Today's Message Index:
----------------------
1. 02:08 AM - Inductive Spike from Starter Solenoid (John Totten)
2. 05:26 AM - Re: ON hold current for Bosch ice-cube relays ()
3. 06:08 AM - Re: Switch Question (Robert L. Nuckolls, III)
4. 06:14 AM - Re: Inductive Spike from Starter Solenoid (Robert L. Nuckolls, III)
5. 07:06 AM - Re: Switch Question (Hinde, Frank George (Corvallis))
6. 09:56 AM - Re: Switch Question (Ed Holyoke)
7. 10:09 AM - Re: Switch Question (Dr. Peter Laurence)
8. 10:24 AM - Re: Wire sizing. (Bill Dube)
9. 11:13 AM - Re: Switch Question (Ed Holyoke)
Message 1
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| Subject: | Inductive Spike from Starter Solenoid |
--> AeroElectric-List message posted by: John Totten <john@totten.com>
If anyone has a Cessna 185 alternator that goes off line
when the start the engine or retract the (amphib) gear -
then here is why. Your plane does not comply with ACS
SB92-01 and Cessna SEB91-5R1
http://www.caa.is/datadir/bsdata/img/adnotes/93-05-06.pdf
The parts needed to comply are available here
http://www.aircraftspruce.com/pdf/catalog/Cat06413.pdf
The $7 diode abolishes the starter solenoid inductive spike
and starter switch arching that trips the overvoltage relay
in the regulator. Most people that face this problem
misinterpret the problem as 'Load Dump' cause by drop in
the bus voltage from high starter loads. Not so. Disconnect
the starter and operate the solenoid alone - same problem.
The entire plane from the pilot seat forward is supplied
from the firewall solenoid positive terminal so the
solenoids inductive spike goes throughout the plane
including the panel and the regulator. It burns out not
only your avionics (if you don't have an avionics master
switch) but also the contacts in your starter switch so you
can't ground the mags. Thats why your mag check doesn't
drop the rpm - Not good.
The fix is a $7 dollar diode. Of the three C185's that I
have inspected besides mine - none comply with this SEB.
I also put the diode across the solenoid on my hydraulic
pump for the Amphib Floats which also threw the alternator
off line when the gear operated. So thats not a 'Load Dump'
problem either, its an inductive spike.
Call ACS at 602 855 8613. Save yourself the cost of that new
regulator, alternator, battery and huge mechanic bills for
a non-fix..
JohnT
Message 2
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| Subject: | Re: ON hold current for Bosch ice-cube relays |
--> AeroElectric-List message posted by: <gmcjetpilot@yahoo.com>
I got 140ma/ 85+/- 5 ohms
http://www.chiefent.com/products/product_details.asp?id=4
George
---------------------------------
Message 3
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| Subject: | Re: Switch Question |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 09:07 PM 2/7/2006 -0800, you wrote:
>--> AeroElectric-List message posted by: "Ed Holyoke" <bicyclop@pacbell.net>
>
>Howdy,
>
>I wish to use two switches to control two batteries as follows:
>I want the bottom position to be off.
>I want the center position to be battery contactor on and alternator
>field on.
>I want the top position to be e-bus alternate feed on and alternator
>field off.
>
>Is this doable? What kind of switch do I need. How would I wire it?
Would you leave the battery contactor closed while the e-bus
alternate feed is closed? Are you sure you want a single device
to have this much control over your system's functionality.
It becomes a single point of failure for lots of stuff. There's
a reason why those functions are separated out into two switches
in the Z-figures.
Bob . . .
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
Message 4
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| Subject: | Re: Inductive Spike from Starter Solenoid |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
For additional background on this phenonmenon see
http://www.aeroelectric.com/articles/spikecatcher.pdf
Bob . . .
At 01:02 AM 2/8/2006 -0900, you wrote:
>--> AeroElectric-List message posted by: John Totten <john@totten.com>
>
>
>If anyone has a Cessna 185 alternator that goes off line
>when the start the engine or retract the (amphib) gear -
>then here is why. Your plane does not comply with ACS
>SB92-01 and Cessna SEB91-5R1
>
>http://www.caa.is/datadir/bsdata/img/adnotes/93-05-06.pdf
>
>The parts needed to comply are available here
>
>http://www.aircraftspruce.com/pdf/catalog/Cat06413.pdf
>
>The $7 diode abolishes the starter solenoid inductive spike
>and starter switch arching that trips the overvoltage relay
>in the regulator. Most people that face this problem
>misinterpret the problem as 'Load Dump' cause by drop in
>the bus voltage from high starter loads. Not so. Disconnect
>the starter and operate the solenoid alone - same problem.
>
>The entire plane from the pilot seat forward is supplied
>from the firewall solenoid positive terminal so the
>solenoids inductive spike goes throughout the plane
>including the panel and the regulator. It burns out not
>only your avionics (if you don't have an avionics master
>switch) but also the contacts in your starter switch so you
>can't ground the mags. Thats why your mag check doesn't
>drop the rpm - Not good.
>
>The fix is a $7 dollar diode. Of the three C185's that I
>have inspected besides mine - none comply with this SEB.
>
>I also put the diode across the solenoid on my hydraulic
>pump for the Amphib Floats which also threw the alternator
>off line when the gear operated. So thats not a 'Load Dump'
>problem either, its an inductive spike.
>
>Call ACS at 602 855 8613. Save yourself the cost of that new
>regulator, alternator, battery and huge mechanic bills for
>a non-fix..
>
>JohnT
>
>
>--
>
>
Bob . . .
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
Message 5
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--> AeroElectric-List message posted by: "Hinde, Frank George (Corvallis)" <frank.hinde@hp.com>
The only note of caution I would add is that you have a pretty big
single point of failure in that one switch...If the switch fails (and
they do) what happens to your ability to fly the airplane.
In my current single alt, two battery airplane I have no single
component common to both electrical systems...Except for the diode that
seperates the two...Each battery system then runs one fuel pump and one
electronic igniton.
Frank
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Ed
Holyoke
Sent: Tuesday, February 07, 2006 9:08 PM
Subject: AeroElectric-List: Switch Question
--> AeroElectric-List message posted by: "Ed Holyoke"
--> <bicyclop@pacbell.net>
Howdy,
I wish to use two switches to control two batteries as follows:
I want the bottom position to be off.
I want the center position to be battery contactor on and alternator
field on.
I want the top position to be e-bus alternate feed on and alternator
field off.
Is this doable? What kind of switch do I need. How would I wire it?
Thanks,
Ed Holyoke
Message 6
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--> AeroElectric-List message posted by: "Ed Holyoke" <bicyclop@pacbell.net>
Bob,
Sorry for not being more clear. My wife was calling me and I hurried to
complete and send without first proofreading.
I do want to turn off the contactor when I close the alternate feed.
Since I will have two batteries, each with the ability to feed the main
bus (and alternator field) and the e-bus, I'm not too worried about a
failure of one of the switches to take the whole system down. Should I
be?
It just occurred to me that, if I ignore the alternator field, it will
get power from the main bus any time that either contactor is closed and
unless the field breaker is pulled. Then I think I can use 2-10 switches
to open the contactors and close the alternate feeds with full down
being the both off position. Is this correct or is there a hazard in not
switching the alternator field with the master?
I'm trying to save panel space and make management of the busses simpler
(at least for me) by having all the functionality of each battery on one
switch each. Otherwise I would need four switches to get the same
functionality as the two switches I'm proposing and without the
(perceived) benefit of automatically disconnecting the contactor when I
go to the alt feed position. I just need to remember that if either
switch is in the alt feed position (all the way up) then the other
switch needs to be full up or full down. If the alternator goes belly
up, I would run on one battery only and if it runs down faster than
anticipated, I'd turn on the other battery and find a place to land
before I could run it down too.
On a related note, I have a swing down panel with fuse blocks on it for
main, e and one of the battery busses. The only thing on the other
battery bus would be an ignition for which I would use an inline fuse
holder or fusible link. It is about 3 feet from either of the batteries
and I'm thinking maybe I should use fusible links to protect them. I'm
planning to have a 40 amp alternator and two 17ah batteries. I'm looking
to feed the main bus with an 8awg from the connector between the battery
contactors, and the e-bus alternate feeds with 8awg feeders from each
battery though the switches as discussed above. Should any or all three
of these be fed through fusible links? If so, how would I go about
connecting a short piece of 12awg to the 8awg to make the link? I can't
seem to find any butt connectors larger than 10awg for sale. I guess I
could solder and heat shrink 'em.
Pax,
Ed Holyoke
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<nuckollsr@cox.net>
At 09:07 PM 2/7/2006 -0800, you wrote:
>--> AeroElectric-List message posted by: "Ed Holyoke"
<bicyclop@pacbell.net>
>
>Howdy,
>
>I wish to use two switches to control two batteries as follows:
>I want the bottom position to be off.
>I want the center position to be battery contactor on and alternator
>field on.
>I want the top position to be e-bus alternate feed on and alternator
>field off.
>
>Is this doable? What kind of switch do I need. How would I wire it?
Would you leave the battery contactor closed while the e-bus
alternate feed is closed? Are you sure you want a single device
to have this much control over your system's functionality.
It becomes a single point of failure for lots of stuff. There's
a reason why those functions are separated out into two switches
in the Z-figures.
Bob . . .
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
Message 7
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| Subject: | Re: Switch Question |
--> AeroElectric-List message posted by: "Dr. Peter Laurence" <Dr.Laurence@mbdi.org>
> Howdy,
>
> I wish to use two switches to control two batteries as follows:
> I want the bottom position to be off.
> I want the center position to be battery contactor on and alternator
> field on.
> I want the top position to be e-bus alternate feed on and alternator
> field off.
>
> Is this doable? What kind of switch do I need. How would I wire it?
>
> Thanks,
>
> Ed Holyoke
Ed,
I would not configure it this way. I would suggest the following:
Down-off
Middle- Battery contactor on
Up-Alternator(and battery on)
This config will not allow the alt to be energized without the battery on.
Utilize a single pole single throw switch for the e-buss.
If you need to de-energize the alternator, you can place the switch back to
the middleor pull the field breaker.
mtcw
Peter
>
>
>
Message 8
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| Subject: | Re: Wire sizing. |
--> AeroElectric-List message posted by: Bill Dube <william.p.dube@noaa.gov>
Robert L. Nuckolls, III wrote:
>Keep in mind too that the 0.5 volt value is a rule-of-thumb.
> Consider that we expect things to perform in a useful way all the
> way down to battery-only ops of 11.0 volts. That's a whole lot more
> than 0.5 volts below a 14.2 volt bus when alternator is operating
> normally. If your "thumb" should turn out to be 0.6 or 0.7 or even
> 0.8 volts long, it's not going to make a big difference in the
> over-all scheme of things.
Actually, 0.5 volts it is a maximum limit for 14 volt devices under continuous
operation set by the FAA.
AC-43.13-1B 11-66 b (Table 11-6)
You can read it yourself here:
http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/99c827db9baac81b86256b4500596c4e/$FILE/Chapter%2011.pdf
For incandescent position lights to put out their rated candlepower, they have
to get the proper voltage. If there is excessive drop, your lights will be too
dim, other folks might not see you as well, and .....
LED position lights (with regulators) are uneffected by any reasonable voltage
drop, but they only draw about 1/2 Amp, so there is not much drop anyway.
Bill Dube'
http://www.killacycle.com/Lights.htm
>At 02:25 PM 2/7/2006 -0700, you wrote:
>
>
>
>>--> AeroElectric-List message posted by: Bill Dube <william.p.dube@noaa.gov>
>>
>>Well I guess as long as he can make it from the switch to the wingtip
>>using less than 23 feet of wire, he can stay within the allowed 0.5 volt
>>drop using 16 gage wire.
>>
>>(4.81/1000)*4.4*23 = 0.5 volts
>>
>>The wing is about 10 feet long. I'm not sure how much wire it will take
>>to get from the wing root to the switch, but 10 feet might be a good
>>guess. Probably would be OK.
>>
>>
>
>
>
>
Message 9
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--> AeroElectric-List message posted by: "Ed Holyoke" <bicyclop@pacbell.net>
Howdy Peter,
I wasn't very clear. There would be two switches, one for each battery
allowing me to feed the main or e-bus with either or both battery(ies).
I'm not sure how the alternator field could be fed without a battery
contactor closed anyway. Your point is well taken that the alternator
can be taken off line by pulling the field breaker.
My latest thinking is to control the main and e-busses with two switches
as (poorly) described in my first post and rely on the field breaker for
ultimate alternator control. The breaker would not be powered if both of
the battery contactors (and with them, the main bus) were off. The
alternator field would be on line when either battery is powering the
main bus and the breaker is closed.
Pax,
Ed Holyoke
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Dr.
Peter Laurence
Sent: Wednesday, February 08, 2006 10:07 AM
Subject: Re: AeroElectric-List: Switch Question
--> AeroElectric-List message posted by: "Dr. Peter Laurence"
<Dr.Laurence@mbdi.org>
> Howdy,
>
> I wish to use two switches to control two batteries as follows:
> I want the bottom position to be off.
> I want the center position to be battery contactor on and alternator
> field on.
> I want the top position to be e-bus alternate feed on and alternator
> field off.
>
> Is this doable? What kind of switch do I need. How would I wire it?
>
> Thanks,
>
> Ed Holyoke
Ed,
I would not configure it this way. I would suggest the following:
Down-off
Middle- Battery contactor on
Up-Alternator(and battery on)
This config will not allow the alt to be energized without the battery
on.
Utilize a single pole single throw switch for the e-buss.
If you need to de-energize the alternator, you can place the switch back
to
the middleor pull the field breaker.
mtcw
Peter
>
>
>
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