Today's Message Index:
----------------------
1. 07:21 AM - Re: Re: Rrelay diagram for Microair PTT (Jeff Hottle)
2. 07:22 AM - Re: Re: Rrelay diagram for Microair PTT (Jeff Hottle)
3. 08:58 AM - Re: Re: Rrelay diagram for Microair PTT (Mark Phillips)
4. 10:04 AM - Re: Re: Rrelay diagram for Microair PTT (Jeff Hottle)
5. 10:48 AM - Re: Re: Relay diagram for Microair PTT (Robert L. Nuckolls, III)
6. 11:43 AM - Alternator Noise in Headset (Pete Waters)
7. 11:48 AM - Re: Re: Rrelay diagram for Microair PTT (Mark Phillips)
8. 03:39 PM - Re: Fuse Blocks, fuses, fusible links and CBs (Chris Good)
9. 04:44 PM - Switched gnd? (Larry Bowen)
10. 05:29 PM - Re: Switched gnd? (Robert L. Nuckolls, III)
11. 07:14 PM - Re: Switched gnd? (Robinson, Chad)
12. 09:01 PM - Re: Switched gnd? (Lyle Peterson)
13. 09:01 PM - Re: Re: Relay diagram for Microair PTT (Sigma Eta Aero)
14. 09:01 PM - Battery Contactor vibration problem (Vince Ackerman)
15. 09:04 PM - Re: Switched gnd? (Larry Bowen)
16. 09:11 PM - Re: Switched gnd? (Larry Bowen)
17. 09:56 PM - Re: Switched gnd? (Lyle Peterson)
18. 11:00 PM - Re: Switched gnd? (Robinson, Chad)
Message 1
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| Subject: | Re: Rrelay diagram for Microair PTT |
--> AeroElectric-List message posted by: "Jeff Hottle" <jeffh@primatech.com>
Don't lose your hair, Mark :)
Bob's drawing is good EXCEPT you need to run the red wires to the
opposite relays.
>--> AeroElectric-List message posted by: Mark Phillips <ripsteel@edge.net>
>
>Ooops- sorry, my screw-up----I meant the Pilot Mic Hi & Co-pilot Mic Hi, not Mic
Lo- from the
>drawing it appears that when the mic is keyed , which if I understand this, the
coil in the
>relay is grounded, switching the contacts from the position shown, and the respective
circuit
>from the radio to the mic will OPEN or am I that electrically challenged? 8-)
>
>Not meaning to pester, but I'm getting a bald spot from all the head-scratchin'!
>Mark do not archive
>
>> on the Mic relay circuit cited below, should not the Mic Hi & Mic
>> >Lo connections to the radio be made to the NO contacts of the relays?
>>
>> don't know why. you described the operation you wanted and I believe
>> the circuit I drew will do that. I didn't take time to noodle out
>> Microair's circuit . . . it probably does work as they intended
>> but I didn't have time to wade through their schematic and erratic
>> font displays.
<snip>
>> Bob . . .
Message 2
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| Subject: | Re: Rrelay diagram for Microair PTT |
--> AeroElectric-List message posted by: "Jeff Hottle" <jeffh@primatech.com>
Oops, that should be the BLUE wires. I didn't have my morning coffee yet.
Message 3
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| Subject: | Re: Rrelay diagram for Microair PTT |
--> AeroElectric-List message posted by: Mark Phillips <ripsteel@edge.net>
Interesting- that would also work, sharing the three functions between the two
relays (mic signal on one, PTT operate and opposite mic disable on the other).
Can you confirm that relocating the red and blue wires from the radio from the
NC contact to the adjacent NO contact would also work, using one relay for each
separate mic?
Mark - do not archive
Jeff Hottle wrote:
> --> AeroElectric-List message posted by: "Jeff Hottle" <jeffh@primatech.com>
>
> Oops, that should be the BLUE wires. I didn't have my morning coffee yet.
>
Message 4
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| Subject: | Re: Rrelay diagram for Microair PTT |
--> AeroElectric-List message posted by: "Jeff Hottle" <jeffh@primatech.com>
I believe the idea behind Bob's schematic is to disconnect the opposite
mic when one of the PTT buttons is pressed.
If you want to use the built-in intercom you need the mic signals when
you're not transmitting, so they need to be on the NC side.
A while back I drew a similar schematic using double-pole relays and a
3-position toggle for pilot only, pilot priority, or first-come
first-served.
Jeff
Mark Phillips wrote:
>Interesting- that would also work, sharing the three functions between the two
>relays (mic signal on one, PTT operate and opposite mic disable on the other).
>Can you confirm that relocating the red and blue wires from the radio from the
>NC contact to the adjacent NO contact would also work, using one relay for each
>separate mic?
>
>Mark - do not archive
Message 5
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| Subject: | Re: Relay diagram for Microair PTT |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 03:47 PM 10/5/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: Mark Phillips <ripsteel@edge.net>
>
>Ooops- sorry, my screw-up----I meant the Pilot Mic Hi & Co-pilot Mic Hi,
>not Mic Lo- from the
>drawing it appears that when the mic is keyed , which if I understand
>this, the coil in the
>relay is grounded, switching the contacts from the position shown, and the
>respective circuit
>from the radio to the mic will OPEN or am I that electrically challenged? 8-)
>
>Not meaning to pester, but I'm getting a bald spot from all the
>head-scratchin'!
>Mark do not archive
Some folks spotted an error I introduced while "prettying up" the
drawing . . . got the relay pull-down leads reversed to their
respective microphone jacks. Thank's for the sharp eyes guys!
The corrected last page for instructions can be accessed at:
http://www.aeroelectric.com/Catalog/avionics/fcfs_ptt.pdf
The whole instruction manual with corrections incorporated is
available at:
http://www.aeroelectric.com/Catalog/avionics/760imB.pdf
Bob . . .
Message 6
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| Subject: | Alternator Noise in Headset |
--> AeroElectric-List message posted by: Pete Waters <pedroagua@yahoo.com>
--0-1011535678-1065465776=:8230
Bob,
I'm starting to develop an electrical problem in my RV-4 and I'm hoping you can
help me diagnose it.
I bought the RV-4 (completed) last year. It was built in 1988 and I'm the fourth
owner. It's a solid airplane, but the documentation is thin and from the
logbooks it appears that the electrical stuff (lights, radios) were added piecemeal
over the plnae's first few years, so the electrical system is a bit tangled.
For example, my nav light circuit breaker kept popping. I finally figured
out that the builder / modifier has three 2-amp bulbs (6 amps) going through
a 5-amp CB. So I replaced the 5A CB with a 10A CB. Worked great.
However, on my next flight, I started hearing a whine in my headset. More of
a tone, actually, sounding a lot like Morse from an VOR. Originally intermittent,
and as I returned from a cross country it became almost constant. The whine
/ tone is present with the radios off, strobes off, and alternator off, although
I didn't think to pull the breakers on those circuits. I can hear it
in the background during intercom and radio reception. It disappears briefly after
a radio transmission and then returns after a few seconds. The plane has
a voltmeter, no ammeter, and I immediately noticed that the voltage was increasing
to about 15.5 V and fluctuating there for a while. Then it settled down
to 14.5 V. The problem comes and goes and is not entirely repeatable. Also,
perhaps related and perhaps not, the LORAN stopped working a few weeks back.
I had thought it had just died due to age, and I was buying a GPS anyway, so
I've just left it off since and plan to remove it.
I'm thinking the obvious thought that the alternator's going. Because the plane
has so little documentation, I don't know the specifics of the alternator
at all or how old it is, just that it's been working so far. My A&P found nothing
wrong with it at the last annual 60 hours ago. I'm wondering if the impending
alternator failure is putting out RF that's getting into the headset and
was jamming the LORAN.
Also, I've noticed that with the electrical system fully loaded up, the voltmeter
needle also starts rapidly fluctuating at 14.5-15.5V. I see this when I
turn on the landing light. Due to the lack of documentation I have no idea how
many total amps are actually flowing through the system, so I'm wondering if
turning on the landing lights actually puts the plane's total current draw above
the rated output of the alternator. Is fluctuating system voltage a sign
of that?
If you could offer any thoughts on this, I'd appreciate it.
Best,
Pete Waters
(registered for your class in Watsonville)
---------------------------------
--0-1011535678-1065465776=:8230
<DIV>Bob,</DIV>
<DIV> </DIV>
<DIV> I'm starting to develop an electrical problem in my RV-4 and I'm hoping
you can help me diagnose it.</DIV>
<DIV> I bought the RV-4 (completed) last year. It was built in 1988
and I'm the fourth owner. It's a solid airplane, but the documentation is thin
and from the logbooks it appears that the electrical stuff (lights, radios)
were added piecemeal over the plnae's first few years, so the electrical system
is a bit tangled. For example, my nav light circuit breaker kept popping.
I finally figured out that the builder / modifier has three 2-amp bulbs
(6 amps) going through a 5-amp CB. So I replaced the 5A CB with a 10A
CB. Worked great. </DIV>
<DIV> However, on my next flight, I started hearing a whine in my headset.
More of a tone, actually, sounding a lot like Morse from an VOR.
Originally intermittent, and as I returned from a cross country it became almost
constant. The whine / tone is present with the radios off, strobes off,
and alternator off, although I didn't think to pull the breakers on those
circuits. I can hear it in the background during intercom and radio reception. It
disappears briefly after a radio transmission and then returns
after a few seconds. The plane has a voltmeter, no ammeter, and I immediately
noticed that the voltage was increasing to about 15.5 V and fluctuating
there for a while. Then it settled down to 14.5 V. The problem comes
and goes and is not entirely repeatable. Also, perhaps related and perhaps
not, the LORAN stopped working a few weeks back. I had thought it
had just died due to age, and I was buying a GPS anyw
ay, so
I've just left it off since and plan to remove it.</DIV>
<DIV> I'm thinking the obvious thought that the alternator's going.
Because the plane has so little documentation, I don't know the specifics of
the alternator at all or how old it is, just that it's been working so far.
My A&P found nothing wrong with it at the last annual 60 hours ago.
I'm wondering if the impending alternator failure is putting out RF that's
getting into the headset and was jamming the LORAN.</DIV>
<DIV> Also, I've noticed that with the electrical system fully loaded up,
the voltmeter needle also starts rapidly fluctuating at 14.5-15.5V. I
see this when I turn on the landing light. Due to the lack of documentation
I have no idea how many total amps are actually flowing through the system, so
I'm wondering if turning on the landing lights actually puts the
plane's total current draw above the rated output of the alternator.
Is fluctuating system voltage a sign of that?</DIV>
<DIV> If you could offer any thoughts on this, I'd appreciate it.</DIV>
<DIV> </DIV>
<DIV>Best,</DIV>
<DIV>Pete Waters</DIV>
<DIV>(registered for your class in Watsonville)</DIV><p><hr SIZE=1>
--0-1011535678-1065465776=:8230--
Message 7
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| Subject: | Re: Rrelay diagram for Microair PTT |
--> AeroElectric-List message posted by: Mark Phillips <ripsteel@edge.net>
ah HA! Intercom function! Now I see it- thanks!
Mark do not archive
Jeff Hottle wrote:
> --> AeroElectric-List message posted by: "Jeff Hottle" <jeffh@primatech.com>
>
> I believe the idea behind Bob's schematic is to disconnect the opposite
> mic when one of the PTT buttons is pressed.
>
> If you want to use the built-in intercom you need the mic signals when
> you're not transmitting, so they need to be on the NC side.
>
> A while back I drew a similar schematic using double-pole relays and a
> 3-position toggle for pilot only, pilot priority, or first-come
> first-served.
>
> Jeff
>
> Mark Phillips wrote:
>
> >Interesting- that would also work, sharing the three functions between the two
> >relays (mic signal on one, PTT operate and opposite mic disable on the other).
> >Can you confirm that relocating the red and blue wires from the radio from the
> >NC contact to the adjacent NO contact would also work, using one relay for each
> >separate mic?
> >
> >Mark - do not archive
>
Message 8
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| Subject: | Re: Fuse Blocks, fuses, fusible links and CBs |
--> AeroElectric-List message posted by: "Chris Good" <chrisjgood@lycos.com>
Greg,
As far as the flap motor goes, I've got a note that it takes 5 amps, although I
don't remember where I found that. In any case, I used 16 awg wire & a 10 amp
fuse. It's operated perfectly for 600 hrs with no nuisance fuse trips.
Regards,
Chris Good, http://rv.supermatrix.com
West Bend, WI
RV-6A 86CG, flying 600 hrs
BTW, I'm expecting to be in Honolulu for Thanksgiving. Maybe I'll get a chance
to see your project.
--
--------- Original Message ---------
DATE: Fri, 3 Oct 2003 18:24:59
From: Greg Grigson <iflyhawaii2@yahoo.com>
>--> AeroElectric-List message posted by: Greg Grigson <iflyhawaii2@yahoo.com>
>
>--0-361577249-1065230699=:58092
>
>Bob,
> I am using a derivative of Figure Z-11 architecture for an RV6. I want to feed
the electronic ignition from a hot battery bus. The LSE installation instructions
say to use a "pullable" 5 amp breaker. The Aeroelectric connection mentions
use of a fusible link in this application. I would much prefer a fusible
link with an on/off switch over a CB. Do these electronic ignition systems
nuisance trip in general? I thought they were supposed to be incredibly reliable
(That's why I bought it!!).
>
> What would you suggest for a feed to the flap motor. I thought I read something
about this is one particular animal that can nuisance trip. If you were
to recommend a CB application how would you power that off say the main bus/fuse
block? I would prefer to keep the ALT FLD CB the only breaker on the panel,
if practical.
>
> I haven't seen listed the expected current draw for the flap motor. Can anybody
help me out here?
>
>Thanks.
>Greg Grigson
>Honolulu
>
>
Message 9
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--> AeroElectric-List message posted by: "Larry Bowen" <Larry@bowenaero.com>
The rule of thumb seems to be to switch the positive line rather than
the negative/ground for a typical circut. I have the need to break this
rule and wire my fuel pump positve with no switch and switch the ground
to turn it on/off. Is this a huge no-no? Bad style? No big deal? Why
does it matter?
Thanks,
-
Larry Bowen
Larry@BowenAero.com
http://BowenAero.com
Message 10
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| Subject: | Re: Switched gnd? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 07:45 PM 10/6/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "Larry Bowen" <Larry@bowenaero.com>
>
>The rule of thumb seems to be to switch the positive line rather than
>the negative/ground for a typical circut. I have the need to break this
>rule and wire my fuel pump positve with no switch and switch the ground
>to turn it on/off. Is this a huge no-no? Bad style? No big deal? Why
>does it matter?
>
>Thanks,
It doesn't. Control circuitry aboard aircraft are done
both ways. I'm unaware of any such rule-of-thumb . . .
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
Message 11
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--> AeroElectric-List message posted by: "Robinson, Chad" <crobinson@rfgonline.com>
> The rule of thumb seems to be to switch the positive line rather than
> the negative/ground for a typical circut. I have the need to break this
> rule and wire my fuel pump positve with no switch and switch the ground
> to turn it on/off. Is this a huge no-no? Bad style? No big deal? Why
> does it matter?
This sounds like more of an issue in high voltage AC electrical wiring such as
you have in your home. There you want to switch the "hot" side so that when the
switch is off, there is mains voltage reaching the device/circuit. Otherwise,
if the device (say, a lamp) was on, the white (neutral/return) wire would be
hot, which can create a dangerous situation for anybody mucking with the wires.
It's a safety issue, with lots of ramifications for both electricians and product
designers.
But for a 12V circuit? My car has several circuits wired this way. I can't see
why it would be a problem in a plane. Maybe Bob has some guidance here?
Regards,
Chad
Message 12
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--> AeroElectric-List message posted by: "Lyle Peterson" <lyleap@access4less.net>
I for one would want to switch the positive side of the circuit. If the
device being controlled by the switch failed in a shorted mode, there
would still be positive voltage to it. The switch would not save the
device as it is grounded to the frame of the vehicle, airplane. In a
composite airframe this may not be a concern. In a metal airplane I
would definitely not switch the negative side of the circuit.
My milli pennies worth.
Gee, opinions are depreciating rather rapidly, aren't they?
Lyle
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Robinson, Chad
Subject: RE: AeroElectric-List: Switched gnd?
--> AeroElectric-List message posted by: "Robinson, Chad"
--> <crobinson@rfgonline.com>
> The rule of thumb seems to be to switch the positive line rather than
> the negative/ground for a typical circut. I have the need to break
> this rule and wire my fuel pump positve with no switch and switch the
> ground to turn it on/off. Is this a huge no-no? Bad style? No big
> deal? Why does it matter?
This sounds like more of an issue in high voltage AC electrical wiring
such as you have in your home. There you want to switch the "hot" side
so that when the switch is off, there is mains voltage reaching the
device/circuit. Otherwise, if the device (say, a lamp) was on, the white
(neutral/return) wire would be hot, which can create a dangerous
situation for anybody mucking with the wires. It's a safety issue, with
lots of ramifications for both electricians and product designers.
But for a 12V circuit? My car has several circuits wired this way. I
can't see why it would be a problem in a plane. Maybe Bob has some
guidance here?
Regards,
Chad
==
direct advertising on the Matronics Forums.
==
http://www.matronics.com/trouble-report
==
==
Message 13
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| Subject: | Re: Relay diagram for Microair PTT |
--> AeroElectric-List message posted by: Sigma Eta Aero <sigmatero@yahoo.com>
--0-1904218001-1065499228=:60162
Good stuff, thanks Bob. Now if you'll hold my hand just a minute longer and suggest
the "perfect" DigiKey diodes to go with both the OV disconnect relay and
these relays I would be grateful. The pic on your site shows a 1N4005 but there
are about a dozen of these that show up in the DigiKey website.
Also, where are the red and white connectors that come with the B&C OV module kit
best used?
Joa
---------------------------------
--0-1904218001-1065499228=:60162
<DIV>Good stuff, thanks Bob. Now if you'll hold my hand just a minute longer
and suggest the "perfect" DigiKey diodes to go with both the OV disconnect
relay and these relays I would be grateful. The pic on your site shows
a 1N4005 but there are about a dozen of these that show up in the DigiKey website.
</DIV>
<DIV> </DIV>
<DIV>Also, where are the red and white connectors that come with the B&C OV
module kit best used?</DIV>
<DIV> </DIV>
<DIV>Joa</DIV><p><hr SIZE=1>
--0-1904218001-1065499228=:60162--
Message 14
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| Subject: | Battery Contactor vibration problem |
--> AeroElectric-List message posted by: Vince Ackerman <vack@mac.com>
I installed a battery master switch with contactor (one or the 3
terminal ones sold by Aircraft Spruce) on my Rotorway 162f project. For
reasons of space I installed it upside down. While testing out the
electrical system I noticed that tapping with a small rubber mallet on
the bracket that it's mounted to will cause it to interrupt the power
momentarily. It doesn't matter if I tap from top or bottom, it seems
to disconnect for a split second. I know it's disconnecting because my
rotor tach goes through it's initialization test on first power up, and
it's doing that every time. Also, other indicator lights flicker, so
it's not just the tach, nor loose battery leads, etc.
You can understand my hesitation about using this since it's a helo
(they aren't the smoothest) with two FADEC's that can't be electrically
interrupted. Are there any stronger or more reliable contactors,
perhaps even solid state? Any suggestions for how to fix this?
Thanks
Vince Ackerman
N777FB
Message 15
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--> AeroElectric-List message posted by: "Larry Bowen" <Larry@bowenaero.com>
That's good news. I guess I just developed that impression during my
miniscule electrical experience. I know some light-weight circuits
switch the ground, i.e. for enunciator lights, etc -- but I thought
bigger 'appliances' had to have the + switched. Glad to hear that's not
always the case. Thanks.
-
Larry Bowen
Larry@BowenAero.com
http://BowenAero.com
> -----Original Message-----
> From: Robert L. Nuckolls, III [mailto:bob.nuckolls@cox.net]
> Sent: Monday, October 06, 2003 8:29 PM
> To: aeroelectric-list@matronics.com
> Subject: Re: AeroElectric-List: Switched gnd?
>
>
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> --> <bob.nuckolls@cox.net>
>
> At 07:45 PM 10/6/2003 -0400, you wrote:
> >--> AeroElectric-List message posted by: "Larry Bowen"
> >--> <Larry@bowenaero.com>
> >
> >The rule of thumb seems to be to switch the positive line
> rather than
> >the negative/ground for a typical circut. I have the need to break
> >this rule and wire my fuel pump positve with no switch and
> switch the
> >ground to turn it on/off. Is this a huge no-no? Bad style? No big
> >deal? Why does it matter?
> >
> >Thanks,
>
> It doesn't. Control circuitry aboard aircraft are done
> both ways. I'm unaware of any such rule-of-thumb . . .
>
> Bob . . .
>
> --------------------------------------------
> ( Knowing about a thing is different than )
> ( understanding it. One can know a lot )
> ( and still understand nothing. )
> ( C.F. Kettering )
> --------------------------------------------
Message 16
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--> AeroElectric-List message posted by: "Larry Bowen" <Larry@bowenaero.com>
The fuse/breaker would provide protection. Would it not?
-
Larry Bowen
Larry@BowenAero.com
http://BowenAero.com
> -----Original Message-----
> From: Lyle Peterson [mailto:lyleap@access4less.net]
> Sent: Tuesday, October 07, 2003 12:01 AM
> To: aeroelectric-list@matronics.com
> Subject: RE: AeroElectric-List: Switched gnd?
>
>
> --> AeroElectric-List message posted by: "Lyle Peterson"
> --> <lyleap@access4less.net>
>
> I for one would want to switch the positive side of the
> circuit. If the device being controlled by the switch failed
> in a shorted mode, there would still be positive voltage to
> it. The switch would not save the device as it is grounded
> to the frame of the vehicle, airplane. In a composite
> airframe this may not be a concern. In a metal airplane I
> would definitely not switch the negative side of the circuit.
>
> My milli pennies worth.
>
> Gee, opinions are depreciating rather rapidly, aren't they?
>
> Lyle
>
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com] On
> Behalf Of Robinson, Chad
> To: aeroelectric-list@matronics.com
> Subject: RE: AeroElectric-List: Switched gnd?
>
>
> --> AeroElectric-List message posted by: "Robinson, Chad"
> --> <crobinson@rfgonline.com>
>
> > The rule of thumb seems to be to switch the positive line
> rather than
> > the negative/ground for a typical circut. I have the need to break
> > this rule and wire my fuel pump positve with no switch and
> switch the
> > ground to turn it on/off. Is this a huge no-no? Bad
> style? No big
> > deal? Why does it matter?
>
> This sounds like more of an issue in high voltage AC
> electrical wiring such as you have in your home. There you
> want to switch the "hot" side so that when the switch is off,
> there is mains voltage reaching the device/circuit.
> Otherwise, if the device (say, a lamp) was on, the white
> (neutral/return) wire would be hot, which can create a
> dangerous situation for anybody mucking with the wires. It's
> a safety issue, with lots of ramifications for both
> electricians and product designers.
>
> But for a 12V circuit? My car has several circuits wired this
> way. I can't see why it would be a problem in a plane. Maybe
> Bob has some guidance here?
>
> Regards,
> Chad
>
>
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Message 17
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--> AeroElectric-List message posted by: "Lyle Peterson" <lyleap@access4less.net>
Depends on which side is fused or breakered (is that a word?) If the
postive side is fused it would protect it. If the problem is one of
wiring the switch only to the negative side for some reason, I am
guessing that the same reasons apply to the fuse or breaker. That means
the fuse would be in the negative side and little or no protection.
Another 2 mils worth of opinion.
Lyle
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Larry
Bowen
Subject: RE: AeroElectric-List: Switched gnd?
--> AeroElectric-List message posted by: "Larry Bowen"
--> <Larry@bowenaero.com>
The fuse/breaker would provide protection. Would it not?
-
Larry Bowen
Larry@BowenAero.com
http://BowenAero.com
Message 18
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--> AeroElectric-List message posted by: "Robinson, Chad" <crobinson@rfgonline.com>
> > Larry Bowen wrote:
> >
> > The fuse/breaker would provide protection. Would it not?
>
> Lyle Peterson wrote:
>
> Depends on which side is fused or breakered (is that a word?) If the
> postive side is fused it would protect it. If the problem is one of
> wiring the switch only to the negative side for some reason, I am
> guessing that the same reasons apply to the fuse or breaker.
> That means the fuse would be in the negative side and little or no
> protection.
On the other hand, one would probably not be wiring a negative-switched device
into one's standard fuse panel, that being a 12V source itself. So Larry, unless
you're looking to create a separate fuse panel of all NEGATIVE switched devices,
I assumed you meant that you'd have an inline fuse or breaker upstream of
this negative-switched device (that is, on the supply side). Is this the case?
Because Lyle is right - wherever you put the switch, the FUSE should be on
the supply side no matter what. And if your breaker IS your switch, then this
is not a great idea.
However, I'd like to restate my point that switch/breaker location is a bigger
issue in systems where the voltage is not so fun to touch - a human can die from
mains voltage without ever tripping a standard 20A breaker. Therefore, you
always want a way to cut off the supply side as close to the source as possible,
and so the breaker is ALWAYS on the hot side.
My $0.00002c. =)
Regards,
Chad
PS - None of my dictionaries (all relatively new, FWIW) contain "breakered" as
an acceptable form of "breaker". However, LOTS of electrical supply and products
companies like to use it, so I say what the heck, if the people you're talking
to understand what you mean...
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