Today's Message Index:
----------------------
1. 09:31 AM - (david caswell)
2. 09:39 AM - (david caswell)
3. 09:59 AM - current limiting warning lights for EI instruments (Brian Lloyd)
4. 03:16 PM - Re: current limiting warning lights for EI instruments (david caswell)
5. 04:01 PM - Z-13 modifications for 35 amp PM Alternator (David Carter)
6. 04:56 PM - Re: current limiting warning lights for EI instruments (Brian Lloyd)
7. 06:19 PM - Cleveland Crimp Tool Mystery Solved .NOT . (Robert L. Nuckolls, III)
8. 09:51 PM - Pitot Heat wiring question.... (jacklockamy)
Message 1
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1.16 MISSING_SUBJECT Missing Subject": header@matronics.com
--> AeroElectric-List message posted by: david caswell <davidbcaswell@yahoo.com>
I am in process of installing International Electronics iInstruments and am connecting
wiring to the panel mounted warning lights (B&C) from the instruments
(EGT/CHT and Fuel). The installation instructions specify that current be no
higher that 1/10 amp on the FUEL, and 2/10 amp on the EGT. The signal from both
instruments creates a ground. What is the best way to limit the current from
the buss to these lights? A resistor in series? And is the R=E/I the way to
calculate the size of this resistor? (14/.020=700) ? 700 ohm resistor? I am also
wiring a "starter engaged" warning light from the starter "I" terminal. Does
this lead need a resistor before it gets to the warning light?
Any help would be greatly appreciated. Thank you.
David
Message 2
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1.16 MISSING_SUBJECT Missing Subject": header@matronics.com
--> AeroElectric-List message posted by: david caswell <davidbcaswell@yahoo.com>
I am looking for a grip mounted "slide switch" for my flaps. The only one I've located is Otto Controls http://ottoeng.com/control/slideswitch.htm. The price is $180. I think I remember reading about one that was priced more reasonably. Does anyone have a source for this item?
THANK YOU
Message 3
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| Subject: | current limiting warning lights for EI instruments |
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
> --> AeroElectric-List message posted by: david caswell
> <davidbcaswell@yahoo.com>
>
> I am in process of installing International Electronics iInstruments
> and am connecting wiring to the panel mounted warning lights (B&C)
> from the instruments (EGT/CHT and Fuel). The installation
> instructions specify that current be no higher that 1/10 amp on the
> FUEL, and 2/10 amp on the EGT. The signal from both instruments
> creates a ground. What is the best way to limit the current from the
> buss to these lights? A resistor in series?
Yes.
> And is the R=E/I the way to calculate the size of this resistor?
> (14/.020=700) ? 700 ohm resistor?
You are correct in how you calculate the resistance but you neglected
to account for the resistance in the bulb itself. You also didn't
indicate whether you plan to use incandescent light indicators or LED
indicators.
Also, 2/10 amp is 0.2A, not 0.020A. The latter is 20mA, just about
right for an LED.
If the indicator is an incandescent bulb you just select the bulb to
have the proper current draw. If it is a low-voltage bulb, perhaps
6.3V, then you need a dropping resistor in series to put the proper
voltage drop across the bulb. Likewise for an LED.
> I am also wiring a "starter engaged" warning light from the starter
> "I" terminal. Does this lead need a resistor before it gets to the
> warning light?
It depends on the type of bulb you are using. Can you provide more
detail?
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
+1.340.998.9447 St. Thomas, VI 00802
Message 4
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| Subject: | Re: current limiting warning lights for EI instruments |
--> AeroElectric-List message posted by: david caswell <davidbcaswell@yahoo.com>
Brian Lloyd <brianl@lloyd.com> wrote:
--> AeroElectric-List message posted by: Brian Lloyd
> --> AeroElectric-List message posted by: david caswell
>
>
> I am in process of installing International Electronics iInstruments
> and am connecting wiring to the panel mounted warning lights (B&C)
> from the instruments (EGT/CHT and Fuel). The installation
> instructions specify that current be no higher that 1/10 amp on the
> FUEL, and 2/10 amp on the EGT. The signal from both instruments
> creates a ground. What is the best way to limit the current from the
> buss to these lights? A resistor in series?
Yes.
> And is the R=E/I the way to calculate the size of this resistor?
> (14/.020=700) ? 700 ohm resistor?
You are correct in how you calculate the resistance but you neglected
to account for the resistance in the bulb itself. You also didn't
indicate whether you plan to use incandescent light indicators or LED
indicators.
Also, 2/10 amp is 0.2A, not 0.020A. The latter is 20mA, just about
right for an LED.
If the indicator is an incandescent bulb you just select the bulb to
have the proper current draw. If it is a low-voltage bulb, perhaps
6.3V, then you need a dropping resistor in series to put the proper
voltage drop across the bulb. Likewise for an LED.
> I am also wiring a "starter engaged" warning light from the starter
> "I" terminal. Does this lead need a resistor before it gets to the
> warning light?
It depends on the type of bulb you are using. Can you provide more
detail?
The warning lights are from the B & C Specialties http://www.bandc.biz/cgi-bin/ez-catalog/cat_display.cgi?10X358218#s888-1-2. I really didn't look at the bulbs, or even if they had bulbs. I assume they are incandescent. I will look tomorrow. Thanks for direction.
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
+1.340.998.9447 St. Thomas, VI 00802
Message 5
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| Subject: | Z-13 modifications for 35 amp PM Alternator |
--> AeroElectric-List message posted by: "David Carter" <dcarter@datarecall.net>
After the recent exchange of ideas on "simplification", and an examination
of relays and contactors available for use to shutdown the PM alternator,
and because of a concern expressed by one fellow of a short in the voltage
regulator and nothing between the alternator and the VR to protect the wires
or the VR, here are two things I think I need to do to in adapting Z-13 to
my specific system:
1. Relay to connect/disconnect the alternator & VR from the aircraft
electrical busses (as shown in ORIGINAL - unmodified - Z-13, not the stuff I
put on my website the other night):
- Since the SD-8 (8 amp device) is being replaced with a 35 amp John
Deere PM alternator as my only alternator, the S-704-1 relay, being good for
only 20 amps continuous, will be replaced by, for example, a Bosch High
Capacity (50 amps) relay, WayTek p/n 75002, Bosch p/n 0 332 019 110, 12v,
SPST, 50 amps Normally Open, four terminals (2 for coil, 2 for power) ,
bracket mount $3.53 + $0.27 for 75281 connector shell (vs $10 for S-704-1
from B and C).
- Does it look like I have a reasonable amount of "head room" (if that
is the correct term) for the relay, it being rated at 50 amps (DC) and my
alternator being rated at 35 amps ( but putting out who-knows-what into the
regulator, which has to suck up and dissipate all the unused electrons)?
2. Protect the wires between "dynamo" and VR with in-line fuses of ______
amp capacity:
- Since the "dynamo" is putting out unregulated voltage and alternating
current which is directly proportional to rpm of alternator, and independent
of what my aircraft systems (other than the VR) are consuming, and given
that the alternator is "rated at" 35 amps and I won't have any more than
that "on-line" at any time, then how do I design appropriate protection for
the 2 wires going to the VR?
- What is the nature of the current flow in the 2 wires when the
airplane is actually consuming 35 amps?
. . . -- I.e., at a given engine and alternator rpm at cruise, and
actual electrical consumption by stuff in the airplane actually turned on
and consuming 35 amps of electricity, what kind and rating of fuse do I need
in each of the 2 wires between the alternator and VR? 17.5 amps in each
wire, or 35 amps in each wire?
... -- Whichever, then how much "head room" should I allow for, i.e.,
if each wire is going to be designed for a normal current of 35 amps, then
revised Fig 8-4 says I might consider, for 35 deg C/63 deg F rise, using
"13.5 awg" (pick next larger, 12 awg, which is what Z-13 shows for use with
the 8 amp dynamo). If max current is only 17.5 amps, then could use 18 or
16 awg for 35 deg C rise. Z-13 shows using 12 awg.
...-- If want to allow only a 10 deg C rise (18 deg F) in the already
warm engine compartment, then Fig 8-4 suggests 8 awg for 35 amps each wire
or 14 awg for 17.5 amps in each wire.
- The bigger question - peculiar to PM alternators (dynamos) - is this:
If alternator output is proportional to rpm, only, not to what the aircraft
(other than the VR) is consuming, it looks like 1) I need a graph (or need
to make my own) of "current vs rpm" and 2) if I size my pulleys for the
alternator so I get enough current to run my "night IFR, descent to landing
phase of flight" load at some reduced descent power, then when I am cruising
at higher rpm, or taking off and climbing (or racing?) at full throttle,
then what is the current output of the PM alternator?
Whatever I'm not consuming out of the VR is going to be consumed by the VR
itself to generate heat - correct?
If so, then I need to size my wires from alternator to VR and fuse them to
protect against my "max engine/alternator rpm" condition. I don't yet know
what that is. How can I estimate it?
Looks like I need an AC ammeter in my aircraft so I'll know what the
alternator is doing. Is there such a device available to adapt to my OBAM
aircraft? I assume it will be different from the DC loadmeters and ammeters
we normally discuss on this list.
David
Message 6
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| Subject: | Re: current limiting warning lights for EI instruments |
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
> --> AeroElectric-List message posted by: david caswell
> <davidbcaswell@yahoo.com>
>
> The warning lights are from the B & C Specialties
> http://www.bandc.biz/cgi-bin/ez-catalog/cat_display.cgi?
> 10X358218#s888-1-2. I really didn't look at the bulbs, or even if
> they had bulbs. I assume they are incandescent. I will look
> tomorrow. Thanks for direction.
I am familiar with the assembly as the same one came with my LR-3
regulator. I don't remember the current drain either but I suspect it
would work fine directly with the EI instruments without any extra
hardware.
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
+1.340.998.9447 St. Thomas, VI 00802
Message 7
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| Subject: | Cleveland Crimp Tool Mystery Solved .NOT . |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
At 06:58 AM 9/3/2004 -0700, you wrote:
>--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
>
>
>----- Original Message -----
>From: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
>To: <aeroelectric-list@matronics.com>
>Subject: AeroElectric-List: Re: Cleveland Crimp Tool Mystery Solved . . .
>
>snip>>Unlike the tools B&C sells with symmetrical dies, >>>>
>
>Bob, I simply do not understand how the above symetrical die tool will
>properly crimp a terminal.
>
>Sure it can crimp the conductor to the needed gas tight crimp.
>
>However the insulation grip REQUIRES a different shape die to properly crimp
>the insulation with the metal sleeve that is a part of the PIDG terminal.
>The need is to crimp the sleeve on both sides of the wire with minimal
>crimping on top of the wire.
>
>After this thread started I went and looked again at my various crimpers. I
>have crimpers designed for the vinyl insulation terminals commonly sold in
>auto stores as well as AMP crimpers designed for PIDG terminals. Both types
>work well on the terminals they were designed for. ALL have different die
>shapes for the two parts of the crimp.
>
>Insulation support is part of the terminal design and a proper insulation
>crimp is needed in my opinion (as well as the industry it seems). Simply
>looking at the result of a proper crimp shows the inner metal sleeve of the
>terminal nicely shaped around the wire insulation without insulation
>distortion and nearly 360 degree support. The excess material results in a
>end view much like a round fush acft with mid stubby wings =O=.
>
>Proper insulation support on the wire side of the crimp is critical to wire
>to terminal long term resistance to failure.
I was skeptical too when I evaluated the sample of the low-cost
tool that lunched my parts/tools business a few years ago. Up to that
time, I'd used nothing but the $high$ professional tools from AMP and
installed the occasional terminal with the hardware store, stamped
sheet metal tools.
Crimps produced by the $40 tool were, as you've noted, decidedly
different that the "pro" tools. See:
http://www.aeroelectric.com/articles/CrimpTools/H.jpg
This picture shows a 22-18 PIDG closed down on a 22AWG
Tefzel wire (22759/16-22) with the "pro" tool and the "el-cheapo"
tool. Yup, the one on the right is more purty . . . but is
it all that different in performance? If we're trying to
relieve stress on the transition from stranded to solid
conductors at the crimp, all that's required is some support
of the wire. As it was explained to me some years ago, support
means anything from just shy of actually touching the insulation
(meaning that a couple thousanths gap is not evil) to actually
putting some crush on the insulation. Recall that we're crushing
the bejabbers out of the stands to get gas tight conduction - there's
no prohibition for putting some crush on the insulation
in the support grip as well. The symmetrical die tool puts
considerable mash on an 18AWG insulation in the red
PIDG terminal. While the well-molded insulation grip produced
by the $high$ is pleasing to look at, there's no foundation
in physics that says it outperforms its ugly cousins.
The wire grip produced by the Cleveland tool in
http://www.aeroelectric.com/Pictures/CLEVELAND66A.jpg
just barely contacts the insulation . . . since this is
the smallest PVC wire that would be used with that terminal,
I'll suggest the insulation grip will be adequate for
22-18 AWG PVC. On the other hand, the grip shown in
http://www.aeroelectric.com/Pictures/CLEVELAND65A.jpg
is WAAAaaayyyy too loose. Dave tells us that a replacement for
this tool measures about 0.010" smaller in the wire grip
opening . . . given the breezeway I observe in the picture
above, I am skeptical that 0.010" more closure on the die
will close sufficiently on 22769/16-22 Tefzel.
If I had my druthers, everyone building their own airplane
would have AMP tools to install AMP terminals throughout.
However, that's not possible so our goal as advisors is to
gage the impact of various compromises. I judge that the Cleveland
tool I tested is NOT a compromise but completely off the
mark for installing PIDG on 22759/16 wire. However, the
$low$, symmetrical die tool as tested several years ago
produces consistent, and adequate if somewhat ugly crimps
that will perform well.
Just for grins, I went to the bench and put a red PIDG
on Tefzel wire with a hardware store crimp tool. This tool
produced the predictably funky results illustrated in
http://www.aeroelectric.com/Pictures/90.jpg
and
http://www.aeroelectric.com/Pictures/92.jpg
Ugly? Yes.
Cross section through the wire grip?
Gas tight.
Pull test? Over 30 pounds . . . wire failed
leaving strands captured in wire grip of
terminal.
Insulation grip? Again, not very pretty
but I see no reason in physics to suspect
it's any less adequate to the task than
other tools I have ranging from $40 to $600.
Bob . . .
---
Message 8
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| Subject: | Pitot Heat wiring question.... |
--> AeroElectric-List message posted by: "jacklockamy" <jacklockamy@verizon.net>
Here's one that has me 'stumped'......
Building an RV-7A. Wings are on... I'm at the airport wiring the wings/wingtips.
I hook up the Pitot (Gretz) Heat wire, turn ON the battery side of the Cessna
type Split Master switch I have installed... no heat. Check to make sure
I'm getting 12v to the pitot mast +wiring... yep. Then I turn the ALTERNATOR
side of the split master ON in conjunction with the Battery side of the switch...
then I get heat at the Pitot mast. And when I say "heat".. I mean "HEAT!!!".
My Gretz heated pitot tube gets so hot it will burn you if you aren't careful.
What is going on here? I have a master bus (where the pitot + is connected) in
addition to an Avionics bus. Everthing else is working 'normally'..... Just
can't figure out why the pitot mast doesn't get hot until the Alternator side
of the split master is turned ON with the Battery side turned ON. All other items
on the Master bus get "hot' when I turn the battery side of the split switch
ON. Does this make sense? Why doesn't the mast get hot with just the Battery
side of the switch on? I don't have an engine mounted (still at the re-builders)
thus I have no alternator hooked up either.......
It works, but I just don't understand what is going on....
Thanks in advance,
Jack Lockamy
Camarillo, CA
BTW.... I was lucky enough to purchase my chromed Gretz heated Pitot tube, mounting
bracket, etc. for $50! Another fellow was parting out his RV and I snagged
it!
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