Today's Message Index:
----------------------
1. 06:16 AM - Re: Relay Question: Adding control relay to SD-8 circuit (user9253)
2. 07:37 AM - Re: Relay Question: Adding control relay to SD-8 circuit (Airdog77)
3. 11:06 AM - Re: Relay Question: Adding control relay to SD-8 circuit (user9253)
4. 11:45 AM - Re: Relay Question: Adding control relay to SD-8 circuit (Airdog77)
5. 01:35 PM - Re: Re: Relay Question: Adding control relay to SD-8 circuit (Charlie England)
6. 02:46 PM - Re: Relay Question: Adding control relay to SD-8 circuit (user9253)
7. 02:47 PM - Re: Relay Question: Adding control relay to SD-8 circuit (Airdog77)
8. 03:02 PM - Re: Relay Question: Adding control relay to SD-8 circuit (Airdog77)
9. 05:50 PM - First Flight!!! (William Hunter)
10. 07:57 PM - Re: First Flight!!! (Bob Verwey)
11. 08:42 PM - Re: First Flight!!! (William Hunter)
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Subject: | Re: Relay Question: Adding control relay to SD-8 circuit |
A picture is worth a thousands words. Now I understand your proposed circuit.
There are two problems with it. First, the two relay coils are in series with
each other. Each relay coil will only have about 6 or 7 volts dropped across
it, not enough to reliably pull it in, if they work at all. The second problem
is that if one relay coil fails, so will the other one. It reminds me of
a string of Christmas lights, one bulb burns out and they all go out.
If there is a source of power available in the nose of the aircraft, a transistor
circuit will work by monitoring the voltage at the aux-alt circuit breaker.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=477806#477806
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Subject: | Re: Relay Question: Adding control relay to SD-8 circuit |
Joe,
It actually does work on the bench, but I realized I was putting these relays in
series and it's not something I had seen as a normal practice. Even though it
worked something didn't seem right about it, thus my wanting a crosscheck. Thanks
for providing one!
I do have a battery buss at the front were I could pull power from... so if I read
your right, I'm looking at pulling power off the 2A CB to then drive a transistor
to provide me the subsequent control to open the circuit.
Regards,
Wade
--------
Airdog
Wade Parton
Building Long-EZ N916WP
www.longezpush.com
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=477811#477811
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Subject: | Re: Relay Question: Adding control relay to SD-8 circuit |
A MOSFET transistor can monitor input voltage without actually drawing any current.
Exactly where the transistor input is connected depends on what you want
to monitor, relay or switch. They might have different voltages depending on
coil failure or CB tripping. If you describe the intended load and under what
conditions it should be turned on or off, someone on this list can design a
transistor circuit.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=477820#477820
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Subject: | Re: Relay Question: Adding control relay to SD-8 circuit |
Joe,
> If you describe the intended load and under what conditions it should be turned
on or off
It's a 2.5A charging lead for a backup battery system that I don't want to draw
off the E-Bus in a scenario where my main alternator goes down and I'm on SD-8/E-Bus
only power. The condition is simply if the SD-8 is turned on for use
as the primary alternator --again, in a scenario where the main alternator is
taken offline-- then I would like this to be an automatic ancillary function of
the SD-8 being brought online (the opposite holds true as well: SD-8 OFF, then
the charging circuit is reestablished).
In my attempt to integrate this after all the cables are run through bulkheads,
etc. my optimal access to this charging lead is in the nose, with my SD-8 in
the aft section of the aircraft (Long-EZ/pusher).
Much thanks!
Regards,
Wade
--------
Airdog
Wade Parton
Building Long-EZ N916WP
www.longezpush.com
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=477821#477821
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Subject: | Re: Relay Question: Adding control relay to SD-8 |
circuit
On 2/4/2018 1:45 PM, Airdog77 wrote:
>
> Joe,
>
>
>> If you describe the intended load and under what conditions it should be turned
on or off
>
> It's a 2.5A charging lead for a backup battery system that I don't want to draw
off the E-Bus in a scenario where my main alternator goes down and I'm on SD-8/E-Bus
only power. The condition is simply if the SD-8 is turned on for use
as the primary alternator --again, in a scenario where the main alternator is
taken offline-- then I would like this to be an automatic ancillary function
of the SD-8 being brought online (the opposite holds true as well: SD-8 OFF,
then the charging circuit is reestablished).
>
> In my attempt to integrate this after all the cables are run through bulkheads,
etc. my optimal access to this charging lead is in the nose, with my SD-8 in
the aft section of the aircraft (Long-EZ/pusher).
>
> Much thanks!
>
> Regards,
> Wade
>
> --------
> Airdog
> Wade Parton
> Building Long-EZ N916WP
> www.longezpush.com
What's it going to power? If it powers the same stuff as the main
battery, simply upsizing the main battery might make more sense.
On the other hand, if it's in good condition it will be almost totally
topped off (fully charged) within minutes after engine start, so it
won't be sucking on the backup alternator at all.
If you're holding it in reserve in case of SD-8 failure *and* main
battery failure, why not use a fat Schottky diode to isolate it from
discharge? Schottky diodes are now cheap & widely available. (But double
failures in one flight might be less of a concern than airframe
structural failure...)
Charlie
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Subject: | Re: Relay Question: Adding control relay to SD-8 circuit |
The backup battery should have its own disconnect switch that you can turn off
manually if need be. I do not think that it is necessary to disconnect the backup
battery if and when the main alternator fails. Assuming that the backup
battery is charged before takeoff, then it is not going to be much of a load on
the electrical system. If the main alternator fails and aux alternator has
trouble maintaining system voltage, then the main battery and backup battery can
supply part of the load. Most modern EFIS have their own backup battery.
Is another backup battery really necessary? What does ceengland7 think?
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=477826#477826
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Subject: | Re: Relay Question: Adding control relay to SD-8 circuit |
Charlie,
> On the other hand, if it's in good condition it will be almost totally
> topped off (fully charged) within minutes after engine start, so it
> won't be sucking on the backup alternator at all.
Yes, this is correct.
> If you're holding it in reserve in case of SD-8 failure *and* main
> battery failure, why not use a fat Schottky diode to isolate it from
> discharge? Schottky diodes are now cheap & widely available. (But double
> failures in one flight might be less of a concern than airframe
> structural failure...)
It's not really about a totally battery failure. Yes, I do have panel items with
power inputs on the battery backup system as a tertiary backup in case of the
total doomsday scenario... then I have about 45 min worth of use on those components.
But my bigger concern is in the event of JUST a main alternator failure,
and I go to SD-8 alternator power only. I simply want to ensure that at
no time does the backup battery system decide it wants to starting charging
at 2.5 amps sucking up on/about 25-50% of my SD-8 output (depending on my engine
RPM).
I understand the likelihood of this event is low, but if it's simple and doable
enough I'd like to add in this circuit now (i.e. while the weather is COLD) before
I move on to more pressing aircraft build matters.
I'll definitely look at using a Schottky as well. Thanks!
Regards,
Wade
--------
Airdog
Wade Parton
Building Long-EZ N916WP
www.longezpush.com
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=477827#477827
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Subject: | Re: Relay Question: Adding control relay to SD-8 circuit |
Joe,
Finally found that extra DPDT switch I swore I had on hand and made some slight
(yet painful) adjustments to fit that sucker in.
I'll simple go with an extra wire and add this as a checklist item.
Issue resolved!
Thanks for all the help,
Wade
--------
Airdog
Wade Parton
Building Long-EZ N916WP
www.longezpush.com
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=477828#477828
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Hey everybody, I did my first flight today!
Thanks everybody for all of your patience and question-answering you've
helped me with over the last couple years! To clamp the headset onto your
head, strap your airplane to your butt, turn on the avionics and see all of
these fancy colors and the little cute girl who talks to you is really
cool! Major dopamine rush!!!
No smoke was let out of the wires so I was pretty happy. A couple of
avionics tuning issues but so far most of the stuff is working good...
except.. one little thing
I have an SD- 20 alternator that is controlled by a LR3C-14 voltage
regulator. It had been working perfectly for numerous ground engine
run-ups idling Etc and then all of a sudden during the first flight it
stopped producing power.
Naturally I checked the voltage regulator sense and field circuit breakers
and they were not popped but I did pull and reset them however that did not
fix the problem.
Since I have two Independent Electrical systems I tied the two buses and
pressed on for my 1 hour and 35 minute flight.
Back on the ground I thought that since both systems are controlled by the
LR3C-14 voltage regulator I swapped the voltage regulator from the good
side to the offending side and the SD-20 alternator started producing power
again.
Since the other electrical system voltage regulator was not wired up (it
was being used to control the little SD-20) I tied the bus and loaded up
the electrical system and the little alternator produced 17 amps.
So I assumed it was the voltage regulator that was bad.
I then rewired up both systems as they are supposed to be wired up and
started the engine again and both voltage regulators are working fine...
Is there some kind of a reason why the little alternator would decide to
stop producing?
It never produced more than about 8 amps the whole flight so it's doubtful
it was overloaded.
During flight my safety scheme is to keep the two busses isolated and since
the bust I was open I could tell that the ampere reading on that side was
low and the voltage on that bus also began to drop so it was not just the
indicator that was the problem.
Any advice???
Thanks,
Bill Hunter
Message 10
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Subject: | Re: First Flight!!! |
Welcome to the exclusive club, Bill!
On 05 Feb 2018 4:08 AM, "William Hunter" <billhuntersemail@gmail.com> wrote:
> Hey everybody, I did my first flight today!
>
> Thanks everybody for all of your patience and question-answering you've
> helped me with over the last couple years! To clamp the headset onto your
> head, strap your airplane to your butt, turn on the avionics and see all of
> these fancy colors and the little cute girl who talks to you is really
> cool! Major dopamine rush!!!
>
> No smoke was let out of the wires so I was pretty happy. A couple of
> avionics tuning issues but so far most of the stuff is working good...
> except.. one little thing
>
> I have an SD- 20 alternator that is controlled by a LR3C-14 voltage
> regulator. It had been working perfectly for numerous ground engine
> run-ups idling Etc and then all of a sudden during the first flight it
> stopped producing power.
>
> Naturally I checked the voltage regulator sense and field circuit breakers
> and they were not popped but I did pull and reset them however that did not
> fix the problem.
>
> Since I have two Independent Electrical systems I tied the two buses and
> pressed on for my 1 hour and 35 minute flight.
>
> Back on the ground I thought that since both systems are controlled by the
> LR3C-14 voltage regulator I swapped the voltage regulator from the good
> side to the offending side and the SD-20 alternator started producing power
> again.
>
> Since the other electrical system voltage regulator was not wired up (it
> was being used to control the little SD-20) I tied the bus and loaded up
> the electrical system and the little alternator produced 17 amps.
>
> So I assumed it was the voltage regulator that was bad.
>
> I then rewired up both systems as they are supposed to be wired up and
> started the engine again and both voltage regulators are working fine...
>
> Is there some kind of a reason why the little alternator would decide to
> stop producing?
>
> It never produced more than about 8 amps the whole flight so it's doubtful
> it was overloaded.
>
> During flight my safety scheme is to keep the two busses isolated and
> since the bust I was open I could tell that the ampere reading on that side
> was low and the voltage on that bus also began to drop so it was not just
> the indicator that was the problem.
>
> Any advice???
>
> Thanks,
>
> Bill Hunter
>
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Subject: | Re: First Flight!!! |
Actually... I should have written the subject line as "First
Re-Flight"...spell check took over...
This was a flying airplane that I completely tore apart and rebuilt so I am
not completely in that "exclusive club" ... more like the "excusive club"
But hey... it is still an accomplishment that I am happy about... if this
SD-20 will put out some juice... reliably.
Thanks,
Bill Hunter
On Feb 4, 2018 8:01 PM, "Bob Verwey" <bob.verwey@gmail.com> wrote:
> Welcome to the exclusive club, Bill!
>
> On 05 Feb 2018 4:08 AM, "William Hunter" <billhuntersemail@gmail.com>
> wrote:
>
>> Hey everybody, I did my first flight today!
>>
>> Thanks everybody for all of your patience and question-answering you've
>> helped me with over the last couple years! To clamp the headset onto your
>> head, strap your airplane to your butt, turn on the avionics and see all of
>> these fancy colors and the little cute girl who talks to you is really
>> cool! Major dopamine rush!!!
>>
>> No smoke was let out of the wires so I was pretty happy. A couple of
>> avionics tuning issues but so far most of the stuff is working good...
>> except.. one little thing
>>
>> I have an SD- 20 alternator that is controlled by a LR3C-14 voltage
>> regulator. It had been working perfectly for numerous ground engine
>> run-ups idling Etc and then all of a sudden during the first flight it
>> stopped producing power.
>>
>> Naturally I checked the voltage regulator sense and field circuit
>> breakers and they were not popped but I did pull and reset them however
>> that did not fix the problem.
>>
>> Since I have two Independent Electrical systems I tied the two buses and
>> pressed on for my 1 hour and 35 minute flight.
>>
>> Back on the ground I thought that since both systems are controlled by
>> the LR3C-14 voltage regulator I swapped the voltage regulator from the good
>> side to the offending side and the SD-20 alternator started producing power
>> again.
>>
>> Since the other electrical system voltage regulator was not wired up (it
>> was being used to control the little SD-20) I tied the bus and loaded up
>> the electrical system and the little alternator produced 17 amps.
>>
>> So I assumed it was the voltage regulator that was bad.
>>
>> I then rewired up both systems as they are supposed to be wired up and
>> started the engine again and both voltage regulators are working fine...
>>
>> Is there some kind of a reason why the little alternator would decide to
>> stop producing?
>>
>> It never produced more than about 8 amps the whole flight so it's
>> doubtful it was overloaded.
>>
>> During flight my safety scheme is to keep the two busses isolated and
>> since the bust I was open I could tell that the ampere reading on that side
>> was low and the voltage on that bus also began to drop so it was not just
>> the indicator that was the problem.
>>
>> Any advice???
>>
>> Thanks,
>>
>> Bill Hunter
>>
>
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