Today's Message Index:
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1. 09:48 AM - Re: Dan's Jabiru 3300 Wiring Schematic (user9253)
2. 09:49 AM - Re: Dan's Jabiru 3300 Wiring Schematic (Robert L. Nuckolls, III)
3. 10:33 AM - Re: Dan's Jabiru 3300 Wiring Schematic (messydeer)
4. 11:34 AM - Collins 350A (jtortho@aol.com)
5. 06:01 PM - Re: Dan's Jabiru 3300 Wiring Schematic (user9253)
6. 06:24 PM - Mason City, Iowa Aero-Electric seminar (Kesley Electric)
7. 07:53 PM - Re: Dan's Jabiru 3300 Wiring Schematic (messydeer)
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| Subject: | Re: Dan's Jabiru 3300 Wiring Schematic |
Dan,
You are right. You do have two pole switches. I was looking at the wrong (original)
schematic that you posted and not the updated one. I was wondering why
no one else commented on the hot wire going to the magneto shield. Looking
at the updated schematic with a file size of 324.58 KB, the starting circuit
and mag switch circuit look fine. I see nothing unsafe.
> It was pointed out to me that my adaptation doesn't allow for dual mags at starting.
Unless I am missing something, both mags will be on when the switches are in the
start position.
> As I understand it, the stand alone instrument will give the system voltage without
an additional shunt. So I assume voltage would be measured on either side
of it's own load,
I'm not sure what you mean by that. But the EFIS should provide the voltage readout without connecting any wires other than those that power up the EFIS. The IOEX seems like extra weight and expense just to measure current. I read the calibration procedure at http://www.mglavionics.com/IOEX.pdf. The most useful location for a current sensor is in the alternator output. The shunt could be in series with the alternator output between the 10000 microfarad capacitor and the 25amp fuse on your schematic. The easy calibration method would be to use a shunt of known resistance. Using the aircraft wire in lieu of a shunt will save weight and expense but will make calibrating more difficult because they want the unit calibrated with the engine off. You would have to temporarily remove that #8awg wire from the capacitor and connect it to a battery and measure the current with a portable meter and enter that information into the EFIS. Actually 8awg is much too big as Bob said. If you intend to use that wire as a shunt, it needs to be small enough (or long enough) to have a voltage drop from end to end. Perhaps 16awg would work. Regardless of the type of shunt used, the signal wires going back to the IOEX need to be protected with fuses or fuselinks. The positive signal wire should be connected to the end of the shunt closest to the capacitor.
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=259083#259083
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| Subject: | Re: Dan's Jabiru 3300 Wiring Schematic |
If I want to measure current elsewhere, I need to get a separate
shunt, or as they suggest, use the part of the system itself as a
shunt. With any luck, I'll upload a their diagram of this.
Where do they suggest this? I've poked around in
their downloads and was unable to find an install
manual for their i/o extender.
So now I can monitor current wherever I place this shunt. Well, not
quite. I have to buy their Input Output eXtender (IOX), a decent
sized piece of hardware that the shunt wires plug into. There are
several other fancy things that can be done with this IOX, but for
me, there wouldn't be much else to use it for.
Then leave it off. It's a lot of money to spend
for so little useful data.
If you can accurately know the system voltage, then
it's easy to deduce whether or not the alternator
is keeping up, is over-burdened, or broke.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
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| Subject: | Re: Dan's Jabiru 3300 Wiring Schematic |
Bob and Joe:
Joe gave the link, I think. Here's what I read, starting on page 3:
> Current monitoring
> The I/O Extender provides a bi-directional current monitoring system. This is
intended to
> measure the charge and discharge currents to and from the aircraft battery.
> Current is measured indirectly by measuring the small voltage drop created by
current flowing
> through a suitable shunt resistor. Typical shunt resistors are in the range of
0.010 ohm (10
> milli-ohm) to 30 milli ohm. However, the current measuring system has been designed
to
> accept any shunt. In particular, you can usually use the +12V supply cable from
the battery +
> terminal to the power distribution system as a suitable shunt. Connect the I/O
Extender shunt
> terminals using two wires (these can be thin wires) to each side of the cable
connecting the
> battery + terminal to the current distribution system.
> In this scheme, large, temporary current users such as electrical starter motors
should NOT
> be routed through the shunt. These should be wired directly to the battery via
their starter
> solenoids using adequately dimensioned cable.
> Calibrating the shunt (known current):
> The I/O Extender needs to know the resistance of the shunt in order to correctly
calculate the
> current flowing through it.
> Our suggested method involves using a cheap digital or analog multimeter (they
tend to have
> a 10A DC range). Wire this meter in series with the shunt and switch some electrical
users on
> so you have a reasonable current flow (for example 2 4 A). Do not run the engine
or have
> any charging active for this calibration.
> Using the connected EFIS, activate the current calibration and enter the amount
of current
> your meter is reporting.
> Calibrating the shunt (known resistance):
> If you are using a shunt with a known resistance, use the provided functions
in the EFIS
> system to set the shunt resistance value. This method does not require the use
of a current
> meter for calibration although we would recommend that you verify the current
reported using
> a current meter to ensure that your shunt resistance is correct.
> Calibrating the zero current point.
> This is a calibration that has happened at the factory but you can perform it
yourself if
> needed. The idea is to ensure that the I/O Extender returns a 0 current flow
if no current is
> flowing through the shunt.
> For this, disconnect one of the wires to the shunt and connect it to the other
side of the shunt.
> Both wires will not be connected to the same side of the shunt (it does not matter
which side).
> Once this has been done, perform the set current zero calibration function in
your EFIS
> system.
> Polarity of the shunt wires:
> For correct operation the shunt wires should be connected so that Shunt + terminal
connects
> to the battery + terminal and Shunt connects to the load.
> This will ensure that charge current with be reflected as positive current reading
while
> discharge current will be reflected as negative reading.
> About current measurement:
> All current calibration should be done using DC current.
> The I/O Extender system measures average current. This is NOT RMS. Many meters
> cannot accurately measure A/C or pulsating currents. They can only give a good
reading if
> they are measuring a sine-wave (such as mains power).
> Current through a typical aircraft shunt is best described as pulsed A/C. The
charging
> system provides short but powerful current bursts to the battery while the time
between the
> bursts the battery supplies current to the load. The battery is effectively changing
between
> charge and discharge all the time very rapidly.
> The I/O Extender averages current measurements in both directions and returns
the
> averaged result of this. This shows the net charge or discharge current.
> A normal battery, when fully charged, will show a small residual charging current
(assuming
> the charger is not overcharging the battery). This charging current is required
to maintain the
> battery charge as it is supplying current all the time (between the pulsed charge
current). The
> battery, depending on its chemistry has a charge efficiency of around 80% so
it needs a
> constant charge under these conditions.
> Unless I am missing something, both mags will be on when the switches are in
the start position.
The file "note 2 starter mods 3.pdf" diagram 3 shows the upper switch closing the
starter circuit, but the switches mag circuit is grounded by the red jumper.
It may be confusing because I also label both switches as 'left mag'.
So I've played around with the mag wiring and replaced the lower single pole switch
with another 2-5 double pole switch. Please see how the new wiring looks
in the attachment here.
I hope I have it setup so the left mag would be used as the main start switch with
both mags hot. The right switch would crank but not start, if the left switch
is left off. The engine could also be started by the right switch when the
left mag is 'on'. I don't intend for this config to ever be used, as it would
then only have one mag firing.
--------
Dan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=259086#259086
Attachments:
http://forums.matronics.com//files/note_2_both_mags_start_mod_201.pdf
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This is? more avionics then electric but a question anyway.
Wiring a Garmin 300 xl to a collins ind 350-A indicator.?? The Garmin does not
provide a? resolver H output.
What is the function pf resolver H? ( or any of the other Resolvers)?
Is it necessary in this setting?
Jim Timoney
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| Subject: | Re: Dan's Jabiru 3300 Wiring Schematic |
Dan,
In addition to the 4 combinations that you have in http://forums.matronics.com/download.php?id=17457
there are 4 more:
Left switch down and right one centered
Left switch centered and right one up
Left switch centered and right one down
Left switch up and right one down
Would there ever be a situation where one would want to start the engine on the
right mag without using the left switch?
There could be a safety issue if someone unfamiliar with your plane turned on a
mag switch and the engine cranked unexpectedly.
You have put a lot of thought into this and did a good job. It is complicated
and would be hard for me to remember what switch position does what. Of course
I suffer from CRS syndrome. :) If it were my plane, I would use two single-pole,
single-throw switches for the magnetos, and a momentary push button in
series with a security switch to start the engine. But to each his own.
Getting back to the The I/O Extender.
> . . . . .provides a bi-directional current monitoring system. This is intended
to measure the charge and discharge currents to and from the aircraft battery.
Measuring the current in or out of the battery is not very useful information because
the battery does not supply energy to the aircraft under normal operations,
the alternator does. Most homebuilders measure the output of the alternator,
not the charging current of the battery. Even though MGL suggests installing
a shunt in the battery circuit, their ammeter will work just fine with the
shunt installed in the alternator output wire.
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=259138#259138
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| Subject: | Mason City, Iowa Aero-Electric seminar |
EAA Chapter 94 in Mason City, Iowa, will be hosting Bob's weekend
Aero-Electric Seminar on October 17-18, 2009.
See Bob's website for complete details.
The classroom will be a spacious, well appointed hangar at the Mason City
airport.
Hope to see some of you there. Feel free to contact me if you have
questions.
Tom Barter
Kesley, IA
kesleyelectric@iowatelecom.net
Message 7
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| Subject: | Re: Dan's Jabiru 3300 Wiring Schematic |
Hey, Joe :-)
My objective is to explore the possibility of eliminating the push start button
by integrating it's function into two 2-5 switches. I am indeed concerned about
the intuitiveness (not sure if that's a word, but let's go with it) of the
start sequence.
There are two separate switches, each capable of starting the engine. In a 3 switch
system, where there is a push starter switch, the mag switches are flipped
into the 'on' position and the starter button is pushed. The same thing here,
mag switches are flipped into the 'on' position. The only thing that differs
is there is no start button. Instead lift the left switch into the momentary
'start' position, which to me sounds very similar to starting my car which also
has a momentary 'start' feature. If I forget and start with the right mag, no
worries, it will start.
And if there is an in-flight need to restart and it doesn't start by the windmilling
prop, holding either start switch up in the start/crank position would work.
To summarize, when starting, flip both mag switches on. Lift either one of them
to the momentary 'start/crank' position and release when it's started. Mag
check by flipping one off, return it to on, then repeat with the other mag. Flipping
both switches down to the 'off' position will kill the engine.
To me, this sounds fairly simple. But I am a bit subjective, since it is my idea.
And, I'm not a pilot, have never started an airplane engine. This is why I'm
posting. Gives me some perspective on things by people who are much more intimate
with airplanes.
Regarding your list of combinations, I'm not sure what you're getting at. Yes,
there are several possible switch combinations. There are also several combinations
of a 3 switch start system that are seldom or never used:
1. left mag on, right mag off, start button not engaged
2. left mag on, right mag off, start button engaged
3. left mag off, right mag off, start button engaged
etc.
My point is there are several useless switch positions in either a two- or three-switch
starting system. If I feel overburdened by either one of these systems,
I could get a single switch that will eventually start if I keep turning it
clockwise, and will eventually kill the engine if I turn it counterclockwise.
Man, so now I'll have to get an old fashioned watch with a dial [Crying or Very
sad] And then I'll have to make sure its hands only move clockwise.
--------
Dan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=259153#259153
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