Today's Message Index:
----------------------
1. 05:44 AM - Quickie Radios (jcrain2@juno.com)
2. 07:05 AM - Re: Simplification (Robert L. Nuckolls, III)
3. 07:13 AM - Re: Switched Pot (Robert L. Nuckolls, III)
4. 07:17 AM - Re: Which diode to use? (Robert L. Nuckolls, III)
5. 08:45 AM - Re: Switched Pot (Matt Prather)
6. 08:53 AM - Re: Warning light on Main and Aux Alternator installation (Robert L. Nuckolls, III)
7. 09:11 AM - Re: Locking female fast-ons (Charlie Kuss)
8. 09:11 AM - Re: Locking female fast on source needed (Charlie Kuss)
9. 09:29 AM - Simplification ()
10. 10:29 AM - Crimping 22AWG PIDG terminals (DAVID REEL)
11. 10:40 AM - Re: Simplification (David Carter)
12. 11:07 AM - Re: Simplification (echristley@nc.rr.com)
13. 12:36 PM - Re: Locking female fast-ons (John D. Heath)
14. 01:01 PM - Re: Locking female fast-ons (John D. Heath)
15. 03:47 PM - Re: Locking female fast-ons (David Carter)
16. 06:40 PM - Re: Simplification (LarryRobertHelming)
17. 06:47 PM - starter circuit simplification ()
18. 08:40 PM - Re: Simplification (David Carter)
Message 1
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--> AeroElectric-List message posted by: "jcrain2@juno.com" <jcrain2@juno.com>
I am hearing slight alternator noise in my headsets. Sometimes they are garbled
plus transp. doesn't always get through. I feel I need to separate my
com/intercom from the master solenoid and feed off the battery. I have already
installed the noise filter after the master solenoid.
Also the mic key makes the wing leveler turn plus the fuel gauge pegs out. Is
there an extra shielded coax that works with the B and C connectors or should I
pull some off of an other larger coax to double shield?
I have just a "whip antenna" with a metal screen ground plane. Would
the aluminum "Flying W" be better than a dipole flat metal ribbon that
"Spruce" advertises?
Is there an archive in Kit planes or could you FAX me a schematic showing parts
and hook ups for a fix?
Bruce Crain
Message 2
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| Subject: | Re: Simplification |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <rnuckolls@aeroelectric.com>
At 10:59 PM 8/25/2004 -0500, you wrote:
>--> AeroElectric-List message posted by: "David Carter"
><dcarter@datarecall.net>
>
>OC,
>
>Thanks for the clarification. I'm assuming that aircraft starters don't use
>the Bendix engagement system - too old and clunky?
Some modern products do use the Bendix style pinion engagement
mechanism. It's relatively simple and works well as long as it's
not badly worn or insufficiently lubricated. But like batteries
in most airplanes, they don't get attention until they have been
misbehaving for some time.
B&C chose not to go the Bendix route in a quest for the most
trouble free design with the longest service life we could deduce
at the time.
> The Z-diagrams show a
>starter "solenoid" - so that gadget is going to do the two things - provide
>current to motor and move the pinion gear to engage the flywheel.
If you're talking about the circle perched right on top of the
"STARTER" symbol, yes. That is a combination electrical control
contactor and pinion gear engagement solenoid. See:
http://www.aeroelectric.com/articles/strtctr.pdf
Some of the earliest revisions to the Z-figures were driven by
a late discovery of the very high inrush currents demanded by
this style of starter contactor/solenoid mechanism. When installing
this starter on an airplane with a keyswitch, the solenoid would
be VERY hard on the starter contacts of the switch.
Had a guy working for me about 15 years ago that had some brand
of small Japanese car. It wouldn't start one afternoon in the
parking lot of my business. We got out the meter and trouble shot
the system to discover that the starter switch in the key lock
was not closing. Upon disassembly of the switch, we found the
brass contacts of the starter circuit blackened and burned away.
He noted that the starter had been flaky for several months before
it quit. A new switch "fixed" it . . . an external contactor added
on as suggested in the Z-figures would have made the problem
go away for the lifetime of the car.
This is what drove the recommendation for an external contactor
as shown in Figure 6 of the article and explained in the last
few paragraphs.
>So, looks like us two proponents of "simplification" are suggesting use of a
>manual battery switch which then allows the elimination of the "starter
>contactor" in the Z- drawings, i.e., #2awg fat wire goes from downstream
>side of manual batt sw to fat wire terminal on starter solenoid (instead of
>to upstream side of a starter contactor) and the push-to-start wire goes to
>the starter solenoid coils instead of the "eliminated starter contactor
>coils".
You have unrelated things tied together. The use of a manual battery
switch has no bearing on your style of starter or even if you have
a starter. Many aircraft have used manual switches in years past.
The Tri-Pacer in which I took dual instruction in 1961 had the battery
mounted under the right seat. The battery master was a fat toggle
under the front edge of the seat. You can have a mechanical switch
for ANY battery installation on any airplane whether or not it has
a starter.
You can use the starter's built in contactor/solenoid as shown
in Figure 6 of the article . . . just be aware of the special
stresses on what ever switch you use to energize the contactor/solenoid.
There are heavy duty push-buttons offered by many industrial
and heavy automotive supply houses that would be fine. I've not
conducted any tests on driving this bad-mamma contactor through
a fuse. You may find it necessary to use a 15A fuse and 14AWG
wire for your push-button circuit so that the inrush current doesn't
nuisance-trip the fuse.
Parts count reduction is a good thing generally. Just be aware
that not all parts shown in the Z-figures were added purely for
the sake of some convenience. We've been trading off service life,
reliability, installed weight, wire routing and convenience
issues for decades. I'd like to think that the Z-figures
represent a distilled approach that has a considered
purpose for each component. Compared to the way we
can hose up the electrical system architecture in a biz jet,
the z-figures are stone simple. Efforts toward further
simplification should be supported by a through understanding
of the thought processes by which proposed "excess parts" were
included.
Bob . . .
---
Message 3
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| Subject: | Re: Switched Pot |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <rnuckolls@aeroelectric.com>
At 09:45 PM 8/25/2004 -0700, you wrote:
>--> AeroElectric-List message posted by: Geoff Evans
><hellothaimassage@yahoo.com>
>
>I recently bought a couple of the Vans dimmers for cockpit lighting. They
>come with a miniature (1/4" mount, 1/8" shaft) 1K pot.
>
>The suggested wiring diagram shows getting 12V from the nav light switch --
>i.e. when the nav lights are on, the cockpit lights are on. However, it seems
>to me that the cockpit lights should have a separate fuse. Why lose the
>cockpit lighting if you happen to blow the fuse for the nav lights?
Minimal cockpit lighting should be on its own fuse off the e-bus.
How much current does your lighting system draw in the minimum light
mode for flight in full darkness. I would have two lighting systems.
A panel flood that runs from the e-bus that draws perhaps 100 mA max.
The big-kahuna lighting system would fuse from the main bus and have
a dimmer control set up for min-max voltage tailored for how the lights
operate. OFF is at about 4 volts for an incandescent lamp. Our dimmers
are set up for 4-max volts over the full rotation of the pot. No
toggle switch is recommended. It only adds to parts count, takes up
panel space and offers no operational advantages. Don't want lights?
Turn them down to min output of 4v and call them "off" . . . lamp life
at this voltage level is somewhere between a very long time and forever.
Current draw under this condition is insignificant.
>So, since I don't want to install a separate toggle switch, I'm looking for a
>1K miniature pot that has a switch at the fully counter-clockwise position.
>I'd like one with the same exterior parameters as the original pot -- namely,
>a 1/4" mounting hole, a 1/8" shaft, and solder terminals on the back (as
>opposed to on the side).
>
>The Digikey catalog has a bazillion different variants of these things, and
>I'm not sure which one to order. Can someone point me in the right direction,
>preferably with an exact part number or the like?
Pots with switches are now almost totally non-existent. They were
popular when volume controls were also tasked with turning power
on and off for a radio. This technique is seldom used for anything
other than $4 pocket radios. I'd suggest you set up your dimming
for the voltage control range cited above, have perhaps two lighting
systems independently fused and split between the two busses and
include NO toggle switches.
Bob . . .
---
Message 4
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| Subject: | Re: Which diode to use? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <rnuckolls@aeroelectric.com>
At 07:00 PM 8/25/2004 -0700, you wrote:
>--> AeroElectric-List message posted by: "Dr. Andrew Elliott"
><a.s.elliott@cox.net>
>
>Folks:
>
>I have discovered that the aux power outlet (i.e. cigarette lighter
>socket) in my non-ABAM plane is wired without any protection against
>back-feeding the bus. That is, if I plug in my 17-79 headset to
>recharge the internal battery, and forget that I did so, then when I
>shut down the plane the 9V headset battery provides at least enough
>power to light up the "alternator off" warning light.
>
>I would like to add a diode to the system to prevent this. In the
>forward direction, the socket is protected by a 5A fuse. What would be
>the appropriate size/rating of a diode to add to the line? And what
>would be the best way to wire it in?
I'd add this diode to the power cable for the headset. The
power needed by this system is quite small. A 1-amp rated diode
from radio shack would suffice. See the 1N400x series diodes
at:
http://www.radioshack.com/search.asp?cookie%5Ftest=1&find=diode&hp=search&image1.x=0&image1.y=0&image1=submit&SRC=1
Wire one into the + power lead for the headset with the banded
end of the diode facing the headset.
Bob . . .
---
Message 5
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| Subject: | Re: Switched Pot |
--> AeroElectric-List message posted by: "Matt Prather" <mprather@spro.net>
Hi Geoff,
Bob already sent a good reply to this. However, if your heart is set
on having a switch control the panel lights, a double pole switch might
be the way to go. Such a switch has two power inputs as well as two
switched outputs - isolated. I propose that you use 2 seperately fused
inputs to the switch - one for the nav, one for the panel.
Regards,
Matt-
> --> AeroElectric-List message posted by: Geoff Evans
> <hellothaimassage@yahoo.com>
>
> I recently bought a couple of the Vans dimmers for cockpit lighting.
> They come with a miniature (1/4" mount, 1/8" shaft) 1K pot.
>
> The suggested wiring diagram shows getting 12V from the nav light switch
> -- i.e. when the nav lights are on, the cockpit lights are on. However,
> it seems to me that the cockpit lights should have a separate fuse. Why
> lose the cockpit lighting if you happen to blow the fuse for the nav
> lights?
>
> So, since I don't want to install a separate toggle switch, I'm looking
> for a 1K miniature pot that has a switch at the fully counter-clockwise
> position. I'd like one with the same exterior parameters as the original
> pot -- namely, a 1/4" mounting hole, a 1/8" shaft, and solder terminals
> on the back (as opposed to on the side).
>
> The Digikey catalog has a bazillion different variants of these things,
> and I'm not sure which one to order. Can someone point me in the right
> direction, preferably with an exact part number or the like?
>
> Thanks.
> -Geoff
> RV-8
>
>
> _______________________________
>
>
Message 6
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aeroelectric-list@matronics.com
| Subject: | Re: Warning light on Main and Aux Alternator installation |
lus.com>
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:26 AM 8/26/2004 -0700, you wrote:
>Bob, I posted (thought I posted) this question to the aeroelectric list, but
>got no responses. Can a single LO/OV module work with a 2 alternator, Main
>and EBuss system as I envision? If not, is there a way?
>Thx
>Randy
Not real sure what the question is. What Z-figure are we talking
about? You talke about a "504-1 module" is this the S704-1
disconnect relay combined with an OVM-14 crowbar OV module?
I'm not visualizing how you would wire all this stuff together.
Let's pick a z-figure and then describe how it's modified.
>--> AeroElectric-List message posted by: "McFarland, Randy"
><Randy.McFarland@novellus.com>
>
>Could we not feed the 504-1 module with power from both the Main and
>Essential busses? When the Main Alternator failed the light would come on
>because the E Buss switch would be open so power would be lost to both
>busses momentarily,
When an alternator quits, NO busses loose power. The voltage
simple falls from 13.8 to 14.6 volts down to 12.6 or below.
Everything continues to function and the low voltage warning
light begins to flash.
> and then go off when the E Buss switch is closed
>providing 12v again to the 504 module?
>Randy
I think your mixing up the functionality of two separate systems.
The S704-1/OVM-14 combination is for control of the SD-8 and OV protection.
This task is separate and independent of altenrator failure warning
by some active form of low voltage warning . . . either by our
LVW/ABMM module, -OR- the low volts warning built into a B&C LR-3, -OR-
any other form of LV WARN you plan to incorporate to watch the main
bus voltage.
I presume you're talking about Figure Z-13. What changes would
you perceive to be useful?
Bob . . .
Message 7
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| Subject: | Re: Locking female fast-ons |
--> AeroElectric-List message posted by: Charlie Kuss <chaztuna@adelphia.net>
John
Waytek is where I bought the relays, sockets and the 16/14 AWG terminals.
They don't have 1/4" wide terminals for 22/18 AWG wire. The terminals shown
for that size wire are 3/16"
Charlie
>--> AeroElectric-List message posted by: "John D. Heath" <alto_q@direcway.com>
>
>Try this link. www.waytekwire.com
>
> John D.
>
>DO NOT ARCHIVE
>----- Original Message -----
>From: <bakerocb@cox.net>
>To: <aeroelectric-list@matronics.com>
>Subject: AeroElectric-List: Locking female fast-ons
>
>
> > --> AeroElectric-List message posted by: <bakerocb@cox.net>
> >
> > AeroElectric-List message previously posted by: Charlie Kuss
> > <chaztuna@adelphia.net>
> >
> > Listers, I recently purchased several Bosch (automotive style) relays and
> > the
> > related sockets for my RV-8A flap circuit. I purchased these items from
> > Waytek Wire. Nice folks with brand name stuff at good prices. The
> > sockets for these relays use a variant of the common 1/4" female fast ons.
> > These are open barrel, rather than PIDG items. They also have a locking
> > tang,
> > to secure the connector into the socket body. Anyone familiar with
> > automotive connectors has seen these.My question is, I need to find a part
> > number and source for these connectors designed for 22/18 AWG wire. Waytek
> > has these connectors
> > for 16/14 AWG, but not for the 22/18 AWG. I know that these things are
> > actually quite common. I've tried finding them in Allied Electronics
> > paper catalog and their web site. However, I don't know the manufacturer
> > or
> > the proper terminology these items are known by. Because of this, I have
> > not been able to locate what I need. Can anyone help?
> > The relay sockets and connectors can be seen here:
> > http://order.waytekwire.com/IMAGES/M37/catalog/216_54
> > I'm using the #75280 style sockets. These are modular. You can stack
> > them together. The connectors are part # 31073, also seen on the above web
> > page. Charlie Kuss RV-8A cockpit wiring & systems>>
> >
> > 8/25/2004
> >
> > Hello Charlie, Why wouldnt an Avikrimp female .250 push on terminal work?
> > You can get them in either insulated (AA-8140) or uninsulated (AA-1140F)
> > configuration. (Also fully insulated, but you dont want that here).Just do
> > a google search.
> >
> > Yes they are the high quality complete surround PIDG crimp on type
> > terminals, not open barrel, and the lock on feature may not be a perfect
> > match with the lock on built into the socket body, but Ill bet they
> > wouldnt come loose from the male terminal inside the socket body.
> >
> > I use the Avikrimp fully insulated male and female terminals as in-line
> > connectors in much of my wiring. One draw back is that when I want to
> > separate them it takes holding the inner shell with a pliers and twisting
> > a broad blade screwdriver between the side of the pliers and the end of
> > the outer shell to separate them. The make positive connection.
> >
> > OC
> >
> >
> >
>
>
Message 8
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| Subject: | Locking female fast on source needed |
--> AeroElectric-List message posted by: Charlie Kuss <chaztuna@adelphia.net>
Bob
I'm not going to use a "pre wired" socket. I don't like the PVC insulated
wire on them.
Charlie
>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
><rnuckolls@aeroelectric.com>
>
>At 10:09 PM 8/25/2004 -0500, you wrote:
>
> >--> AeroElectric-List message posted by: "William Slaughter"
> ><willslau@alumni.rice.edu>
> >
> >This is not a knock on the relay pigtail or similar connectors, but they
> >are not a required part. Let's not lose sight of the fact that you can
> >simply attach regular female fast-ons to the male lugs on the relays.
> >Just a thought....
>
> That's what I've always recommended. I KNOW the quality of a PIDG
> fast-on female connector. I don't know the quality of the connectors
> supplied with the pre-wired sockets or socket kits. One should
> not need to replace these relays very often . . . not having them
> on a socket is a minor risk/inconvenience.
>
> Bob . . .
>
>
>---
>
>
Message 9
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--> AeroElectric-List message posted by: <bakerocb@cox.net>
8/26/2004
Hello David, I will respond in pieces below:
AeroElectric-List message posted by: "David Carter" <dcarter@datarecall.net>
<< OC, Thanks for the clarification. I'm assuming that aircraft starters
don't use the Bendix engagement system - too old and clunky? >>
That statement is a little too sweeping. I think it would be more accurate to say
that many recent modern design aircraft starters do not use the Bendix spiral
gear mechanism, but instead use a solenoid to engage and disengage the starter
pinion gear. Until the fairly recent arrival of the aviation engine light
weight starters installation of the heavy, clunky, and maintenance needy Bendix
mechanism was widespread and thousands of airplanes are still flying with it
today.
<<The Z-diagrams show a starter "solenoid" - so that gadget is going to do the
two things
provide current to motor and move the pinion gear to engage the flywheel.>>
Yes. On those Z diagrams with the little circle with the letters SOL inside drawn
next to the STARTER circle that is what is being portrayed. But notice on Z-18
for the LOM engine there is no SOL next to the starter. Presumably the LOM
engine uses a starter with a Bendix or some other method of starting.
<<So, looks like us two proponents of "simplification" are suggesting use
of a manual battery switch which then allows the elimination of the "starter
contactor" in the Z- drawings,>>
I dont see that installation of a manual battery switch is a mandatory precedence
to eliminating the starter contactor. Either one should be able to be implemented
independent of each other. I have not arrived at the design point of abandoning
the battery contactor. My KIS TR-1 is completed (they never are really)
and flying and my next project (bigger and faster) is still in the wife convincing
stage.
<<i.e., #2awg fat wire goes from downstream side of manual batt sw to fat wire
terminal on starter solenoid (instead of to upstream side of a starter contactor)
and the push-to-start wire goes to the starter solenoid coils instead of
the "eliminated starter contactor
coils". Sound reasonable and without some bad operational quirk I've not
thought of? David>>
What you describe is exactly how I understand it. Obviously some modification of
the starter wiring is going to be required because as designed the electricity
going to the input fat wire terminal on the starter solenoid also goes at the
same time to the coil on the solenoid. The result is movement of the solenoid
slug which completes the electrical circuit to the starter motor and moves
the pinion gear into contact. Since your plan calls for activation of the solenoid
coil independently after the fact that electricity is already at the starter
input point means some starter wiring modification is required.
Now two caveats both from Bob Nuckolls in passing in the 8/24/04 aeroelectric-list:
1) Bob mentions some sort of relay near the starter to handle in rush current in
the above scenario. This is a mystery to me. You might want to seek clarification
from him.
2) Bob mentions the separate starter contactor as recommended by B&C. I intend
to contact them and ask why. I will report back.
OC
Message 10
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| Subject: | Crimping 22AWG PIDG terminals |
--> AeroElectric-List message posted by: "DAVID REEL" <dreel@cox.net>
Has anyone had problems getting a good crimp with Cleveland Tools WTC380 ratchet
terminal crimper? I cannot get the 18-22 AWG terminals to firmly grab 22AWG
wire. Even doubling the wire doesn't make a firm connection. So far I'm 0 out
of 4 tries. The crimper otherwise seems good on the other sizes but the 18-22
size is out on the far end of the tool & I'm suspecting some flexing. Though
I'm not an experienced crimper, the whole thing seems pretty idiot proof so
I can't imagine what else might be wrong. The PIDG terminals came from B&C.
Dave Reel - RV8A
Message 11
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| Subject: | Re: Simplification |
--> AeroElectric-List message posted by: "David Carter" <dcarter@datarecall.net>
Bob & OC,
Thanks for the nice replies. Bob, your article on starters and circuit
evolution is great.
The only reason I "linked" manual batt sw and elim of starter contactor was
the issue of "killing the fat wire to the starter" - i.e., if the starter
contactor is eliminated, and the fat wire is hot all the time the battery sw
is "on", and then, someday, the starter "runs on" after I release the start
button - some other way of killing that wire is needed - the manual battery
sw does that. Oh, so does a normal battery contactor. Oh, so, there is no
linkage. Either one works the same. Boy, I'm slow.
I appreciate the issue of "stress" on the starter switch, i.e., it ought not
be subjected to current (inrush) that adversely shortens its life. The
starter contactor is a good solution. But, with respect to that
"evolutionary or evolved" refinement of the starter circuits - and I don't
mean any disrespect for something that works and is in general practice -
but adding a contactor to protect a switch from premature death is a
work-around or substitute for getting a better switch. Now, as I say that,
I know that cars and non-OBAM aircraft operators aren't and can't,
respectively, going to go put in a better switch, so the starter contactor
becomes the elegantly simple and reasonable solution.
- However, for us OBAMers, I'd rather get one of those heavy duty
industrial grade "push to start" switches Bob mentioned in his reply. Fits
in with the idea of parts simplification and using better stuff than
non-OBAM are permitted to use.
I'll have to pick a starter that can be readily modified to unhook (or cut)
the solenoid coil's power lead from the "fat wire terminal" and have it get
its power from my industrial grade push button (Hey!! If all else fails I
could use a knife switch & watch the big blue spark when I disconnect the
starter - wouldn't that look cool? (or kooky?)
Thanks, again for the great info and help "understanding the physics
involved".
David
----- Original Message -----
From: "Robert L. Nuckolls, III" <rnuckolls@aeroelectric.com>
Subject: Re: AeroElectric-List: Simplification
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<rnuckolls@aeroelectric.com>
>
> At 10:59 PM 8/25/2004 -0500, you wrote:
>
> >--> AeroElectric-List message posted by: "David Carter"
> ><dcarter@datarecall.net>
> >
> >OC,
> >
> >Thanks for the clarification. I'm assuming that aircraft starters don't
use
> >the Bendix engagement system - too old and clunky?
>
> Some modern products do use the Bendix style pinion engagement
> mechanism. It's relatively simple and works well as long as it's
> not badly worn or insufficiently lubricated. But like batteries
> in most airplanes, they don't get attention until they have been
> misbehaving for some time.
>
> B&C chose not to go the Bendix route in a quest for the most
> trouble free design with the longest service life we could deduce
> at the time.
>
>
> > The Z-diagrams show a
> >starter "solenoid" - so that gadget is going to do the two things -
provide
> >current to motor and move the pinion gear to engage the flywheel.
>
> If you're talking about the circle perched right on top of the
> "STARTER" symbol, yes. That is a combination electrical control
> contactor and pinion gear engagement solenoid. See:
>
> http://www.aeroelectric.com/articles/strtctr.pdf
>
> Some of the earliest revisions to the Z-figures were driven by
> a late discovery of the very high inrush currents demanded by
> this style of starter contactor/solenoid mechanism. When installing
> this starter on an airplane with a keyswitch, the solenoid would
> be VERY hard on the starter contacts of the switch.
>
> Had a guy working for me about 15 years ago that had some brand
> of small Japanese car. It wouldn't start one afternoon in the
> parking lot of my business. We got out the meter and trouble shot
> the system to discover that the starter switch in the key lock
> was not closing. Upon disassembly of the switch, we found the
> brass contacts of the starter circuit blackened and burned away.
> He noted that the starter had been flaky for several months before
> it quit. A new switch "fixed" it . . . an external contactor added
> on as suggested in the Z-figures would have made the problem
> go away for the lifetime of the car.
>
> This is what drove the recommendation for an external contactor
> as shown in Figure 6 of the article and explained in the last
> few paragraphs.
>
>
> >So, looks like us two proponents of "simplification" are suggesting use
of a
> >manual battery switch which then allows the elimination of the "starter
> >contactor" in the Z- drawings, i.e., #2awg fat wire goes from downstream
> >side of manual batt sw to fat wire terminal on starter solenoid (instead
of
> >to upstream side of a starter contactor) and the push-to-start wire goes
to
> >the starter solenoid coils instead of the "eliminated starter contactor
> >coils".
>
> You have unrelated things tied together. The use of a manual battery
> switch has no bearing on your style of starter or even if you have
> a starter. Many aircraft have used manual switches in years past.
> The Tri-Pacer in which I took dual instruction in 1961 had the battery
> mounted under the right seat. The battery master was a fat toggle
> under the front edge of the seat. You can have a mechanical switch
> for ANY battery installation on any airplane whether or not it has
> a starter.
>
> You can use the starter's built in contactor/solenoid as shown
> in Figure 6 of the article . . . just be aware of the special
> stresses on what ever switch you use to energize the
contactor/solenoid.
> There are heavy duty push-buttons offered by many industrial
> and heavy automotive supply houses that would be fine. I've not
> conducted any tests on driving this bad-mamma contactor through
> a fuse. You may find it necessary to use a 15A fuse and 14AWG
> wire for your push-button circuit so that the inrush current doesn't
> nuisance-trip the fuse.
>
> Parts count reduction is a good thing generally. Just be aware
> that not all parts shown in the Z-figures were added purely for
> the sake of some convenience. We've been trading off service life,
> reliability, installed weight, wire routing and convenience
> issues for decades. I'd like to think that the Z-figures
> represent a distilled approach that has a considered
> purpose for each component. Compared to the way we
> can hose up the electrical system architecture in a biz jet,
> the z-figures are stone simple. Efforts toward further
> simplification should be supported by a through understanding
> of the thought processes by which proposed "excess parts" were
> included.
>
> Bob . . .
Message 12
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| Subject: | Re: Simplification |
--> AeroElectric-List message posted by: echristley@nc.rr.com
>
> This is why I'm a little miffed when a newby
writes to say,
> "I'm using
> Figure Z-xx but I've incorporated a few ideas
of my own." He then
> lists all the things he plans to do and wants
on-the-spot critical
> review. I have to explain that the best thing
to do is pick a
> figure as published and then let's discuss any
perceived
> shortcomings one
> at a time. If there is merit to alternative
architectures, we'll
> publish it and get feedback from the rest of
the community. That's
> how Appendix Z has grown and will continue to grow.
>
>
Bob, I haven't purchased the book...yet. I have to
many task with the requisite purchases and education
in the way before I get down to designing the
electrical system. I figure by the time I purchase
the book, it'll have evolved another generation or two.
That being said, how are changes tracked in the
book. Are the changes listed with a short paragraph
as to why? I often ask naive question when I can't
understand the 'why' of a particular technique that
is not used. Once I find out what the 'why' is, the
answer is often more illuminating than the 'why's
dealing with what IS used.
Again, I don't have the book, but if this is done
then newbie questions of this type should get a curt
RTFM.
Message 13
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|
| Subject: | Re: Locking female fast-ons |
--> AeroElectric-List message posted by: "John D. Heath" <alto_q@direcway.com>
Then try this link.
http://order.waytekwire.com/CGI-BIN/LANSAWEB?WEBEVENT+L0878E15E8C41113EE825992+M37+ENG
It says 1/4". Copy and Paste.
John D.
----- Original Message -----
From: "Charlie Kuss" <chaztuna@adelphia.net>
Subject: Re: AeroElectric-List: Locking female fast-ons
> --> AeroElectric-List message posted by: Charlie Kuss
> <chaztuna@adelphia.net>
>
> John
> Waytek is where I bought the relays, sockets and the 16/14 AWG terminals.
> They don't have 1/4" wide terminals for 22/18 AWG wire. The terminals
> shown
> for that size wire are 3/16"
> Charlie
>
>>--> AeroElectric-List message posted by: "John D. Heath"
>><alto_q@direcway.com>
>>
>>Try this link. www.waytekwire.com
>>
>> John D.
>>
>>DO NOT ARCHIVE
>>----- Original Message -----
>>From: <bakerocb@cox.net>
>>To: <aeroelectric-list@matronics.com>
>>Subject: AeroElectric-List: Locking female fast-ons
>>
>>
>> > --> AeroElectric-List message posted by: <bakerocb@cox.net>
>> >
>> > AeroElectric-List message previously posted by: Charlie Kuss
>> > <chaztuna@adelphia.net>
>> >
>> > Listers, I recently purchased several Bosch (automotive style) relays
>> > and
>> > the
>> > related sockets for my RV-8A flap circuit. I purchased these items from
>> > Waytek Wire. Nice folks with brand name stuff at good prices. The
>> > sockets for these relays use a variant of the common 1/4" female fast
>> > ons.
>> > These are open barrel, rather than PIDG items. They also have a locking
>> > tang,
>> > to secure the connector into the socket body. Anyone familiar with
>> > automotive connectors has seen these.My question is, I need to find a
>> > part
>> > number and source for these connectors designed for 22/18 AWG wire.
>> > Waytek
>> > has these connectors
>> > for 16/14 AWG, but not for the 22/18 AWG. I know that these things are
>> > actually quite common. I've tried finding them in Allied Electronics
>> > paper catalog and their web site. However, I don't know the
>> > manufacturer
>> > or
>> > the proper terminology these items are known by. Because of this, I
>> > have
>> > not been able to locate what I need. Can anyone help?
>> > The relay sockets and connectors can be seen here:
>> > http://order.waytekwire.com/IMAGES/M37/catalog/216_54
>> > I'm using the #75280 style sockets. These are modular. You can stack
>> > them together. The connectors are part # 31073, also seen on the above
>> > web
>> > page. Charlie Kuss RV-8A cockpit wiring & systems>>
>> >
>> > 8/25/2004
>> >
>> > Hello Charlie, Why wouldnt an Avikrimp female .250 push on terminal
>> > work?
>> > You can get them in either insulated (AA-8140) or uninsulated
>> > (AA-1140F)
>> > configuration. (Also fully insulated, but you dont want that here).Just
>> > do
>> > a google search.
>> >
>> > Yes they are the high quality complete surround PIDG crimp on type
>> > terminals, not open barrel, and the lock on feature may not be a
>> > perfect
>> > match with the lock on built into the socket body, but Ill bet they
>> > wouldnt come loose from the male terminal inside the socket body.
>> >
>> > I use the Avikrimp fully insulated male and female terminals as in-line
>> > connectors in much of my wiring. One draw back is that when I want to
>> > separate them it takes holding the inner shell with a pliers and
>> > twisting
>> > a broad blade screwdriver between the side of the pliers and the end of
>> > the outer shell to separate them. The make positive connection.
>> >
>> > OC
>> >
>> >
>> >
>>
>>
>
>
Message 14
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|
| Subject: | Re: Locking female fast-ons |
--> AeroElectric-List message posted by: "John D. Heath" <alto_q@direcway.com>
What you want, finally penetrated my thick Skull. I don't think I've ever
seen 1/4" QC for 18/22 AWG. I even went and looked in my electrical stuff ,
nothing. I'm afraid I'd be into strip it, twist it, double it, Solder it,
and crimp it.
John D.
----- Original Message -----
From: "Charlie Kuss" <chaztuna@adelphia.net>
Subject: Re: AeroElectric-List: Locking female fast-ons
> --> AeroElectric-List message posted by: Charlie Kuss
> <chaztuna@adelphia.net>
>
> John
> Waytek is where I bought the relays, sockets and the 16/14 AWG terminals.
> They don't have 1/4" wide terminals for 22/18 AWG wire. The terminals
> shown
> for that size wire are 3/16"
> Charlie
>
>>--> AeroElectric-List message posted by: "John D. Heath"
>><alto_q@direcway.com>
>>
>>Try this link. www.waytekwire.com
>>
>> John D.
>>
>>DO NOT ARCHIVE
>>----- Original Message -----
>>From: <bakerocb@cox.net>
>>To: <aeroelectric-list@matronics.com>
>>Subject: AeroElectric-List: Locking female fast-ons
>>
>>
>> > --> AeroElectric-List message posted by: <bakerocb@cox.net>
>> >
>> > AeroElectric-List message previously posted by: Charlie Kuss
>> > <chaztuna@adelphia.net>
>> >
>> > Listers, I recently purchased several Bosch (automotive style) relays
>> > and
>> > the
>> > related sockets for my RV-8A flap circuit. I purchased these items from
>> > Waytek Wire. Nice folks with brand name stuff at good prices. The
>> > sockets for these relays use a variant of the common 1/4" female fast
>> > ons.
>> > These are open barrel, rather than PIDG items. They also have a locking
>> > tang,
>> > to secure the connector into the socket body. Anyone familiar with
>> > automotive connectors has seen these.My question is, I need to find a
>> > part
>> > number and source for these connectors designed for 22/18 AWG wire.
>> > Waytek
>> > has these connectors
>> > for 16/14 AWG, but not for the 22/18 AWG. I know that these things are
>> > actually quite common. I've tried finding them in Allied Electronics
>> > paper catalog and their web site. However, I don't know the
>> > manufacturer
>> > or
>> > the proper terminology these items are known by. Because of this, I
>> > have
>> > not been able to locate what I need. Can anyone help?
>> > The relay sockets and connectors can be seen here:
>> > http://order.waytekwire.com/IMAGES/M37/catalog/216_54
>> > I'm using the #75280 style sockets. These are modular. You can stack
>> > them together. The connectors are part # 31073, also seen on the above
>> > web
>> > page. Charlie Kuss RV-8A cockpit wiring & systems>>
>> >
>> > 8/25/2004
>> >
>> > Hello Charlie, Why wouldnt an Avikrimp female .250 push on terminal
>> > work?
>> > You can get them in either insulated (AA-8140) or uninsulated
>> > (AA-1140F)
>> > configuration. (Also fully insulated, but you dont want that here).Just
>> > do
>> > a google search.
>> >
>> > Yes they are the high quality complete surround PIDG crimp on type
>> > terminals, not open barrel, and the lock on feature may not be a
>> > perfect
>> > match with the lock on built into the socket body, but Ill bet they
>> > wouldnt come loose from the male terminal inside the socket body.
>> >
>> > I use the Avikrimp fully insulated male and female terminals as in-line
>> > connectors in much of my wiring. One draw back is that when I want to
>> > separate them it takes holding the inner shell with a pliers and
>> > twisting
>> > a broad blade screwdriver between the side of the pliers and the end of
>> > the outer shell to separate them. The make positive connection.
>> >
>> > OC
>> >
>> >
>> >
>>
>>
>
>
>
Message 15
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|
| Subject: | Re: Locking female fast-ons |
--> AeroElectric-List message posted by: "David Carter" <dcarter@datarecall.net>
The link didn't work. I went to www.waytekwire.com , clicked top left
"Products" link, scrolled way down to "Select a catagory", scrolled down to
"Terminals, push on", got listing of 6 items and clicked first item, "Fully
Insulated Female", scrolled to bottom and clicked the red text "22-18 GA
FEMALE PUSH-ON RED NYLON INS W/EXTRA SLEEVE" and got info but no size, and
looked at lower rt corner and clicked "...view the catalog" and got the full
info on full range of selections, including 1/4" insulated and non-insulated
pushons. The fully insultated should be good for use with the male blades
on the auto relays.
I called - they are coated with bright tin. The option of "extra sleeve" is
for strain relief to grip the insulation - you crimp them twice, once for
electrical connection on bare end of wire, 2nd on insulated wire, just like
we like. The 1/4" female fully insulated with extra sleeve for 22-18ga was
p/n 30713.
Min order is about 50 he said. Sounds like we need to get A/C Spruce and
Wicks to stock these beauties.
David
----- Original Message -----
From: "John D. Heath" <alto_q@direcway.com>
Subject: Re: AeroElectric-List: Locking female fast-ons
> --> AeroElectric-List message posted by: "John D. Heath"
<alto_q@direcway.com>
>
> Then try this link.
>
>
http://order.waytekwire.com/CGI-BIN/LANSAWEB?WEBEVENT+L0878E15E8C41113EE825992+M37+ENG
>
> It says 1/4". Copy and Paste.
>
> John D.
>
> ----- Original Message -----
> From: "Charlie Kuss" <chaztuna@adelphia.net>
> To: <aeroelectric-list@matronics.com>
> Subject: Re: AeroElectric-List: Locking female fast-ons
>
>
> > --> AeroElectric-List message posted by: Charlie Kuss
> > <chaztuna@adelphia.net>
> >
> > John
> > Waytek is where I bought the relays, sockets and the 16/14 AWG
terminals.
> > They don't have 1/4" wide terminals for 22/18 AWG wire. The terminals
> > shown
> > for that size wire are 3/16"
> > Charlie
> >
> >>--> AeroElectric-List message posted by: "John D. Heath"
> >><alto_q@direcway.com>
> >>
> >>Try this link. www.waytekwire.com
> >>
> >> John D.
> >>
> >>DO NOT ARCHIVE
> >>----- Original Message -----
> >>From: <bakerocb@cox.net>
> >>To: <aeroelectric-list@matronics.com>
> >>Subject: AeroElectric-List: Locking female fast-ons
> >>
> >>
> >> > --> AeroElectric-List message posted by: <bakerocb@cox.net>
> >> >
> >> > AeroElectric-List message previously posted by: Charlie Kuss
> >> > <chaztuna@adelphia.net>
> >> >
> >> > Listers, I recently purchased several Bosch (automotive style) relays
> >> > and
> >> > the
> >> > related sockets for my RV-8A flap circuit. I purchased these items
from
> >> > Waytek Wire. Nice folks with brand name stuff at good prices. The
> >> > sockets for these relays use a variant of the common 1/4" female fast
> >> > ons.
> >> > These are open barrel, rather than PIDG items. They also have a
locking
> >> > tang,
> >> > to secure the connector into the socket body. Anyone familiar with
> >> > automotive connectors has seen these.My question is, I need to find a
> >> > part
> >> > number and source for these connectors designed for 22/18 AWG wire.
> >> > Waytek
> >> > has these connectors
> >> > for 16/14 AWG, but not for the 22/18 AWG. I know that these things
are
> >> > actually quite common. I've tried finding them in Allied Electronics
> >> > paper catalog and their web site. However, I don't know the
> >> > manufacturer
> >> > or
> >> > the proper terminology these items are known by. Because of this, I
> >> > have
> >> > not been able to locate what I need. Can anyone help?
> >> > The relay sockets and connectors can be seen here:
> >> > http://order.waytekwire.com/IMAGES/M37/catalog/216_54
> >> > I'm using the #75280 style sockets. These are modular. You can stack
> >> > them together. The connectors are part # 31073, also seen on the
above
> >> > web
> >> > page. Charlie Kuss RV-8A cockpit wiring & systems>>
> >> >
> >> > 8/25/2004
> >> >
> >> > Hello Charlie, Why wouldnt an Avikrimp female .250 push on terminal
> >> > work?
> >> > You can get them in either insulated (AA-8140) or uninsulated
> >> > (AA-1140F)
> >> > configuration. (Also fully insulated, but you dont want that
here).Just
> >> > do
> >> > a google search.
> >> >
> >> > Yes they are the high quality complete surround PIDG crimp on type
> >> > terminals, not open barrel, and the lock on feature may not be a
> >> > perfect
> >> > match with the lock on built into the socket body, but Ill bet they
> >> > wouldnt come loose from the male terminal inside the socket body.
> >> >
> >> > I use the Avikrimp fully insulated male and female terminals as
in-line
> >> > connectors in much of my wiring. One draw back is that when I want to
> >> > separate them it takes holding the inner shell with a pliers and
> >> > twisting
> >> > a broad blade screwdriver between the side of the pliers and the end
of
> >> > the outer shell to separate them. The make positive connection.
> >> >
> >> > OC
> >> >
> >> >
> >> >
> >>
> >>
> >
> >
>
>
Message 16
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| Subject: | Re: Simplification |
--> AeroElectric-List message posted by: "LarryRobertHelming" <lhelming@sigecom.net>
David, the primary concern I have with running the big-o-boy start
button/switch is that heavy and high amp wire runs all the way from its
power source (the battery) to your panel switch and then on to the starter
motor. That is a lot of big wire. Starters draw a lot of amps.
Unfortunately, Bob's wiring diagrams do not show how long all the runs are.
With my battery contactor, I do not have any big wires on the pilot's side
of the firewall. That is lighter and safer.
Indiana Larry, RV7 TipUp "SunSeeker"
The sincerest satisfactions in life come in doing and not dodging duty; in
meeting and solving problems, in facing facts, in being a dependable person.
- Richard L. Evans
----- Original Message -----
From: "David Carter" <dcarter@datarecall.net>
Subject: Re: AeroElectric-List: Simplification
> --> AeroElectric-List message posted by: "David Carter"
<dcarter@datarecall.net>
>
> Bob & OC,
>
> Thanks for the nice replies. Bob, your article on starters and circuit
> evolution is great.
>
> The only reason I "linked" manual batt sw and elim of starter contactor
was
> the issue of "killing the fat wire to the starter" - i.e., if the starter
> contactor is eliminated, and the fat wire is hot all the time the battery
sw
> is "on", and then, someday, the starter "runs on" after I release the
start
> button - some other way of killing that wire is needed - the manual
battery
> sw does that. Oh, so does a normal battery contactor. Oh, so, there is
no
> linkage. Either one works the same. Boy, I'm slow.
>
> I appreciate the issue of "stress" on the starter switch, i.e., it ought
not
> be subjected to current (inrush) that adversely shortens its life. The
> starter contactor is a good solution. But, with respect to that
> "evolutionary or evolved" refinement of the starter circuits - and I don't
> mean any disrespect for something that works and is in general practice -
> but adding a contactor to protect a switch from premature death is a
> work-around or substitute for getting a better switch. Now, as I say
that,
> I know that cars and non-OBAM aircraft operators aren't and can't,
> respectively, going to go put in a better switch, so the starter contactor
> becomes the elegantly simple and reasonable solution.
> - However, for us OBAMers, I'd rather get one of those heavy duty
> industrial grade "push to start" switches Bob mentioned in his reply.
Fits
> in with the idea of parts simplification and using better stuff than
> non-OBAM are permitted to use.
>
> I'll have to pick a starter that can be readily modified to unhook (or
cut)
> the solenoid coil's power lead from the "fat wire terminal" and have it
get
> its power from my industrial grade push button (Hey!! If all else fails I
> could use a knife switch & watch the big blue spark when I disconnect the
> starter - wouldn't that look cool? (or kooky?)
>
> Thanks, again for the great info and help "understanding the physics
> involved".
>
> David
>
> ----- Original Message -----
> From: "Robert L. Nuckolls, III" <rnuckolls@aeroelectric.com>
> To: <aeroelectric-list@matronics.com>
> Subject: Re: AeroElectric-List: Simplification
>
>
> > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> <rnuckolls@aeroelectric.com>
> >
> > At 10:59 PM 8/25/2004 -0500, you wrote:
> >
> > >--> AeroElectric-List message posted by: "David Carter"
> > ><dcarter@datarecall.net>
> > >
> > >OC,
> > >
> > >Thanks for the clarification. I'm assuming that aircraft starters
don't
> use
> > >the Bendix engagement system - too old and clunky?
> >
> > Some modern products do use the Bendix style pinion engagement
> > mechanism. It's relatively simple and works well as long as it's
> > not badly worn or insufficiently lubricated. But like batteries
> > in most airplanes, they don't get attention until they have been
> > misbehaving for some time.
> >
> > B&C chose not to go the Bendix route in a quest for the most
> > trouble free design with the longest service life we could deduce
> > at the time.
> >
> >
> > > The Z-diagrams show a
> > >starter "solenoid" - so that gadget is going to do the two things -
> provide
> > >current to motor and move the pinion gear to engage the flywheel.
> >
> > If you're talking about the circle perched right on top of the
> > "STARTER" symbol, yes. That is a combination electrical control
> > contactor and pinion gear engagement solenoid. See:
> >
> > http://www.aeroelectric.com/articles/strtctr.pdf
> >
> > Some of the earliest revisions to the Z-figures were driven by
> > a late discovery of the very high inrush currents demanded by
> > this style of starter contactor/solenoid mechanism. When installing
> > this starter on an airplane with a keyswitch, the solenoid would
> > be VERY hard on the starter contacts of the switch.
> >
> > Had a guy working for me about 15 years ago that had some brand
> > of small Japanese car. It wouldn't start one afternoon in the
> > parking lot of my business. We got out the meter and trouble shot
> > the system to discover that the starter switch in the key lock
> > was not closing. Upon disassembly of the switch, we found the
> > brass contacts of the starter circuit blackened and burned away.
> > He noted that the starter had been flaky for several months before
> > it quit. A new switch "fixed" it . . . an external contactor added
> > on as suggested in the Z-figures would have made the problem
> > go away for the lifetime of the car.
> >
> > This is what drove the recommendation for an external contactor
> > as shown in Figure 6 of the article and explained in the last
> > few paragraphs.
> >
> >
> > >So, looks like us two proponents of "simplification" are suggesting use
> of a
> > >manual battery switch which then allows the elimination of the "starter
> > >contactor" in the Z- drawings, i.e., #2awg fat wire goes from
downstream
> > >side of manual batt sw to fat wire terminal on starter solenoid
(instead
> of
> > >to upstream side of a starter contactor) and the push-to-start wire
goes
> to
> > >the starter solenoid coils instead of the "eliminated starter contactor
> > >coils".
> >
> > You have unrelated things tied together. The use of a manual battery
> > switch has no bearing on your style of starter or even if you have
> > a starter. Many aircraft have used manual switches in years past.
> > The Tri-Pacer in which I took dual instruction in 1961 had the
battery
> > mounted under the right seat. The battery master was a fat toggle
> > under the front edge of the seat. You can have a mechanical switch
> > for ANY battery installation on any airplane whether or not it has
> > a starter.
> >
> > You can use the starter's built in contactor/solenoid as shown
> > in Figure 6 of the article . . . just be aware of the special
> > stresses on what ever switch you use to energize the
> contactor/solenoid.
> > There are heavy duty push-buttons offered by many industrial
> > and heavy automotive supply houses that would be fine. I've not
> > conducted any tests on driving this bad-mamma contactor through
> > a fuse. You may find it necessary to use a 15A fuse and 14AWG
> > wire for your push-button circuit so that the inrush current doesn't
> > nuisance-trip the fuse.
> >
> > Parts count reduction is a good thing generally. Just be aware
> > that not all parts shown in the Z-figures were added purely for
> > the sake of some convenience. We've been trading off service life,
> > reliability, installed weight, wire routing and convenience
> > issues for decades. I'd like to think that the Z-figures
> > represent a distilled approach that has a considered
> > purpose for each component. Compared to the way we
> > can hose up the electrical system architecture in a biz jet,
> > the z-figures are stone simple. Efforts toward further
> > simplification should be supported by a through understanding
> > of the thought processes by which proposed "excess parts" were
> > included.
> >
> > Bob . . .
>
>
Message 17
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| Subject: | starter circuit simplification |
--> AeroElectric-List message posted by: <bakerocb@cox.net>
8/26/2004
Hello Dave Carter and Other Builders, I queried Tim Hedding of B&C regarding eliminating
the independent starter contactor in the starting circuit and using
just the solenoid on the starter itself to complete the electrical circuit and
move the pinion gear into and out of engagement. Below is Tims reply. I know
the attachments will not come through on the aeroelectric list, but if anyone
wants the attachments just email me and I will get them to you direct.
OC
-----------------------RESPONSE FROM TIM HEDDING FOLLOWS-------------
Owen, Let me offer the following points for consideration (these are specifically
with reference to our starters):
1) The starter solenoid houses two coils. They are common at the push-on tab on
the rear of the solenoid. The other end of one is grounded inside the solenoid
body. The other end of the second is tied to the starter motor output post and,
therefore, is grounded through the low resistance motor windings. When power
is applied to the push-on blade, the coils are both energized and both act
to extend the starter pinion. Once the starter pinion is extended fully, the motor
contacts in the base of the solenoid are closed, bypassing one of the coils
and energizing the starter motor. The remaining coil continues to keep the
pinion extended.
The "in-rush" current of the two parallel coils is about 30 amps. The residual
current during the start is about 10 amps. Most starter switches would be toast
very quickly if assigned to close on this much current. In fact, we have had
some who "knew better" and tried this only to buy a new starter because their
start switch welded closed. This is one reason why we wire the push-on tab permanently
to the starter input post and use a starter relay ("contactor") to complete
the circuit.
2) It is possible for either a starter solenoid to stick or a starter relay ("contactor")
to stick. Either, installed by itself could leave the starter running
until it is destroyed. This possibility is reduced when the relay and solenoid
are both used. In this case, the slowest contacts will be the ones stuck closed
and the other set will still be functional. If both are used and the relay
sticks, the master relay may be de-energized to kill the starter. If there
is no master relay (such as in our wiring diagram for aerobatic airplanes attached)
we provide a starter kill switch in the starter solenoid control circuit
to allow the pilot to interrupt the runaway starter. These normally-closed contacts
will not be damaged by the momentary 30 Amp in-rush but are capable of
interrupting the 10 Amp residual current.
While we're discussing this point, let me say that it is a good idea to install
a "Starter On Light" (drawing attached) that receives its power from the output
side of the starter relay. We've had some pilots who couldn't tell that the
starter was still running and did nothing to disengage the starter even when
they could have. These little devices are required by some foreign aviation authorities.
3) Though not practical in all airplanes, the best starter circuit wiring is usually
to place the master relay and starter relay close to the battery. The wiring
associated with these high current switches is large and not protected by
over-current devices. So, the wires are kept short and dressed carefully to prevent
uncontrollable fault currents. In this case, the wire from the starter
relay to the starter is not "hot" except when cranking. A short to an engine mount
or firewall at a penetration point during flight is inconsequential because
the wire is inert. If a starter relay is not used and the starter solenoid
is used as the controlling relay, this wire is hot continually and poses some
additional hazard or at least deserves extra attention to wire dress and pinion
points. A large hot cable such as this could also present an extra accident
hazard. Hopefully, we'll never have a bad landing incident that can violate the
engine compartment structure. In the unlikely event
that our "precious" goes cartwheeling down the runway, crushed or bent structures
could leave a very good ignition source in the engine compartment to set
off oil or fuel fumes.
Now, I know that different airframe construction materials, methods and architectures
affect the statements I've made above, but what would you recommend in
general concerning starter wiring, not knowing the intimate construction details
of each project that we deal with.
Tim Hedding,
E.E. at B&C
Message 18
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| Subject: | Re: Simplification |
--> AeroElectric-List message posted by: "David Carter" <dcarter@datarecall.net>
Larry,
Larry, the starter wiring thing we are talking is to run the "fat wire" 2awg
for starter motor current from downstream side of battery switch (manual) or
battery contactor (standard practice) to the "fat" terminal on the starter,
then mod the starter to feed the starter solenoid from a "heavy duty starter
switch" instead of staying tied to the post the fat wire goes on. Then run
a smaller wire that will handle 30 amps momentary, 10 amps continuous just
to power the starter solenoid coils (2 windings, as explained in Bob's
article & B&C's discussion in next e-mail). "Lectric Bob" made a
recommendation for size of such a wire to stand the inrush and short
duration steady state 10 amps - would not be the "motor current", just the
"solenoid current" - Bob's recent comment during this discussion was, "15A
fuse and 14AWG wire for your push-button circuit so that the inrush current
doesn't nuisance-trip the fuse."
David
----- Original Message -----
From: "LarryRobertHelming" <lhelming@sigecom.net>
Subject: Re: AeroElectric-List: Simplification
> --> AeroElectric-List message posted by: "LarryRobertHelming"
<lhelming@sigecom.net>
>
> David, the primary concern I have with running the big-o-boy start
> button/switch is that heavy and high amp wire runs all the way from its
> power source (the battery) to your panel switch and then on to the starter
> motor. That is a lot of big wire. Starters draw a lot of amps.
> Unfortunately, Bob's wiring diagrams do not show how long all the runs
are.
> With my battery contactor, I do not have any big wires on the pilot's side
> of the firewall. That is lighter and safer.
>
> Indiana Larry, RV7 TipUp "SunSeeker"
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