhone
>>
>>> On Oct 14, 2020, at 12:31 PM, Robert L. Nuckolls, III
>>> <nuckolls.bob@aeroelectric.com> wrote:
>>>
>>> At 10:33 AM 10/14/2020, you wrote:
>>>> Thanks to all of you for the quick responses. Ill be back to the
>>>> airplane in a couple days.
>>>>
>>>> It is a 1956 G Bonanza.
>>>
>>> Hmmm . . . airplanes of this vintage are
>>> renowned for high resistance airframes which
>>> are fertilizer for ground loop issues.
>>>
>>>> Plane power alternator. The strobes and wig wag noise is an
>>>> alternating ping/hum. The
>>>> pitot heat and landing lights are a steady hum. The LED beacon is
>>>> quiet.
>>>
>>>
>>> Are all the 'hums' the same pitch and do they
>>> rise and fall with alternator rpm?
>>>
>>>> I did found an empty grounding lug on the regulator. All of the
>>>> above elec. devices are grounded
>>>> to a ground buss which is stainless bolted to a bulkhead.
>>>
>>> . . . all this happens behind the cabin?
>>>
>>>> Older radios are grounded to various unknown places.
>>>> The noise goes away when I shut down the engine but haven't tried
>>>> Turing off the alternator with
>>>> the engine running.
>>>
>>> This is key . . . but I'm betting the noise
>>> is unique to the alternator and will go
>>> away with the alternator off. Where is
>>> the battery in this airplane?
>>>
>>>
>>>> In the mean time would a 16 gauge wire be appropriate to ground the
>>>> alternator?
>>>
>>> alternator? above you cited the regulator? If it's
>>> the regulator then don't worry about it. A regulator
>>> ground is never root cause of the constellation of
>>> symptoms you've listed.
>>>
>>> Bob . . .
>>>
---
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Message 4
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| Subject: | Re: an Alternator Load Dump...?... |
At 10:18 PM 10/16/2020, you wrote:
>Gentlemen,
>
>In a Europa XS mono, I=99ve a RAM Performance
>engine based upon the Subaru EA-81; it has a
>one-wire, 14 volt, 55 amp. Super Mini Denso
>Racing Alternator with external load dump feature.
>Under =9CDetails=9D on the
>=9C<http://gzmotorsports.com>gzmotorsports.com=9D
> webpage for this alternator is the following:
>>
>>What is a Alternator Load Dump?
>>
>>When an alternator is in operation and
>>generating current, if the load is suddenly
>>disconnected (for example your main kill switch
>>activated disconnecting the battery from the
>>alternator) the alternator voltage can spike to
>>as high as 120 volts DC and last for as long as
>>400ms. Voltage spikes that high can damage
>>sensitive electronics like MSD Boxes, Data
>>Loggers, Delay Boxes and other racing
>>equipment. Alternators with a load dump feature
>>are designed to shunt that high voltage to
>>ground if the load is suddenly disconnected, protecting your electronics.
See attached image captured from that site
>Q1: Is this just another name for over voltage
>protection which is built in or attached to an alternator?
>Q2: Will the use of this alternator with LiFePO4
>batteries pose any special issues.
>
>(I am in the process of swapping out 2 Odyssey
>PC680 batteries for EarthX ETX680 batteries;
>with regarding to battery charging, I do know
>that with the Lithium batteries I will need a
>charger which does not charge above 14.6V., will
>automatically turns off when the battery is
>fully charged (based on volts), and does not
>have a de-sulfate mode/deep conditioning mode/pulse mode.)
>
>I have followed Bob=99s Z-19 wiring schematic
>for single alternator w/ two batteries.
This is a smoke/mirrors description of what
I'll bet is a commercial-off-the shelf
alternator you can buy at AutoZone, et. als.
First, the term 'racing' applied to these machines
is mis-leading. First, who needs 55 or 100+ amps
of alternator to run their stock car or dirt track
racer? And 'dead battery' worries . . . really?
My son was into dirt-track entertainment about
20 years ago . . . some of those guys would
start their cars with a jump-battery and run
alternator only just to get 20+ pounds off
the front end of the car.
I seriously doubt that anything extra-ordinary
is done to those alternators to make them
more suited to 'racing' as opposed to service
in earth moving machines or family chariots.
That 'load dump' thing is another monster-
sleeping-under-the-bed meme. The promotion
admits that to experience that bunch-o-volts
excursion of bus voltage, you gotta have
simultaneous battery disconnect AND a
heavily battery-loaded alternator
(i.e. carrying LIGHT system loads plus recharging a
heavily discharged battery). How often
does that happen? We wire our airplanes
such that alternators are turned ON LAST
and OFF FIRST. Same thing with 99.9% of
all TC S.E. aircraft.
But what about that 'load dump protection
feature'? See that little red gizmo attached
to the alternator b-lead terminal? That's
a metal oxide varistor. It's a technology
widely used for LOW ENERGY transient
suppression for sources with rather high
source impedance. These things are used
by the tens of millions in all manner
of consumer products to help stand off
indirect effects of lighting strike to
power lines and inductively driven transients
in consumer electronics and vehicles. Those
'surge protected' plug strips hanging
on pegs at Walmart? They've got a couple
MOVs in 'em.
Remember the triad of competent engineering?
Properties of materials, energy management
and refinement of process. Let's go look
at an exemplar, low voltage MOV that just
might seem attractive to a starry-eyed
alternator entrepreneur:
In the attached photo we see the MOV
'load dump' protector. I would judge it
to be no bigger than 20mm diameter. Referring
to the attached catalog excerpt, a 20P17A
MOV from Littlefuse can stand of ONE, 35
Joule (watt second) pulse for 2 MILLISECONDS.
So peak power is 35/0.002 or 17,500 Watts . . .
okay for a little tickle from that lightning
stroke down the street but it better not
last long.
Okay, the advert for this alternator speaks
to outputs of up to 100V for 400 MILLISECONDS.
Hmmm . . . energy management time.
Assume the MOV strives to clamp off the 55A
rated alternator at about 40 volts (2200
watts). How long would this 35 watt-second
device last while trying to grunt 2200 watts?
You deduced it . . . not long.
Some of you graybeards may recall a fellow
back about 1990 that was offering a similar
'over voltage protection' on his alternators
in the form of a molded plastic, 1 Watt
zener tied from b-lead to case ground.
A reader of these pages posted an event
report wherein he discovered that his ov
protection was AWOL . . . it just disappeared.
Two wires were left dangling from the terminals
but the entire diode had vanished.
His project had experienced a transient
event that caused the po' little zener
to grunt several magnitudes more energy
than it was designed for . . . POOF!
On a different but related matter, the
alternator under discussion is offered as
a 1-Wire device. These products are designed
for the automotive world. Hook the b-lead
to the battery. Electronics in the regulator
sees the rotor is not turning . . . field
supply is shut off.
Start engine, rotor spins, field excitation
comes alive and KilloJoules of energy become
available for all manner of good things.
But you do not have positive, external
control of these alternators. Smoke in the
cockpit . . . tough toenail . . . can't
shut the alternator off without stopping
the engine. Perhaps no big deal in your
ground-bound machine . . . not so much
at 8,500 feet and 10+ minutes away from
wheels-on-the-ground.
If your desire is to exploit the great
bargains in COTS alternators, get one from
your local Smiley Jack's Autoparts Emporium
and plan on modifying for external regulation
and ABSOLUTE CREW CONTROL OF the machine's
output which INCLUDES AUTOMATIC OV PROTECTION.
Not hard to do . . . and by the way ignore
that load dump floobydust . . .
Bob . . .
Bob . . .
Message 5
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| Subject: | Re: an Alternator Load Dump...?... |
Bobthank you for addressing my questions; you wrote:
> On Oct 17, 2020, at 5:28 PM, Robert L. Nuckolls, III
<nuckolls.bob@aeroelectric.com> wrote:
>
> If your desire is to exploit the great
> bargains in COTS alternators, get one from
> your local Smiley Jack's Autoparts Emporium
> and plan on modifying for external regulation
> and ABSOLUTE CREW CONTROL OF the machine's
> output which INCLUDES AUTOMATIC OV PROTECTION.
As I think I mentioned, my engine came with the 55 amp. Denso
alternatorhaving it is not the result of my seeking great
bargains in COTS alternators. I do recall reading on the topic of OV
protection (without really understanding), and the topic has come up
because of what I=99m learning about LiFePO4 batteries and their
sensitivity to voltage spikes. So thank you for bringing the issue front
and center.
I trust that consuting my AeroElectric Connection will reveal just how
this alternator can be modified =9Cfor external regulation and
absolute crew control of the machine=99s output which includes
automatic OV protection.
Fred
Message 6
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| Subject: | Re: an Alternator Load Dump...?... |
Here is a link to converting an alternator to external voltage regulation:
http://www.aeroelectric.com/articles/Alternators/One-Wire_Alternator_Conversion.pdf
Here is a link to a Kitplanes article about converting an alternator:
https://www.kitplanes.com/rewiring-a-nippondenso-alternator/
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498883#498883
Message 7
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| Subject: | Re: an Alternator Load Dump...?... |
>As I think I mentioned, my engine came with the
>55 amp. Denso alternator=85having it is not the
>result of my seeking great bargains in COTS
>alternators. I do recall reading on the topic of
>OV protection (without really understanding),
>and the topic has come up because of what I=99m
>learning about LiFePO4 batteries and their
>sensitivity to voltage spikes. So thank you for
>bringing the issue front and center.
Good show. LiFePO4 batteries with battery management
systems are no more 'sensitive to spikes' than any
SLVA battery. That's what the BMS is for. Also,
the term 'spike' is never defined in terms of amplitude,
duration, waveshape and/or source impedance.
The DC supply of ALL vehicles is rife with NOISE of
various characterizations. 99.9% of people who
look at plots of those noises are inclined to
say, "Hey Martha . . . lookit all those spikes".
Keep in mind that people who are competing in the
lithium cranking battery market are striving to
make their product just as plug-n-play as they
can for replacing SLVA. When assessing suitability
of a marriage between your airplane and any
LiFePO4 product . . . check the engineering system
integration data sheet where limits are spelled
out in measurable physical quantities. The term
'spike' is not measurable and should be ignored
unless accompanied with detailed explanation.
I've not found any reason to be concerned about
dropping LiFePO4 products into a legacy SVLA
slot and adjusting the regulator for 14.2 volts.
>I trust that consuting my AeroElectric
>Connection will reveal just how this alternator
>can be modified =9Cfor external regulation and
>absolute crew control of the machine=99s output
>which includes automatic OV protection.
No, too many variables to cover in that
document but as Joe cited, here are some
excellent resources on the 'net. Keep
us apprised of your progress and potholes.
Bob . . .
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