Today's Message Index:
----------------------
1. 03:44 AM - Re: Flap circuit relay questions (KITFOXZ@aol.com)
2. 05:36 AM - Re: Flap circuit relay questions (David Swartzendruber)
3. 06:16 AM - ALT Field Breaker.... (Jack Lockamy)
4. 06:28 AM - KX-155 Overload?? (JSMONDAY@aol.com)
5. 07:00 AM - Re: Flap circuit relay questions (KITFOXZ@aol.com)
6. 07:00 AM - Re: ALT Field Breaker....and Diodes (Dale Martin)
7. 07:53 AM - diodes on relay coils (David Swartzendruber)
8. 08:28 AM - Re: Flap circuit relay questions (Richard Tasker)
9. 08:43 AM - unsuscribeRe: Flap circuit relay questions (Stan and Lindy)
10. 12:33 PM - world's easiest question (Troy Scott)
11. 12:33 PM - personal ELT (Troy Scott)
12. 03:46 PM - Re: personal ELT (Benford2@aol.com)
13. 06:32 PM - Re: personal ELT (richard@riley.net)
14. 07:04 PM - Re: personal ELT (Dan Branstrom)
15. 07:17 PM - Re: personal ELT (Kevin Horton)
16. 10:33 PM - Re: personal ELT (richard@riley.net)
Message 1
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| Subject: | Re: Flap circuit relay questions |
--> AeroElectric-List message posted by: KITFOXZ@aol.com
Hello Bob,
Re: relay bounce. I always believed that relay bounce was caused by poor
inductive "kick" suppression. I can swear it was a listed item in my old text
book about relay operation. Years ago, I worked on mechanically tuned avionics
boxes that were the state of the art in our Naval Aircraft. RCA, Collins,
Bendix, Honeywell and others of the manufacturers used neons to handle
suppressing the coils on those units. I always assumed the "bounce" I would see
from
time to time was caused by the neon not dropping the relay coil's voltage low
enough between cycles.
Some of those old boxes needed very fast stop pulses to get the mechanical
mechanisms to halt in just the right spot for accurate tuning. I would imagine
that you are very familiar with this scenerio. (thank God for varactors!)
The neons were used, I assume for their speed. Perhaps the "bounce" I would
see was in fact caused by worn (burned) contacts on the controlling device --
not able to give me a clean break at off time? We used to take those suckers
apart and burnish the contacts as needed. The kids of today don't know half
of the school of hard knocks that went into producing the modern GPS receiver!
John P. Marzluf
Columbus, Ohio
Kitfox Outback (out back in the garage)
Message 2
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| Subject: | Flap circuit relay questions |
--> AeroElectric-List message posted by: "David Swartzendruber" <dswartzendruber@earthlink.net>
Suppression devices on a relay coil can only slow down the release of
the relay contacts. The goal is to suppress the transient enough to
protect the control switch contacts without degrading the performance of
the relay. That is why some prefer not to use just a diode, but will
put a zener in series with the diode, or use an MOV or transorb.
Dave
>
> Hello Bob,
>
> Re: relay bounce. I always believed that relay bounce was caused by
poor
> inductive "kick" suppression.
> RCA, Collins,
> Bendix, Honeywell and others of the manufacturers used neons to handle
> suppressing the coils on those units. I always assumed the "bounce" I
> would see from
> time to time was caused by the neon not dropping the relay coil's
voltage
> low
> enough between cycles.
>
> Some of those old boxes needed very fast stop pulses to get the
mechanical
> mechanisms to halt in just the right spot for accurate tuning. I
would
> imagine
> that you are very familiar with this scenerio. (thank God for
varactors!)
>
> The neons were used, I assume for their speed.
>
> John P. Marzluf
> Columbus, Ohio
> Kitfox Outback (out back in the garage)
>
Message 3
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| Subject: | ALT Field Breaker.... |
--> AeroElectric-List message posted by: "Jack Lockamy" <jacklockamy@att.net>
Will pulling the ALT Field Breaker (5A) shut down the ALT in an over-voltage or
runaway alternator situation? If not.... what does happen?
Thanks,
Jack Lockamy
Camarillo, CA
RV-7A Wiring
Message 4
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| Subject: | KX-155 Overload?? |
--> AeroElectric-List message posted by: JSMONDAY@aol.com
I am training in a Piper Warrior (a friends plane) and while transmitting on
final KX-155 there was a crackle and what appeared to be an overload and the
altermator field and output breakers popped. Got everything restored, but the
KX-155 NavCom was the only thing that did not want to come back up. Panel
does not light, turning on and off, you can hear a click in the speaker, and
some deflection in the CDI. Is there anything that is east to check on these
radios if I remove it? i.e. reset breaker on back, internal fuses etc.??? Will
be pulling it out either today or tomorrow, hope to do a quick preliminary
look and see and hopefully save some time and money on the repair!
Thanks,
John Monday
KR2S
Laguna Beach, CA
Message 5
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| Subject: | Re: Flap circuit relay questions |
--> AeroElectric-List message posted by: KITFOXZ@aol.com
In a message dated 3/5/2004 8:37:21 AM Eastern Standard Time,
dswartzendruber@earthlink.net writes:
Suppression devices on a relay coil can only slow down the release of
the relay contacts. The goal is to suppress the transient enough to
protect the control switch contacts without degrading the performance of
the relay. That is why some prefer not to use just a diode, but will
put a zener in series with the diode, or use an MOV or transorb.
Dave
No, Dave, I have always understood that the objective is to provide an
alternate current path for the relay coil's flux to be relieved. A device that
accomplishes this the fastest is best. With no suppression device at all, the
opening control contacts impede the quick discharge of the coil's energy and that
energy burns the opening contacts. Any suppression device will speed things
up over the high resistance of open (or opening) control contacts. Right?
Please tell me if I am all wet here!
John P. Marzluf
Columbus, Ohio
Kitfox Outback (out back in the garage)
Message 6
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| Subject: | Re: ALT Field Breaker....and Diodes |
--> AeroElectric-List message posted by: "Dale Martin" <niceez@cableone.net>
It sure shuts mine off right now!
With all this talk of using diodes and such on contacts to save switches, I
wonder if the switch manufactures take that into consideration when
designing and producing a switch? It would be foolish not to. I think it
is a good idea to use diodes and want to say "Thank You" everyone here for
the discussions so we amateur electricians gain more important knowledge.
After 17 years of great service the Long-EZ has had the instrument panel
removed and all of the wiring for updates and to apply the current
technology. Can't wait to see how much weight has been discarded.
Blue Skies,
Dale Martin
Lewiston, ID
LEZ-235
----- Original Message -----
From: "Jack Lockamy" <jacklockamy@att.net>
Subject: AeroElectric-List: ALT Field Breaker....
> --> AeroElectric-List message posted by: "Jack Lockamy"
<jacklockamy@att.net>
>
> Will pulling the ALT Field Breaker (5A) shut down the ALT in an
over-voltage or runaway alternator situation? If not.... what does happen?
>
> Thanks,
> Jack Lockamy
> Camarillo, CA
> RV-7A Wiring
>
>
Message 7
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| Subject: | diodes on relay coils |
--> AeroElectric-List message posted by: "David Swartzendruber" <dswartzendruber@earthlink.net>
>
> In a message dated 3/5/2004 8:37:21 AM Eastern Standard Time,
> dswartzendruber@earthlink.net writes:
> Suppression devices on a relay coil can only slow down the release of
> the relay contacts. The goal is to suppress the transient enough to
> protect the control switch contacts without degrading the performance
of
> the relay. That is why some prefer not to use just a diode, but will
> put a zener in series with the diode, or use an MOV or transorb.
>
> Dave
> No, Dave, I have always understood that the objective is to provide an
> alternate current path for the relay coil's flux to be relieved. A
device
> that
> accomplishes this the fastest is best. With no suppression device at
all,
> the
> opening control contacts impede the quick discharge of the coil's
energy
> and that
> energy burns the opening contacts. Any suppression device will speed
> things
> up over the high resistance of open (or opening) control contacts.
Right?
> Please tell me if I am all wet here!
>
> John P. Marzluf
> Columbus, Ohio
> Kitfox Outback (out back in the garage)
>
Yes, the suppression device provides an alternate path for the coil
current. Without it, the stored energy in the inductive coil winding is
dissipated as arcing across the contacts of the control switch. With
it, the energy is dissipated in the suppression device because the
voltage never gets high enough to arc across the switch contacts. The
higher the voltage across the suppression device, the faster the energy
is dissipated and the faster the coil current decays. The key to fast
release of the relay contacts is fast decay of the coil current. This
is because the coil current is what is creating the magnetic flux that
is holding the relay contacts closed. Adding a diode across the coil of
a relay slows it down because it slows down the decay of the coil
current.
Bob has determined that the diode on the coil does not slow the opening
of the relay contacts significantly enough to have an effect on relay
performance. Personally, I have no data to back up a statement
concerning how much the relay performance is affected by the diode vs.
no diode vs. a transorb, MOV, or Zener.
Dave
Message 8
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| Subject: | Re: Flap circuit relay questions |
--> AeroElectric-List message posted by: Richard Tasker <retasker@optonline.net>
Sorry, but you are saturated :-) . Actually your understanding of the
objective is right on, but your understanding of what happens is not.
Any device added to a relay coil to eliminate the relay coil "kickback"
will cause the relay coil current to continue to flow and slow the relay
opening down.
CAUTION, heavy electrical discussion follows:
When the relay coil power is interrupted, the coil still has a certain
amount of energy stored in the coil. This is 1/2*L*I2, where L is the
inductance of the coil and I2 is the current flowing in the coil
squared. The current has to be reduced to some smaller value before the
relay contacts will open. The current flowing in the coil will "want"
to continue to flow (since it is an inductor)and as long as this current
continues to flow the relay will remain energized. If one leaves the
relay with no suppression, the voltage will rise to some arbitrarily
high value and the energy will be dissipated relatively quickly (energy
flow is directly related to the voltage * current, so with a high
voltage the energy dissipates quickly). If one adds a diode to minimize
the voltage rise then the voltage rise is only 0.7V or so and it takes
much longer for the energy to dissipate. That is why some people prefer
to use MOVs or transorbs. These allow the voltage to rise to some
intermediate value - high enough to dissipate the energy relatively
quickly, but low enough to protect the relay control circuitry (switch
contacts, electronics, etc.).
End of discussion.
So, if you can stand to allow a relatively minor increase in the time
that the relay takes to open (10s of milliseconds) then a diode is the
safest way to go. Otherwise, some other voltage limiting device is
recommended.
Dick Tasker
KITFOXZ@aol.com wrote:
>Dave
>No, Dave, I have always understood that the objective is to provide an
>alternate current path for the relay coil's flux to be relieved. A device that
>accomplishes this the fastest is best. With no suppression device at all, the
>opening control contacts impede the quick discharge of the coil's energy and that
>energy burns the opening contacts. Any suppression device will speed things
>up over the high resistance of open (or opening) control contacts. Right?
>Please tell me if I am all wet here!
>
>John P. Marzluf
>Columbus, Ohio
>Kitfox Outback (out back in the garage)
>
>
Message 9
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| Subject: | Re: Flap circuit relay questions |
--> AeroElectric-List message posted by: Stan and Lindy <stanlindy@comcast.net>
unsuscribeAt 11:27 AM 3/5/2004 -0500, you wrote:
>--> AeroElectric-List message posted by: Richard Tasker
><retasker@optonline.net>
>
>Sorry, but you are saturated :-) . Actually your understanding of the
>objective is right on, but your understanding of what happens is not.
>
>Any device added to a relay coil to eliminate the relay coil "kickback"
>will cause the relay coil current to continue to flow and slow the relay
>opening down.
>
>CAUTION, heavy electrical discussion follows:
>When the relay coil power is interrupted, the coil still has a certain
>amount of energy stored in the coil. This is 1/2*L*I2, where L is the
>inductance of the coil and I2 is the current flowing in the coil
>squared. The current has to be reduced to some smaller value before the
>relay contacts will open. The current flowing in the coil will "want"
>to continue to flow (since it is an inductor)and as long as this current
>continues to flow the relay will remain energized. If one leaves the
>relay with no suppression, the voltage will rise to some arbitrarily
>high value and the energy will be dissipated relatively quickly (energy
>flow is directly related to the voltage * current, so with a high
>voltage the energy dissipates quickly). If one adds a diode to minimize
>the voltage rise then the voltage rise is only 0.7V or so and it takes
>much longer for the energy to dissipate. That is why some people prefer
>to use MOVs or transorbs. These allow the voltage to rise to some
>intermediate value - high enough to dissipate the energy relatively
>quickly, but low enough to protect the relay control circuitry (switch
>contacts, electronics, etc.).
>
>End of discussion.
>
>So, if you can stand to allow a relatively minor increase in the time
>that the relay takes to open (10s of milliseconds) then a diode is the
>safest way to go. Otherwise, some other voltage limiting device is
>recommended.
>
>Dick Tasker
>
>
>KITFOXZ@aol.com wrote:
>
> >Dave
> >No, Dave, I have always understood that the objective is to provide an
> >alternate current path for the relay coil's flux to be relieved. A
> device that
> >accomplishes this the fastest is best. With no suppression device at
> all, the
> >opening control contacts impede the quick discharge of the coil's energy
> and that
> >energy burns the opening contacts. Any suppression device will speed
> things
> >up over the high resistance of open (or opening) control contacts. Right?
> >Please tell me if I am all wet here!
> >
> >John P. Marzluf
> >Columbus, Ohio
> >Kitfox Outback (out back in the garage)
> >
> >
>
>
Message 10
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| Subject: | world's easiest question |
--> AeroElectric-List message posted by: "Troy Scott" <tscott1217@bellsouth.net>
Eric,
I know that some manufacturers actually run the circuit boards through a
dishwasher, just like the one in your hour house, before plugging in the
ICs. They come out really nice.
Regards,
Troy Scott
tscott1217@bellsouth.net
Message 11
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--> AeroElectric-List message posted by: "Troy Scott" <tscott1217@bellsouth.net>
Gentlemen,
If I carry a personal EPIRB, do I still have to install a standard aircraft
EPIRB? Probably so..... But I wonder if one of the little personal EPIRBs
could be adapted for use in an Experimental Airplane..... just a thought.
Regards,
Troy
tscott1217@bellsouth.net
Message 12
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| Subject: | Re: personal ELT |
--> AeroElectric-List message posted by: Benford2@aol.com
In a message dated 3/5/2004 1:34:24 PM Mountain Standard Time,
tscott1217@bellsouth.net writes:
>
> Gentlemen,
>
> If I carry a personal EPIRB, do I still have to install a standard aircraft
> EPIRB? Probably so..... But I wonder if one of the little personal EPIRBs
> could be adapted for use in an Experimental Airplane..... just a thought.
>
> Regards,
> Troy
> tscott1217@bellsouth.net
>
>
The ones I have seen cost several times more then a good ELT for the plane,,
do not archive
Message 13
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| Subject: | Re: personal ELT |
--> AeroElectric-List message posted by: richard@riley.net
At 06:45 PM 3/5/04 -0500, you wrote:
>--> AeroElectric-List message posted by: Benford2@aol.com
>
>In a message dated 3/5/2004 1:34:24 PM Mountain Standard Time,
>tscott1217@bellsouth.net writes:
>
>
> >
> > Gentlemen,
> >
> > If I carry a personal EPIRB, do I still have to install a standard aircraft
> > EPIRB? Probably so..... But I wonder if one of the little personal EPIRBs
> > could be adapted for use in an Experimental Airplane..... just a thought.
> >
> > Regards,
> > Troy
> > tscott1217@bellsouth.net
> >
> >
>
>The ones I have seen cost several times more then a good ELT for the plane,,
That's probably because you're looking at 406 mhz EPIRBs, and 121.5
ELT's. 406 mhz ELT's are several thousand dollars - it's a vastly superior
technology. http://www.avweb.com/news/avionics/184338-1.html
I've been thinking of buying a 406 EPIRB with built in GPS, and tearing the
inertia switch out of an old ELT and doing the wiring myself.
Message 14
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| Subject: | Re: personal ELT |
--> AeroElectric-List message posted by: "Dan Branstrom" <danbranstrom@verizon.net>
With an EPIRB, they're going to find you a LOT faster than any ELT, and
with the registration, if it accidentally gets activated, they'll call your
home immediately. It's far superior technology, and there should be some
sort of a means of stating that it complies with the ELT requirement.
Yes, it costs more, but it works. Most of the time, false ELT signals are
what are chased down, not accidents.
Dan Branstrom.
----- Original Message -----
From: <richard@riley.net>
Subject: Re: AeroElectric-List: personal ELT
> --> AeroElectric-List message posted by: richard@riley.net
>
> At 06:45 PM 3/5/04 -0500, you wrote:
> >--> AeroElectric-List message posted by: Benford2@aol.com
> >
> >In a message dated 3/5/2004 1:34:24 PM Mountain Standard Time,
> >tscott1217@bellsouth.net writes:
> >
> >
> > >
> > > Gentlemen,
> > >
> > > If I carry a personal EPIRB, do I still have to install a standard
aircraft
> > > EPIRB? Probably so..... But I wonder if one of the little personal
EPIRBs
> > > could be adapted for use in an Experimental Airplane..... just a
thought.
> > >
> > > Regards,
> > > Troy
> > > tscott1217@bellsouth.net
> > >
> > >
> >
> >The ones I have seen cost several times more then a good ELT for the
plane,,
>
> That's probably because you're looking at 406 mhz EPIRBs, and 121.5
> ELT's. 406 mhz ELT's are several thousand dollars - it's a vastly
superior
> technology. http://www.avweb.com/news/avionics/184338-1.html
>
> I've been thinking of buying a 406 EPIRB with built in GPS, and tearing
the
> inertia switch out of an old ELT and doing the wiring myself.
>
>
Message 15
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| Subject: | Re: personal ELT |
--> AeroElectric-List message posted by: Kevin Horton <khorton01@rogers.com>
>--> AeroElectric-List message posted by: richard@riley.net
>
>At 06:45 PM 3/5/04 -0500, you wrote:
>>--> AeroElectric-List message posted by: Benford2@aol.com
>>
>>In a message dated 3/5/2004 1:34:24 PM Mountain Standard Time,
>>tscott1217@bellsouth.net writes:
>>
>>
>> >
>> > Gentlemen,
>> >
>> > If I carry a personal EPIRB, do I still have to install a
>>standard aircraft
>> > EPIRB? Probably so..... But I wonder if one of the little
>>personal EPIRBs
>> > could be adapted for use in an Experimental Airplane..... just a thought.
>> >
>> > Regards,
>> > Troy
>> > tscott1217@bellsouth.net
>> >
>> >
>>
>>The ones I have seen cost several times more then a good ELT for the plane,,
>
>That's probably because you're looking at 406 mhz EPIRBs, and 121.5
>ELT's. 406 mhz ELT's are several thousand dollars - it's a vastly superior
>technology. http://www.avweb.com/news/avionics/184338-1.html
>
>I've been thinking of buying a 406 EPIRB with built in GPS, and tearing the
>inertia switch out of an old ELT and doing the wiring myself.
If you have a US registered aircraft, then FAR 91.207 applies:
FAR 91.207: Emergency locator transmitters.
(a) Except as provided in paragraphs (e) and (f) of this section, no
person may operate a U.S.-registered civil airplane unless --
(1) There is attached to the airplane an approved automatic type
emergency locator transmitter that is in operable condition for the
following operations
"Approved" means the ELT must have a TSO. EPIRBs don't have TSOs, as
far as I can tell.
--
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://go.phpwebhosting.com/~khorton/rv8/
Message 16
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| Subject: | Re: personal ELT |
--> AeroElectric-List message posted by: richard@riley.net
>
>If you have a US registered aircraft, then FAR 91.207 applies:
>
>FAR 91.207: Emergency locator transmitters.
>
>
>(a) Except as provided in paragraphs (e) and (f) of this section, no
>person may operate a U.S.-registered civil airplane unless --
>
> (1) There is attached to the airplane an approved automatic type
>emergency locator transmitter that is in operable condition for the
>following operations
>
>"Approved" means the ELT must have a TSO. EPIRBs don't have TSOs, as
>far as I can tell.
There's legal, and there's real.
To be legal, I can use a piece of crap ELT that's been banging around my
shop for a few years. Throw a new battery in it, it's legal. And it's
almost useless in a real emergency.
So, I add to that a personal EPIRB for about $800. Now I have something
that might actually get me rescued. Nothing in the FAR's that says I
can't have an EPIRB.
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