Today's Message Index:
----------------------
1. 02:48 AM - Re: Odyssey Battery Longevity (Henador Titzoff)
2. 05:22 AM - Re: Odyssey Battery Longevity (Ron Burnett)
3. 06:06 AM - Re: Odyssey Battery Longevity (BobsV35B@aol.com)
4. 08:14 AM - Re: Odyssey Battery Longevity (Robert L. Nuckolls, III)
5. 08:27 AM - Re: Odyssey Battery Longevity (Robert L. Nuckolls, III)
6. 08:32 AM - Re: B&C alternator diagnosis (Robert L. Nuckolls, III)
7. 08:41 AM - Re: Preventing RF Noise Pollution (Jeff Luckey)
8. 08:43 AM - Re: Odyssey Battery Longevity (Robert L. Nuckolls, III)
9. 11:03 AM - Re: B&C alternator diagnosis (user9253)
10. 11:14 AM - More than you ever wanted to know about Li-on batteries (John Loram)
11. 12:06 PM - Re: More than you ever wanted to know about Li-on batteries (John Loram)
12. 01:11 PM - Re: Re: B&C alternator diagnosis (Robert L. Nuckolls, III)
13. 01:12 PM - single vs. 3-phase alternators (forgot the picture!) (Robert L. Nuckolls, III)
14. 02:40 PM - Re: single vs. 3-phase alternators (forgot the picture!) (James Robinson)
15. 02:50 PM - Re: single vs. 3-phase alternators (forgot the picture!) (Neal George)
16. 02:52 PM - Re: vhf transponder interference (jappie)
Message 1
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| Subject: | Re: Odyssey Battery Longevity |
Great story, Dean! -Looks like your PC680 is cost effective.
I have Odysseys in my airplane and all of my automobiles (6). -This "expe
riment started about 3.5 years ago, and I had one poop out at 3 years exact
ly. The rest are still cranking engines and tunes.
As part of your longevity experiment, why not take it out after 2, 3, 4 ...
years and have its capacity tested? -An interesting observation about my
Odyssey failure was that it wasn't catastrophic; instead, it declined stea
dily. At first I thought it was the fuel system causing delayed starting, b
ut I had its capacity tested and found it at 70% capacity. Replacement solv
ed all problems.
Henador Titzoff
--- On Tue, 10/30/12, DEAN PSIROPOULOS <dean.psiropoulos@verizon.net> wrote
:
From: DEAN PSIROPOULOS <dean.psiropoulos@verizon.net>
Subject: AeroElectric-List: Odyssey Battery Longevity
os@verizon.net>
Just finished my fourth annual on the RV-6A.- When I built the airplane I
installed the firewall mounted battery kit with the Odyssey PC680 battery.
Being an aficionado of Bob's philosophy I was originally going to replace
the battery after two years of service.- I had however, heard many great
things about the Odyssey and decided to keep it in service after my second
annual, it was working perfectly and I could find no reason to spend anothe
r
$150 for a new one.- Same great service in 2011 so I decided I'd let it r
un
for one more year.- This year I decided I'd replace it regardless of how
it
was performing so, I bought a new- one and installed it (even though the
4
year old one still cranked the airplane vigorously).- I was curious how m
uch
capacity remained in the old battery so I took it to an auto parts store an
d
had them load test it.- Results...4 year old Odyssey still put out 207 of
its 220 CCA rated capacity.- That's an incredible 94% capacity remaining
after FOUR years!!! Down here in Florida we are lucky to get 4 years of
service out of a flooded cell car battery and the Odyssey still gives a
whopping 94% of the capacity it had when I bought it!- Awesome battery, I
think I let the new one go 5-6 years and see how it performs.-
Dean Psiropoulos
RV-6A N197DM
Going on 5 fun filled years
le, List Admin.
Message 2
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| Subject: | Re: Odyssey Battery Longevity |
Go to Wholesale Battery for best prices on Odessey, at least here in MO.
Ron Burnett N524RB Subaru powered RV-6A
Sent from my iPad
May you have the blessings of the Lord today.
On Oct 31, 2012, at 4:47 AM, Henador Titzoff <henador_titzoff@yahoo.com> wro
te:
>
> Great story, Dean! Looks like your PC680 is cost effective.
>
> I have Odysseys in my airplane and all of my automobiles (6). This "exper
iment started about 3.5 years ago, and I had one poop out at 3 years exactly
. The rest are still cranking engines and tunes.
>
> As part of your longevity experiment, why not take it out after 2, 3, 4 ..
. years and have its capacity tested? An interesting observation about my O
dyssey failure was that it wasn't catastrophic; instead, it declined steadil
y. At first I thought it was the fuel system causing delayed starting, but I
had its capacity tested and found it at 70% capacity. Replacement solved al
l problems.
>
> Henador Titzoff
>
> --- On Tue, 10/30/12, DEAN PSIROPOULOS <dean.psiropoulos@verizon.net> wrot
e:
>
> From: DEAN PSIROPOULOS <dean.psiropoulos@verizon.net>
> Subject: AeroElectric-List: Odyssey Battery Longevity
> To: aeroelectric-list@matronics.com
> Date: Tuesday, October 30, 2012, 7:42 PM
>
los@verizon.net>
>
> Just finished my fourth annual on the RV-6A. When I built the airplane I
> installed the firewall mounted battery kit with the Odyssey PC680 battery.
> Being an aficionado of Bob's philosophy I was originally going to replace
> the battery after two years of service. I had however, heard many great
> things about the Odyssey and decided to keep it in service after my second
> annual, it was working perfectly and I could find no reason to spend anoth
er
> $150 for a new one. Same great service in 2011 so I decided I'd let it ru
n
> for one more year. This year I decided I'd replace it regardless of how i
t
> was performing so, I bought a new one and installed it (even though the 4
> year old one still cranked the airplane vigorously). I was curious how mu
ch
> capacity remained in the old battery so I took it to an auto parts store a
nd
> had them load test it. Results...4 year old Odyssey still put out 207 of
> its 220 CCA rated capacity. That's an incredible 94% capacity remaining
> after FOUR years!!! Down here in Florida we are lucky to get 4 years of
> service out of a flooded cell car battery and the Odyssey still gives a
> whopping 94% of the capacity it had when I bought it! Awesome battery, I
> think I let the new one go 5-6 years and see how it performs.
>
> Dean Psiropoulos
> RV-6A N197DM
> Going on 5 fun filled ?AeroElectric-List" target="_blank">http://www.mat
ronics.com/Navigator?Ae - MATRONICS WEBcom" bsp;
-Matt Dralle, List Adontribution" target="_blank">http://www.matronics.co
m/contribution
>
>
>
>
==========================
=========
==========================
=========
==========================
=========
==========================
=========
>
Message 3
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| Subject: | Re: Odyssey Battery Longevity |
Good Morning Dean and Henador,
I wonder what type of capacity check was performed by the facility Dean
used?
When I asked my automobile service facility to run a capacity check, they
told me they could do it in less than five minutes. According to the
directions on my capacity checker, it takes several hours! First, the battery
must be checked to assure it is fully charged, then it needs to be
discharged at an accurately controlled rate as specified by the manufacturer.
Was
that protocol followed by the automotive testing facility?
I too have had good luck with a couple of Odyssey batteries I bought, but I
do not have any confidence at all in a capacity check such as used at the
local battery shop.
Just wonderin'?
Happy Skies,
Old Bob
In a message dated 10/31/2012 4:49:52 A.M. Central Daylight Time,
henador_titzoff@yahoo.com writes:
Great story, Dean! Looks like your PC680 is cost effective.
I have Odysseys in my airplane and all of my automobiles (6). This
"experiment started about 3.5 years ago, and I had one poop out at 3 years
exactly. The rest are still cranking engines and tunes.
As part of your longevity experiment, why not take it out after 2, 3, 4
... years and have its capacity tested? An interesting observation about my
Odyssey failure was that it wasn't catastrophic; instead, it declined
steadily. At first I thought it was the fuel system causing delayed starting,
but I had its capacity tested and found it at 70% capacity. Replacement
solved all problems.
Henador Titzoff
--- On Tue, 10/30/12, DEAN PSIROPOULOS <dean.psiropoulos@verizon.net>
wrote:
From: DEAN PSIROPOULOS <dean.psiropoulos@verizon.net>
Subject: AeroElectric-List: Odyssey Battery Longevity
<_dean.psiropoulos@verizon.net_
(mip://121999c0/mc/compose?to=dean.psiropoulos@verizon.net) >
Just finished my fourth annual on the RV-6A. When I built the airplane I
installed the firewall mounted battery kit with the Odyssey PC680 battery.
Being an aficionado of Bob's philosophy I was originally going to replace
the battery after two years of service. I had however, heard many great
things about the Odyssey and decided to keep it in service after my second
annual, it was working perfectly and I could find no reason to spend
another
$150 for a new one. Same great service in 2011 so I decided I'd let it run
for one more year. This year I decided I'd replace it regardless of how it
was performing so, I bought a new one and installed it (even though the 4
year old one still cranked the airplane vigorously). I was curious how
much
capacity remained in the old battery so I took it to an auto parts store
and
had them load test it. Results...4 year old Odyssey still put out 207 of
its 220 CCA rated capacity. That's an incredible 94% capacity remaining
after FOUR years!!! Down here in Florida we are lucky to get 4 years of
service out of a flooded cell car battery and the Odyssey still gives a
whopping 94% of the capacity it had when I bought it! Awesome battery, I
think I let the new one go 5-6 years and see how it performs.
Dean Psiropoulos
RV-6A N197DM
Going on 5 fun filled ?AeroElectric-List"
target="_blank">http://www.matronics.com/Navigator?Ae - MATRONICS WEBcom" bsp; -Matt Dralle, List
Adontribution" target="_blank">http://www.matronics.com/contribution
Message 4
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| Subject: | Re: Odyssey Battery Longevity |
At 04:47 AM 10/31/2012, you wrote:
>Great story, Dean! Looks like your PC680 is cost effective.
>
>I have Odysseys in my airplane and all of my automobiles (6). This
>"experiment started about 3.5 years ago, and I had one poop out at 3
>years exactly. The rest are still cranking engines and tunes.
>
>As part of your longevity experiment, why not take it out after 2,
>3, 4 ... years and have its capacity tested? An interesting
>observation about my Odyssey failure was that it wasn't
>catastrophic; instead, it declined steadily. At first I thought it
>was the fuel system causing delayed starting, but I had its capacity
>tested and found it at 70% capacity. Replacement solved all problems.
>Henador Titzoff
YES! You got a gold star!
Bob . . .
Message 5
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| Subject: | Re: Odyssey Battery Longevity |
At 08:05 AM 10/31/2012, you wrote:
Good Morning Dean and Henador,
I wonder what type of capacity check was performed by the facility Dean used?
When I asked my automobile service facility to run a capacity check,
they told me they could do it in less than five minutes. According
to the directions on my capacity checker, it takes several
hours! First, the battery must be checked to assure it is fully
charged, then it needs to be discharged at an accurately controlled
rate as specified by the manufacturer. Was that protocol followed by
the automotive testing facility?
I too have had good luck with a couple of Odyssey batteries I bought,
but I do not have any confidence at all in a capacity check such as
used at the local battery shop.
Just wonderin'?
A worthy question sir . . .
Bob . . .
Message 6
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| Subject: | B&C alternator diagnosis |
At 07:14 PM 10/30/2012, you wrote:
>Bob,
>This is fairly common in the RC industry.
>See <http://mysite.verizon.net/vze49gsg>http://mysite.verizon.net/vze49gsg
>Raja may be interested in building the rectifiers.
>
Yeah, those little RC BLDC motors are amazing products.
I've got a couple here that have been played with a bit.
A few years ago, I was asked to proposed a table-top
demonstrator for quantifying both brushed and
brushless DC motor performance. Never got a response
back on my proposal. But it was an opportunity to
sample what was out there.
I've considered studying their application in a wind-driven
power source for ultra-lights and antiques. But that's
a project WAAAAaaayyy back on the burners!
Bob . . .
Message 7
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| Subject: | Preventing RF Noise Pollution |
Bob,
Thanks for the pointers. When I get closer to PCB fabrication, I may take
you up on your generous offer.
-Jeff
-----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, October 30, 2012 13:35
Subject: Re: AeroElectric-List: Preventing RF Noise Pollution
<nuckolls.bob@aeroelectric.com>
At 01:36 PM 10/30/2012, you wrote:
All,
I want to put a device which contains a micro-controller clocked @ 1 MHz in
my RV-7. I want it to be a good electronic citizen in the electromagnetic
village of my electrical system. (I don't want it to annoy its neighbors)
I'm looking for guidelines on how to prevent the device from introducing
noise back thru its power feed line. Can I put a filter on the circuit
board on the incoming power line? There is a 5v regulator - are those
devices noisy?
In an effort to reduce radiated noise, it is enclosed in an aluminum box
that seals well.
#1 rule, make the board layout tight. Make use of a
ground plane if you can. Self contained uC devices
have VERY tiny radiation apertures and few external
leads (oscillator) that carry fast rise, potentially
antagonistic signals.
There is also control wiring that must travel thru the airframe. Should
those wires have some kind of filtering on them as well? Some of the
external wires are sensing remote analog voltages. Do they need protection
also?
Generally not for RF. Your control and analog lines will
generally benefit from some form of level shifting and/or
filtering for input transient immunity . . . this same
network wipes out the RF issues too.
Power inputs for small circuits are also benign. You'll
no doubt be using a linear regulator which, along with
it's standard line capacitors, is a strong attenuator
of RF.
Small devices like this are seldom an radiated
or conducted EMI concern. Your biggest integration
concerns are for protecing the uC from outside
stresses (Mil-Std-704 DC power and static discharges
for handling).
Send me a copy of your schematic and I'll suggest
i/o conditioning networks.
Bob . . .
-----
No virus found in this message.
Checked by AVG - www.avg.com
Message 8
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| Subject: | Re: Odyssey Battery Longevity |
At 09:42 PM 10/30/2012, you wrote:
><dean.psiropoulos@verizon.net>
>
>Just finished my fourth annual on the RV-6A. When I built the airplane I
>installed the firewall mounted battery kit with the Odyssey PC680 battery.
>Being an aficionado of Bob's philosophy I was originally going to replace
>the battery after two years of service.
Allow me to clarify the 'philosophy'. A design goal for
battery management is to maintain a high level of CONFIDENCE
in the battery's ability to perform intended tasks of
(1) getting the engine started and more important (2)
support alternator-out operations to some bench-mark
established by the builder/pilot. That bench mark MAY
be the legacy 30-minutes duration embraced by the TC
aircraft world or duration0-of-fuel-aboard encouraged
by this author.
That standard is achieved by either periodic testing of
battery capacity under loads similar to those expected in
the airplane . . . or simple change out at intervals pretty
much guaranteed to maintain system integrity for battery-only
ops.
This is a judgement call. Cost of ownership must include
the labor and equipment necessary for periodic testing.
A $150 battery rotated out of the airplane costs $75/year.
If 30 minute expenditures of test time, say 4x times over
the next two years forestalls a change-out, then battery
costs are now $37/year + two hours + depreciation of
test equipment.
If the airplane is fitted with two alternators, then
rational design goals might call for leaving a battery
in place until it no longer cranks the engine. I.e. it's
never expected to perform as a standby source of energy.
It's up to the builder to decide where the economics of
a particular philosophy drive the decision to replace
the battery.
> I had however, heard many great
>things about the Odyssey and decided to keep it in service after my second
>annual, it was working perfectly and I could find no reason to spend another
>$150 for a new one.
On what basis did you assess perfection? What are
the design goals for this battery's utilization
in your airplane?
> Same great service in 2011 so I decided I'd let it run
>for one more year. This year I decided I'd replace it regardless of how it
>was performing so, I bought a new one and installed it (even though the 4
>year old one still cranked the airplane vigorously).
. . . a prima facie demonstration of performance under
cranking loads.
>I was curious how much
>capacity remained in the old battery so I took it to an auto parts store and
>had them load test it.
A load test is not a capacity test. Automotive batteries
are only expected to crank engines. Gross capacity is seldom
an automotive issue and is never tested. Now, if the battery
is used in an RV to run lights and refrigerators, that becomes
a capacity issue for battery that is expected to perform under
deep cycle service.
> Results...4 year old Odyssey still put out 207 of
>its 220 CCA rated capacity. That's an incredible 94% capacity remaining
>after FOUR years!!! Down here in Florida we are lucky to get 4 years of
>service out of a flooded cell car battery and the Odyssey still gives a
>whopping 94% of the capacity it had when I bought it! Awesome battery, I
>think I let the new one go 5-6 years and see how it performs.
I have instrumentation batteries that are over 10 years
old and still test at better than 75% of new CAPACITY.
They load test well too . . . well over 200 amps for 15 seconds
at or above 9 volts. They have been well cared for, seldom
deep cycled, and could be dropped into one of my vehicles
for a last gasp at utilitarian service.
I'm not surprised at your experience in that climate. I
suspect as a devotee of the AeroElectric-List, your situational
awareness of electrical system performance is well above
that of the majority of GA pilots. Folks who understand,
observe and react to slips in system performance will enjoy
exemplary service from their electro-whizzies.
Let us take care not to forget the differences between
cranking loads and standby capacity. We're also encouraged
to be mindful of the gross differences in individual requirements
for battery performance driven by overall system configuration
and pilot expectations for how the airplane is used.
The Odyssey is a quality product. I've visited their factory
in Mexico, MO and I was cognizant of Enersys battery performance
in our HBC products. With the right combination of preventative
maintenance, this batter (and no doubt others) will deliver
good value for their cost of acquisition and operation.
Thanks for sharing your experience with us!
Bob . . .
Message 9
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| Subject: | Re: B&C alternator diagnosis |
> do you know why these brushless alternator designs didn't use three
> phases like a modern BLDC motor?
This is pure speculation on my part; so correct me if wrong.
If the coils of a single phase alternator were rewired to make a 3 phase alternator,
then voltage output would be only 1/3 of the single phase voltage. In order
for a 3 phase alternator to have the same voltage output as a single phase
alternator, it would have to have two more windings of the same size. Then
it would weigh more and cost more.
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=386386#386386
Message 10
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| Subject: | More than you ever wanted to know about Li-on batteries |
http://powerelectronics.com/portable_power_management/battery_charger_ics/pr
oper_care_extends-li-ion-battery-0425/
-john-
Message 11
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| Subject: | More than you ever wanted to know about Li-on batteries |
http://tinyurl.com/6ca4c7 (there! that's better!)
-john-
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com] On
> Behalf Of John Loram
> Sent: Wednesday, October 31, 2012 11:14 AM
> To: aeroelectric-list@matronics.com
> Subject: AeroElectric-List: More than you ever wanted to know
> about Li-on batteries
>
> <johnl@loram.org>
>
> http://powerelectronics.com/portable_power_management/battery_
> charger_ics/pr
> oper_care_extends-li-ion-battery-0425/
>
> -john-
>
>
> Photoshare, and much much more:
>
>
>
>
Message 12
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| Subject: | Re: B&C alternator diagnosis |
At 01:02 PM 10/31/2012, you wrote:
> do you know why these brushless alternator designs didn't use three
> phases like a modern BLDC motor?
This is pure speculation on my part; so correct me if wrong.
If the coils of a single phase alternator were rewired to make a 3
phase alternator, then voltage output would be only 1/3 of the single
phase voltage. In order for a 3 phase alternator to have the same
voltage output as a single phase alternator, it would have to have
two more windings of the same size. Then it would weigh more and cost more.
Joe
--------
Joe Gores
The power output from an AC device is roughly proportional
to the weight of the active magnetic material (core), magnetic
strength and speed (rpm). I'm recalling from memory now but
back when I was winding my own transformers, a 1 pound core
was good for about 60 watts at 60 Hz. The same weight of core
in a 400 Hz system was good for 6.5 times that power . . .
400 watts. This assumes similar levels of magnetic flux
that can be carried in the core without saturation or
increases losses at higher frequencies.
An automotive alternator is already crafted as a 3-phase
device. The configuration requires that pole-pairs on the
rotating magnet come in some multiple of 3 (usually
6 pairs but can be more on larger machines).
The output voltage of any given widing is proportional
to speed x flux value x number of turns. When you 'rewind'
to get more voltage, it generally has to be done with
smaller wire . . . the winding window in the core is fixed.
The practical power output is not a linear function because
of heating effects of I-squared x R in the wires and the
windings ability to reject heat into the core and end turns.
There's not a great deal to be gained in power by going from
single to three-phase . . . it's that weight,flux,speed thing.
The BIG toe-stubber is pole piece configuration. The magnets
glued to the inside of the popular PM alternator shells (or
wound-field machines) are already optimized for their as-
manufactured condition. It takes more than a 'rewinding'
to morph from single to 3-phase configuration. But assuming
all other things are held the same, the watts-per-pound-per-
velocity will be the same for both configurations.
The BIG advantage of 3-phase is the smoother output with
simple full-wave rectification . . . about 5% ripple as
compared to 100% ripple for single-phase. But if the designer
sets out to do a clean piece of paper, 3-phase design it
will be only moderately more expensive. The power can be
a little better because the windings share duties . . . i.e.
there is never a time when current goes to zero in more than
one winding.
Bob . . .
Bob . . .
Message 13
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| Subject: | single vs. 3-phase alternators (forgot the picture!) |
At 01:02 PM 10/31/2012, you wrote:
> do you know why these brushless alternator designs didn't use three
> phases like a modern BLDC motor?
This is pure speculation on my part; so correct me if wrong.
If the coils of a single phase alternator were rewired to make a 3
phase alternator, then voltage output would be only 1/3 of the single
phase voltage. In order for a 3 phase alternator to have the same
voltage output as a single phase alternator, it would have to have
two more windings of the same size. Then it would weigh more and cost more.
Joe
--------
Joe Gores
The power output from an AC device is roughly proportional
to the weight of the active magnetic material (core), magnetic
strength and speed (rpm). I'm recalling from memory now but
back when I was winding my own transformers, a 1 pound core
was good for about 60 watts at 60 Hz. The same weight of core
in a 400 Hz system was good for 6.5 times that power . . .
400 watts. This assumes similar levels of magnetic flux
that can be carried in the core without saturation or
increases losses at higher frequencies.
An automotive alternator is already crafted as a 3-phase
device. The configuration requires that pole-pairs on the
rotating magnet come in some multiple of 3 (usually
6 pairs but can be more on larger machines).
Emacs!
The output voltage of any given winding is proportional
to speed x flux value x number of turns. When you 'rewind'
to get more voltage, it generally has to be done with
smaller wire . . . the winding window in the core is fixed.
The practical power output is not a linear function because
of heating effects of I-squared x R in the wires and the
windings ability to reject heat into the core and end turns.
There's not a great deal to be gained in power by going from
single to three-phase . . . it's that weight,flux,speed thing.
The BIG toe-stubber is pole piece configuration. The magnets
glued to the inside of the popular PM alternator shells (or
wound-field machines) are already optimized for their as-
manufactured condition. It takes more than a 'rewinding'
to morph from single to 3-phase configuration. But assuming
all other things are held the same, the watts-per-pound-per-
velocity will be the same for both configurations.
The BIG advantage of 3-phase is the smoother output with
simple full-wave rectification . . . about 5% ripple as
compared to 100% ripple for single-phase. But if the designer
sets out to do a clean piece of paper, 3-phase design it
will be only moderately more expensive. The power can be
a little better because the windings share duties . . . i.e.
there is never a time when current goes to zero in more than
one winding.
Bob . . .
Message 14
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| Subject: | Re: single vs. 3-phase alternators (forgot the picture!) |
Hi Bob
Is the small Walmart battery tender a good deal. It is quite a bit less exp
ensive than the battery tender brand, Your opinion?
Jim Robinson
Sent from my iPad
On Oct 31, 2012, at 3:11 PM, "Robert L. Nuckolls, III" <nuckolls.bob@aeroele
ctric.com> wrote:
> At 01:02 PM 10/31/2012, you wrote:
>
>
>
> > do you know why these brushless alternator designs didn't use three
> > phases like a modern BLDC motor?
>
> This is pure speculation on my part; so correct me if wrong.
> If the coils of a single phase alternator were rewired to make a 3 phase a
lternator, then voltage output would be only 1/3 of the single phase voltage
. In order for a 3 phase alternator to have the same voltage output as a si
ngle phase alternator, it would have to have two more windings of the same s
ize. Then it would weigh more and cost more.
> Joe
>
> --------
> Joe Gores
>
> The power output from an AC device is roughly proportional
> to the weight of the active magnetic material (core), magnetic
> strength and speed (rpm). I'm recalling from memory now but
> back when I was winding my own transformers, a 1 pound core
> was good for about 60 watts at 60 Hz. The same weight of core
> in a 400 Hz system was good for 6.5 times that power . . .
> 400 watts. This assumes similar levels of magnetic flux
> that can be carried in the core without saturation or
> increases losses at higher frequencies.
>
> An automotive alternator is already crafted as a 3-phase
> device. The configuration requires that pole-pairs on the
> rotating magnet come in some multiple of 3 (usually
> 6 pairs but can be more on larger machines).
>
> <1ddd5eb8.jpg>
>
>
> The output voltage of any given winding is proportional
> to speed x flux value x number of turns. When you 'rewind'
> to get more voltage, it generally has to be done with
> smaller wire . . . the winding window in the core is fixed.
>
> The practical power output is not a linear function because
> of heating effects of I-squared x R in the wires and the
> windings ability to reject heat into the core and end turns.
> There's not a great deal to be gained in power by going from
> single to three-phase . . . it's that weight,flux,speed thing.
>
> The BIG toe-stubber is pole piece configuration. The magnets
> glued to the inside of the popular PM alternator shells (or
> wound-field machines) are already optimized for their as-
> manufactured condition. It takes more than a 'rewinding'
> to morph from single to 3-phase configuration. But assuming
> all other things are held the same, the watts-per-pound-per-
> velocity will be the same for both configurations.
>
> The BIG advantage of 3-phase is the smoother output with
> simple full-wave rectification . . . about 5% ripple as
> compared to 100% ripple for single-phase. But if the designer
> sets out to do a clean piece of paper, 3-phase design it
> will be only moderately more expensive. The power can be
> a little better because the windings share duties . . . i.e.
> there is never a time when current goes to zero in more than
> one winding.
>
> Bob . . .
Message 15
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| Subject: | single vs. 3-phase alternators (forgot the picture!) |
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Message 16
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| Subject: | Re: vhf transponder interference |
thank you Bob
I've also found on "Google" that I should have a Notch filter installed, as per
Garmin, which I don't have....
I bought the plane 9 years ago as is....
I will check the coax cable during winter maintenance.
JP
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