Today's Message Index:
----------------------
1. 06:44 AM - Wire identification (Robert L. Nuckolls, III)
2. 06:49 AM - Re: Re: IVO Prop Motor Current Limiter and Electronic CB (Robert L. Nuckolls, III)
3. 07:10 AM - Re: Re: IVO Prop Motor Current Limiter and Electronic CB (Robert L. Nuckolls, III)
4. 06:16 PM - Re: IVO Prop Motor Current Limiter and Electronic CB (Dennis & Anne Glaeser)
5. 06:54 PM - Re: Re: IVO Prop Motor Current Limiter and Electronic CB (Robert L. Nuckolls, III)
6. 07:14 PM - Re: Re: IVO Prop Motor Current Limiter and Electron ic CB (n801bh@netzero.com)
7. 08:51 PM - Electric Boost Pump & Primer Switching (John Volkober)
Message 1
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| Subject: | Wire identification |
Comments/Questions: On the Power Distribution diagrams it doesn't
show any special color for various wires.
Just wondered, there are so many wires in even a small like my RV-4,
should there be different colors for certain connections.
I know RED is for power and BLACK is for ground but are other colors
generally used for other connections or are all wires just considered
either power or ground?
The notion of marking wires with either colors or
legends goes to the future task of troubleshooting.
When you're installing wires, you pretty much know
where they go and what they do. Further, there
are so few wires total in a small aircraft that
spending the $time$ to add any special identification
to a wire adds little value in the future.
Finally, wire is not cheap but buying in full
spools or lots of 100' can save you some money.
You don't want to have long spools of many
colors that leaves you with a lot of left over
wire at the end of your project.
Suggest you go with what ever color (usually
white) that makes sense economically. If you
want to label some or all of them, consider
paper labels held on the ends of the wire runs
with clear heatshrink like . . .
http://aeroelectric.com/Pictures/Wiring_Technique/Wire_Marking.jpg
Bob . . .
Message 2
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| Subject: | Re: RE: IVO Prop Motor Current Limiter and Electronic |
CB
At 10:20 PM 5/8/2010, you wrote:
<glaesers@wideopenwest.com>
I made the original circuit that Bob posted. I got all the parts from
DigiKey, including the IRFP 3703.
I was finally able to test that circuit today. It worked exactly as
predicted. With only the 0.1 ohm resistor, the current was limited to about
6 amps. This did not allow the motor to go as far as desired. So I added the
parallel 0.5 ohm resistors one at a time. With both in place, it allows a
bit over 8 amps, which is where the motor just starts to strain. This is
also about the same place where the reed switch triggers.
The mosfet does get rather warm, but only if the switch is held longer than
normal.
I've had a lot of folks become concerned with transistors
that got "rather warm" but without puting some form of
instrumentation on the device and then accounting for
thermal resistances in the heat-energy transfer path,
"rather warm" is a rather loose quantification term.
There are instances where the surface temperature of
a power device can get up to "sizzle-spit" temperatures
and still be within operating limits. So if your finger-test
of the device did not send you looking for the burn
ointment, then there's a high probability that the
transistor as installed and operated is going to be
okay . . .
I also plan to build the Electronic CB circuit. When it was published, Bob's
said to wait until others had a chance to review and comment before
building, so I haven't begun that process yet.
Go ahead an 'brass-board' it if you can. I'm still to tied
up with table saws and paint brushes to spend time at
the bench.
Do you have access to a 'scope? It would be interesting
to fine-tune/verify the value of the capacitor to make the
circuit trip in 200-500 milliseconds after the
green light comes on.
Thanks for your help in the development effort.
Bob . . .
Message 3
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| Subject: | Re: RE: IVO Prop Motor Current Limiter and Electronic |
CB
>I was finally able to test that circuit today. It worked exactly as
>predicted. With only the 0.1 ohm resistor, the current was limited to about
>6 amps. This did not allow the motor to go as far as desired. So I added the
>parallel 0.5 ohm resistors one at a time. With both in place, it allows a
>bit over 8 amps, which is where the motor just starts to strain. This is
>also about the same place where the reed switch triggers.
Hmmmm . . . for the final configuration you'll probably want
to increase the current limit on up to 10A. Without knowing
the modulus of elasticity of the prop materials with respect
to temperature, you don't want to loose pitch-stroke because
the current limit it set too low. So paralleling the .1 ohm
with .2 ohms will produce a total of 1/(1/0.2 + 1/0.1)= 0.066
ohms which should boost the limit to just over 10A.
Adding the 200-500 millisecond trip over ride should allow
you to flirt at the edges of the 10 C/B value without
tripping it.
Bob . . .
Message 4
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| Subject: | RE: IVO Prop Motor Current Limiter and Electronic CB |
The mosfet does get rather warm, but only if the switch is held longer than
normal.
I've had a lot of folks become concerned with transistors
that got "rather warm" but without putting some form of
instrumentation on the device and then accounting for
thermal resistances in the heat-energy transfer path,
"rather warm" is a rather loose quantification term.
There are instances where the surface temperature of
a power device can get up to "sizzle-spit" temperatures
and still be within operating limits. So if your finger-test
of the device did not send you looking for the burn
ointment, then there's a high probability that the
transistor as installed and operated is going to be
okay . . .
----> I didn't think to measure the mofset temp, but it definitely didn't
get 'sizzle-spit' hot in my tests. I'm sure it could if the switch
were
held long enough. I'll measure temps at my next opportunity.
-----
I also plan to build the Electronic CB circuit. When it was published, Bob's
said to wait until others had a chance to review and comment before
building, so I haven't begun that process yet.
Go ahead an 'brass-board' it if you can. I'm still to tied
up with table saws and paint brushes to spend time at
the bench.
Do you have access to a 'scope? It would be interesting
to fine-tune/verify the value of the capacitor to make the
circuit trip in 200-500 milliseconds after the
green light comes on.
----> I will do that, but it will be a little while before I can get to it.
Work and other commitments definitely get in the way of the fun
stuff.
I don't have a 'scope, but may be able to find one in my EAA
chapter.
----
Thanks for your help in the development effort.
Bob . . .
----> I'm the one who is the recipient of YOUR work :-)
Dennis
Message 5
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| Subject: | Re: RE: IVO Prop Motor Current Limiter and Electronic |
CB
At 08:13 PM 5/9/2010, you wrote:
><glaesers@wideopenwest.com>
>
> Thanks for your help in the development effort.
>
> Bob . . .
>
>----> I'm the one who is the recipient of YOUR work :-)
>
> Dennis
We all have a part to play. I can plant seeds but may not
have the time to explore their value. If folks like you
can pick up the ball and advance it down-field, then
value has been added. Ultimately, we wish that others
will benefit from the sum total of everyone's start-
up efforts.
THAT is how the gathering of simple-ideas gets
vetted as a recipe for success. Folks on the List
may recall numerous conversations in the past where a
particular design philosophy was the target of vociferous
bashing . . . while thousands of examples had been
flying and performing as expected for two decades.
What we do here may flop. It may be a ho-hum success.
It may provide the idea-seeds for yet another quantum
jump in capability or utility. But seeds never planted,
nurtured and harvested will never reveal their value.
Bob . . .
Message 6
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| Subject: | Re: RE: IVO Prop Motor Current Limiter and Electron |
ic CB
Thanks guys for experimenting in this area.... I have been through 1 Ivo
motor so far and the current one is showing its age now... I am pretty
anal about taking care not to drive the motor to its stall limit by usin
g my ammeter to show increased amp draw, but this is kinda hard to do wi
th my 80 amp alt keeping up with the load and masking the higher draw wh
en stalled, or at least approaching it. The 'extra' noise from the V-8 u
p front doesn't help either. <G>.
Tailwinds all..............
do not archive
Ben Haas
N801BH
www.haaspowerair.com
---------- Original Message ----------
From: "Dennis & Anne Glaeser" <glaesers@wideopenwest.com>
Subject: AeroElectric-List: RE: IVO Prop Motor Current Limiter and Elect
ronic CB
rs@wideopenwest.com>
The mosfet does get rather warm, but only if the switch is held longer t
han
normal.
I've had a lot of folks become concerned with transistors
that got "rather warm" but without putting some form of
instrumentation on the device and then accounting for
thermal resistances in the heat-energy transfer path,
"rather warm" is a rather loose quantification term.
There are instances where the surface temperature of
a power device can get up to "sizzle-spit" temperatures
and still be within operating limits. So if your finger-test
of the device did not send you looking for the burn
ointment, then there's a high probability that the
transistor as installed and operated is going to be
okay . . .
----> I didn't think to measure the mofset temp, but it definitely didn'
t
get 'sizzle-spit' hot in my tests. I'm sure it could if the switch
were
held long enough. I'll measure temps at my next opportunity.
-----
I also plan to build the Electronic CB circuit. When it was published, B
ob's
said to wait until others had a chance to review and comment before
building, so I haven't begun that process yet.
Go ahead an 'brass-board' it if you can. I'm still to tied
up with table saws and paint brushes to spend time at
the bench.
Do you have access to a 'scope? It would be interesting
to fine-tune/verify the value of the capacitor to make the
circuit trip in 200-500 milliseconds after the
green light comes on.
----> I will do that, but it will be a little while before I can get to
it.
Work and other commitments definitely get in the way of the fun
stuff.
I don't have a 'scope, but may be able to find one in my EAA
chapter.
----
Thanks for your help in the development effort.
Bob . . .
----> I'm the one who is the recipient of YOUR work :-)
Dennis
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Message 7
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| Subject: | Electric Boost Pump & Primer Switching |
This is my first post, so here we go.
I want to have a single switch that controls my electric fuel pump and
also
allows me to activate my primer solenoid. The diagram below is my idea
of
on how this should work. I am using a S700-51 switch. In the first
position, the electric fuel, pump in off. In the second position, the
fuel
pump is on. In the third position, a momentary position, both the fuel
pump
and the primer solenoid are on activating the primer. Will this work?
Is
there a another approach I should consider?
John Volkober
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