Today's Message Index:
----------------------
1. 04:07 AM - WTB: PS PM-2000 intercom (Bob Gross)
2. 05:17 AM - alternatives to alternator circuit breakeralternatives to circuit breakers (RV4WGH@aol.com)
3. 06:15 AM - Re: Wherefore loadmeters? (Robert L. Nuckolls, III)
4. 10:58 AM - Re: Z19RB question (Robert L. Nuckolls, III)
5. 12:44 PM - How do I convert 14v DC to one-half volt? (Rogers, Bob J.)
6. 01:56 PM - Re: How do I convert 14v DC to one-half volt? (Rob Turk)
7. 03:28 PM - Re: 40 amp B&C Alternator wiring??? (Frank Stringham)
8. 03:47 PM - Re: How do I convert 14v DC to one-half volt? (Kevin Horton)
9. 03:54 PM - Re: How do I convert 14v DC to one-half volt? (Bob-tcw)
10. 04:52 PM - Re: How do I convert 14v DC to one-half volt? (The Kuffels)
11. 05:26 PM - Re: Z19RB question ()
12. 06:35 PM - Re: Z19RB question (Allen Fulmer)
13. 06:54 PM - Re: Wherefore loadmeters? (Sam Hoskins)
14. 07:04 PM - Re: How do I convert 14v DC to one-half volt? (Matt Prather)
15. 09:38 PM - Re: How do I convert 14v DC to one-half volt? (The Kuffels)
Message 1
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| Subject: | WTB: PS PM-2000 intercom |
Looking for a new or used PM-2000 or PM-3000 intercom.
Thanks
Bob
--
Using Opera's revolutionary e-mail client: http://www.opera.com/mail/
Message 2
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| Subject: | alternatives to alternator circuit breakeralternatives |
to circuit breakers
I got my ANL fuse and mount from B and C Aircraft
Wally Hunt
RV-4 Finishing Kit
Message 3
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| Subject: | Re: Wherefore loadmeters? |
At 05:39 PM 11/15/2007 -0600, you wrote:
>Does anyone know where Bob's articles on load meters are? I thought it
>might be in Chapter 7, but I couldn't find it.
>
>Sam
There are no articles specific to the topic
of loadmeters. In general, these are generic
ammeters but instead of calibrating the scale
plate in amperes, they are calibrated in percent
with 100% being full scale. See:
http://www.aeroelectric.com/Pictures/Instruments/Loadmeter_2.jpg
http://www.aeroelectric.com/Pictures/Instruments/loadmeter.jpg
https://matronics.com/aeroelectric/Catalog/9007-120-1_Loadmeter.jpg
The handy thing about this calibrating convention
is that a single instrument can be used with
any size alternator or generator. The full
scale sensitivity of instrument in amperes is
set by the size of the companion shunt. See:
http://www.aeroelectric.com/Pictures/Instruments/20-50_Shunt.jpg
A 20A shunt goes with alternators like the SD-20
and the instrument reads full scale when 100%
of the 20A machine is being taxed. It follows that
other sized alternators are monitored with the
appropriately sized shunt on the same instrument.
When the system is fitted with more than one
alternator, a single instrument can be switched
between the two sources, each fitted with the
appropriate sized shunt; wired as described here:
https://matronics.com/aeroelectric/Catalog/AEC/9007/AEC9007-700.pdf
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: | Re: Z19RB question |
At 10:51 PM 11/14/2007 -0600, you wrote:
>
>Bob,
>
>I am using your Z19RB architecture in my RV7 with Eggenfellner Subaru E6T.
>
>With the dual batteries and battery contactors in the rear of the plane and
>a single "fat wire" coming forward do you see any problem with putting a bus
>bar (like Stein's BB235: http://www.steinair.com/images/store/bb2305.jpg)
>near the firewall to terminate the fat wire?
>
>I would continue the fat wire from this bus bar to the starter contactor on
>the engine. The feed for the "Main Power Distribution Bus" would come from
>this bus rather than the starter contactor as depicted on Z19RB. This way I
>can do all the wiring (and testing) behind the firewall without having the
>engine mounted. I can see that I have created one more joint in the run
>from the batteries to the starter contactor but is that really a problem?
>
>Also, I have a pair of Gigavac GX11 contactors for the battery contactors
>and I was wondering how best to connect the coil ground wire (and optional
>NO/NC/COM contact wires if I choose) to the wires carrying them to the
>instrument panel mounted switch? Possible choices include:
> AMP "Mate-n-Lock" / Molex
> Mount a terminal strip with faston tabs by each contactor
> AMP Knife Splice?
My personal choice would be knife splices but either
of the other two technologies would probably be okay
if installed with good craftsmanship. My personal
design goals call for lowest parts count and minimized
process requirements. Knife splices and heat shrink
are the most attractive solutions to those goals.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 5
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| Subject: | How do I convert 14v DC to one-half volt? |
I am looking for some help or suggestions on how to reduce the normal
bus voltage of 12 to 14 volts DC in my experimental kitplane to one-half
volt for a circuit that activates the GPS OK flag in my CDI.
I have a portable moving-map GPS in my airplane. By sending the GPS
signal through a SMART COUPLER II by Porcine Associates, I get analog
left-right signals that will drive my Navaid autopilot and/or CDI.
However, in order for the CDI to function, it needs an electrical signal
to the GPS OK flag of more than 250 mV and less than 900 mV. I can use
the GPS OK signal from my Smart Coupler II, but it is a full 12-14 volts
(100 milliamps). THIS IS TOO MUCH VOLTAGE for my Course Deviation
Indicator GPS OK flag. I need to reduce the voltage to something
in-between the minimum and maximum allowable voltage (.25 - .90 volts).
My choice is .5 volts or one-half volt.
Can you tell me how to accomplish this? I found voltage regulators in
several supply catalogs (i.e., Jameco) that reduce voltage, but none of
them reduce it down to the needed level of one-half volt.
With appreciation,
Bob J. Rogers
Mustang II (almost ready to fly)
Message 6
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| Subject: | Re: How do I convert 14v DC to one-half volt? |
If you can settle for 0.7V then you could use a resistor and a diode in
series. Wire a 1K2 resistor (1/4W) to the output of your SC-II, then to a
standard silicon diode (1N4004 will do), then to Ground. The diode needs to
be conducting, so there's 0.7V across it. That is well within your margin.
So:
+12V Output o---[ 1K2 ]------(X)----->|-----o GND
The (X) marks your 0.7V signal to the CDI. The resistor causes a current of
about 10 mA to flow when there's 12V present. The diode is conducting and
causes a 0.7V drop.
Hope this helps,
Rob
----- Original Message -----
From: "Rogers, Bob J." <BRogers@fdic.gov>
Sent: Friday, November 16, 2007 6:39 PM
Subject: AeroElectric-List: How do I convert 14v DC to one-half volt?
> <BRogers@fdic.gov>
>
>
> I am looking for some help or suggestions on how to reduce the normal
> bus voltage of 12 to 14 volts DC in my experimental kitplane to one-half
> volt for a circuit that activates the GPS OK flag in my CDI.
>
> I have a portable moving-map GPS in my airplane. By sending the GPS
> signal through a SMART COUPLER II by Porcine Associates, I get analog
> left-right signals that will drive my Navaid autopilot and/or CDI.
> However, in order for the CDI to function, it needs an electrical signal
> to the GPS OK flag of more than 250 mV and less than 900 mV. I can use
> the GPS OK signal from my Smart Coupler II, but it is a full 12-14 volts
> (100 milliamps). THIS IS TOO MUCH VOLTAGE for my Course Deviation
> Indicator GPS OK flag. I need to reduce the voltage to something
> in-between the minimum and maximum allowable voltage (.25 - .90 volts).
> My choice is .5 volts or one-half volt.
>
> Can you tell me how to accomplish this? I found voltage regulators in
> several supply catalogs (i.e., Jameco) that reduce voltage, but none of
> them reduce it down to the needed level of one-half volt.
>
> With appreciation,
>
> Bob J. Rogers
> Mustang II (almost ready to fly)
>
>
>
Message 7
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| Subject: | 40 amp B&C Alternator wiring??? |
Just finished reading the instructions to wiring a B&C L-40 40 Amp Alternat
or and wanted some varification of my understanding as to my application.(F
ig. Z13)
(Question1...Why two male connectors on the alternator at the F position).
(Question2: How is the best way to ground the alternator?)
I would run an 18awg from the LR3 #4 position to the two F male connection
on the alternator per the following instructions:
5. Install the field plug on the harness. Refer to the diagram below for th
e correct terminal locations. Even though only one field connection is requ
ired, it is recommended both terminals be installed in the connector body t
o help stabilize the connector under high vibration conditions. It is furth
er recommended that the two terminals be jumped together for a redundant fi
eld connection. This may be accomplished by crimping a short (2 or 3") jump
er along with the field wire from the regulator in one of the terminals. Pl
ace a short length of heat shrink tubing over the wires before crimping. In
stall a second short piece of shrink tube over the free end of the jumper.
The other end of the jumper is then crimped in the second terminal. Solder
both terminals and the shrink the tubing over the wires and the crimped are
a of the terminals. Install the terminals in the slots in the connector bod
y. Check to see that the terminals have locked into the connector body. Ins
tall the connector in the alternator and be sure the connector locks into t
he alternator receptacle
Frank @ SGU RV7A 97%done 95% to go
Message 8
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| Subject: | Re: How do I convert 14v DC to one-half volt? |
On 16-Nov-07, at 12:39 PM, Rogers, Bob J. wrote:
> >
>
>
> I am looking for some help or suggestions on how to reduce the normal
> bus voltage of 12 to 14 volts DC in my experimental kitplane to one-
> half
> volt for a circuit that activates the GPS OK flag in my CDI.
>
> I have a portable moving-map GPS in my airplane. By sending the GPS
> signal through a SMART COUPLER II by Porcine Associates, I get analog
> left-right signals that will drive my Navaid autopilot and/or CDI.
> However, in order for the CDI to function, it needs an electrical
> signal
> to the GPS OK flag of more than 250 mV and less than 900 mV. I can
> use
> the GPS OK signal from my Smart Coupler II, but it is a full 12-14
> volts
> (100 milliamps). THIS IS TOO MUCH VOLTAGE for my Course Deviation
> Indicator GPS OK flag. I need to reduce the voltage to something
> in-between the minimum and maximum allowable voltage (.25 - .90
> volts).
> My choice is .5 volts or one-half volt.
>
> Can you tell me how to accomplish this? I found voltage regulators
> in
> several supply catalogs (i.e., Jameco) that reduce voltage, but none
> of
> them reduce it down to the needed level of one-half volt.
Assuming that very little current would be needed at this input, you
could simply use two resistors to make a voltage divider. Put two
resistors in series, with one of them approximately 24 times the
resistance of the other one (the range of required voltages is quite
large, so you have a fair bit of leeway on this value of 24 times).
Hook one end of the big resistor to 14v, and one end of the small
resistor to ground. Pick off the voltage you need where the two
resistors join up. Make sure the sum of the two resistors is high
enough to limit the current flow through the divider circuit to an
acceptably low level. The power draw will be very low as long as you
keep the current low by choosing high enough values for the
resistors. E.g, if the total of the two resistors is 1000 ohms, the
current would be 0.014 amps, and the power dissipated in the large
resistor would be about 0.19 watt, so 1/4 watt resistors would work.
I'm not sure what the commonly available resistor values are, so I
won't try to suggest which ones to look for.
--
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
Message 9
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| Subject: | Re: How do I convert 14v DC to one-half volt? |
Here's a little circuit to act as a voltage detector, resistor should be
at least 1/4 watt rated.
-Bob Newman
www.tcwtech.com
Message 10
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| Subject: | Re: How do I convert 14v DC to one-half volt? |
Bob,
<< bus voltage activates the GPS OK flag in my CDI. >>
Rob Turk's method of tapping the voltage between a resistor and a
forward biased diode is an excellent way to get a low current
regulated voltage. For your application an even simpler way will
work.
A sufficiently high resistor in the line between the Smart
Coupler output and the CDI input will do the job. I would use
the highest resistor which turns on the flag with a 9 volt
battery. To be on the safe side, I would start with at least
220k ohms and slowly work my way down until the battery reliably
turns on the flag. Almost any local amateur radio operator will
have a selection of resistors, or small variable resistors, with
which to find the right value.
If the CDI documentation specifies the current drawn by the flag
then you can use Ohm's law to calculate the resistor:
resistor equals voltage divided by current
If the current is given in milliamps (ma) then the resulting
resistor is in kilohms (kohm). But even then I would use the
battery/test resistor method. Setting the resistor value with 9
volts gives you a margin that if the buss voltage is high enough
to run the coupler then the output is high enough to display the
flag.
Tom Kuffel
Message 11
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Bob,
Re: the Eggenfellner installation and Z19. Eggenfellner recommends a 200
amp ANL fuse close to the positive battery post on each battery. I don't
see this reflected in your design, so in your opinion is this justified
or just an uber precaution?
Thanks
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Robert L. Nuckolls, III
Sent: Friday, November 16, 2007 12:30 PM
Subject: Re: AeroElectric-List: Z19RB question
--> <nuckolls.bob@cox.net>
At 10:51 PM 11/14/2007 -0600, you wrote:
>--> <afulmer@charter.net>
>
>Bob,
>
>I am using your Z19RB architecture in my RV7 with Eggenfellner Subaru
>E6T.
>
>With the dual batteries and battery contactors in the rear of the plane
>and a single "fat wire" coming forward do you see any problem with
>putting a bus bar (like Stein's BB235:
>http://www.steinair.com/images/store/bb2305.jpg)
>near the firewall to terminate the fat wire?
>
>I would continue the fat wire from this bus bar to the starter
>contactor on the engine. The feed for the "Main Power Distribution
>Bus" would come from this bus rather than the starter contactor as
>depicted on Z19RB. This way I can do all the wiring (and testing)
>behind the firewall without having the engine mounted. I can see that
>I have created one more joint in the run from the batteries to the
>starter contactor but is that really a problem?
>
>Also, I have a pair of Gigavac GX11 contactors for the battery
>contactors and I was wondering how best to connect the coil ground wire
>(and optional NO/NC/COM contact wires if I choose) to the wires
>carrying them to the instrument panel mounted switch? Possible choices
include:
> AMP "Mate-n-Lock" / Molex
> Mount a terminal strip with faston tabs by each contactor
> AMP Knife Splice?
My personal choice would be knife splices but either
of the other two technologies would probably be okay
if installed with good craftsmanship. My personal
design goals call for lowest parts count and minimized
process requirements. Knife splices and heat shrink
are the most attractive solutions to those goals.
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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Thanks Bob,
Any thoughts on the first question?
>>>> I am using your Z19RB architecture in my RV7 with
>>>> Eggenfellner Subaru E6T.
>>>>
>>>> With the dual batteries and battery contactors in the rear
>>>> of the plane and
>>>> a single "fat wire" coming forward do you see any problem
>>> with putting a bus
>>>> bar (like Stein's BB235:
>>> http://www.steinair.com/images/store/bb2305.jpg)
>>>> near the firewall to terminate the fat wire?
>>>>
>>>> I would continue the fat wire from this bus bar to the
>>> starter contactor on
>>>> the engine. The feed for the "Main Power Distribution Bus"
>>> would come from
>>>> this bus rather than the starter contactor as depicted on
>>> Z19RB. This way I
>>>> can do all the wiring (and testing) behind the firewall
>>> without having the
>>>> engine mounted. I can see that I have created one more
>>> joint in the run
>>>> from the batteries to the starter contactor but is that
>>> really a problem?
>>>>
Message 13
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| Subject: | Re: Wherefore loadmeters? |
Thanks for clearing that up for me.
Sam
On Nov 16, 2007 7:53 AM, Robert L. Nuckolls, III <nuckolls.bob@cox.net>
wrote:
> nuckolls.bob@cox.net>
>
> At 05:39 PM 11/15/2007 -0600, you wrote:
>
> >Does anyone know where Bob's articles on load meters are? I thought it
> >might be in Chapter 7, but I couldn't find it.
> >
> >Sam
>
> There are no articles specific to the topic
> of loadmeters. In general, these are generic
> ammeters but instead of calibrating the scale
> plate in amperes, they are calibrated in percent
> with 100% being full scale. See:
>
> http://www.aeroelectric.com/Pictures/Instruments/Loadmeter_2.jpg
>
> http://www.aeroelectric.com/Pictures/Instruments/loadmeter.jpg
>
> https://matronics.com/aeroelectric/Catalog/9007-120-1_Loadmeter.jpg
>
>
> The handy thing about this calibrating convention
> is that a single instrument can be used with
> any size alternator or generator. The full
> scale sensitivity of instrument in amperes is
> set by the size of the companion shunt. See:
>
> http://www.aeroelectric.com/Pictures/Instruments/20-50_Shunt.jpg
>
> A 20A shunt goes with alternators like the SD-20
> and the instrument reads full scale when 100%
> of the 20A machine is being taxed. It follows that
> other sized alternators are monitored with the
> appropriately sized shunt on the same instrument.
>
> When the system is fitted with more than one
> alternator, a single instrument can be switched
> between the two sources, each fitted with the
> appropriate sized shunt; wired as described here:
>
> https://matronics.com/aeroelectric/Catalog/AEC/9007/AEC9007-700.pdf
>
> Bob . . .
>
>
> ----------------------------------------)
> ( . . . a long habit of not thinking )
> ( a thing wrong, gives it a superficial )
> ( appearance of being right . . . )
> ( )
> ( -Thomas Paine 1776- )
> ----------------------------------------
>
>
--
Sam Hoskins
www.MistakeProofing.Net
www.MistakeProofing.net/blog/
618-967-0016 ph.
312-212-4086 fax
Message 14
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| Subject: | Re: How do I convert 14v DC to one-half volt? |
Probably unlikely, but the CDI might have a FET input which would have
extremely high equivalent resistance (or low leakage current - in the nano
Amps), and the IV curve may be non-linear. The output leakage current on
the Smart Coupler may be significantly higher than the input
leakage/operating current on the CDI. If this were the case, no matter
how high the resistance value of the interconnect resistor you're
proposing, you may not be able to control the voltage on the CDI. A
voltage divider is a safer way to go (at least for prototyping) though
your proposal will probably work.
Matt-
> <kuffel@cyberport.net>
>
> Bob,
>
> << bus voltage activates the GPS OK flag in my CDI. >>
>
> Rob Turk's method of tapping the voltage between a resistor and a
> forward biased diode is an excellent way to get a low current
> regulated voltage. For your application an even simpler way will
> work.
>
> A sufficiently high resistor in the line between the Smart
> Coupler output and the CDI input will do the job. I would use
> the highest resistor which turns on the flag with a 9 volt
> battery. To be on the safe side, I would start with at least
> 220k ohms and slowly work my way down until the battery reliably
> turns on the flag. Almost any local amateur radio operator will
> have a selection of resistors, or small variable resistors, with
> which to find the right value.
>
> If the CDI documentation specifies the current drawn by the flag
> then you can use Ohm's law to calculate the resistor:
>
> resistor equals voltage divided by current
>
> If the current is given in milliamps (ma) then the resulting
> resistor is in kilohms (kohm). But even then I would use the
> battery/test resistor method. Setting the resistor value with 9
> volts gives you a margin that if the buss voltage is high enough
> to run the coupler then the output is high enough to display the
> flag.
>
> Tom Kuffel
>
>
Message 15
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| Subject: | Re: How do I convert 14v DC to one-half volt? |
Matt,
<< high resistor in the line >> << CDI might have a FET input
which would have extremely high equivalent resistance .. If this
were the case .. you may not be able to control the voltage >>
My King KI209 specifies a flag input impedance of 1k. So at
least for this instrument a single resistor should work. But
issues like this are why I suggest he try the 9 volt battery/test
resistors method first. No objection to the 2nd resistor or
forward biased diode method (in fact my first thought) but in
this application simplest might work just fine.
Tom Kuffel
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