Today's Message Index:
----------------------
1. 05:07 AM - Time delay, flicker filter etc. (GTH)
2. 01:26 PM - Re: Amp meter jumps when transmitting (Henador Titzoff)
3. 01:34 PM - Re: Amp meter jumps when transmitting (Dj Merrill)
4. 02:30 PM - Re: Time delay, flicker filter etc. (Robert L. Nuckolls, III)
Message 1
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| Subject: | Time delay, flicker filter etc. |
Hi Bob and all,
It's been a long time since my last post on this knowledgeable list.
Our two battery / ABMM / Rotax 914 project has been flying for ten happy
years now, except for one little problem that has kept nagging at us
from the beginning.
The auxiliary battery management module (ABMM) works as advertised,
connecting and disconnecting the aux battery contactor following the
main bus voltage. But at idle, the voltage undergoes rapid fluctuations,
leading to frigthening contactor chattering fits.
As a workaround we ended connecting the aux battery manually.
I was wondering if an easy way of introducing time delay in the voltage
sensing side *or* actuating side of the ABMM could be devised ?
A time constant of 2 second would be adequate I suppose.
Could some variation of the fuel level flicker filter do ?
Thanks in advance for your suggestions, and keep on the good job !
Best regards,
--
Gilles
http://contrails.free.fr
Message 2
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| Subject: | Re: Amp meter jumps when transmitting |
You're right that I'm going down a road fraught with all sorts of relativel
y low risk items.- Just trying to explain why an open transmission line m
ight kill a transmitter that's otherwise designed to survive it.- I hope
my explanation of why the voltage could theoretically double at the transmi
tter helped explain to some how this phenomenon happens.=0A=0AHenador Titzo
ff=0A=0A=0A>________________________________=0A> From: "Robert L. Nuckolls,
III" <nuckolls.bob@aeroelectric.com>=0A>To: aeroelectric-list@matronics.co
m =0A>Sent: Sunday, April 27, 2014 10:50 PM=0A>Subject: Re: AeroElectric-Li
st: Amp meter jumps when transmitting=0A> =0A>=0A>--> AeroElectric-List mes
sage posted by: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
=0A>=0A>=0A>> >Manufactured lots vary from lot to lot, and some lots may sn
eak =0A>> through that do not meet specifications but work well until =0A>>
"something happens."- In >particular, this business of counterfeit =0A>>
parts has been plaguing manufacturing for at least two decades now.=0A>=0A
>- - Forgive me my friend but we're reaching WAAaaayyyy down into=0A>
- - the worry bucket with this line of reasoning. Once=0A>- - you o
pen that door . . . where do the caveats end?=0A>- - Cracked magneto ro
tors? Contaminated fuel? Bogus rivets?=0A>- - The world is indeed fraug
ht with risks. Nonetheless,=0A>- - the vast majority of misadventures i
n every=0A>- - venue have nothing to do with parts that fail=0A>- -
to meet published requirements. Adding such=0A>- - worries to the know
ledge base is potential misdirection=0A>- - of valuable attention from
======================0A>=0A>=0A>
=0A>=0A>=0A>
Message 3
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| Subject: | Re: Amp meter jumps when transmitting |
On 04/28/2014 04:22 PM, Henador Titzoff wrote:
> You're right that I'm going down a road fraught with all sorts of
> relatively low risk items. Just trying to explain why an open
> transmission line might kill a transmitter that's otherwise designed to
> survive it. I hope my explanation of why the voltage could
> theoretically double at the transmitter helped explain to some how this
> phenomenon happens.
>
> Henador Titzoff
Your explanation helped me, and matched my limited understanding of how
it works, as well as allowing me to learn more.
Thank you! :-)
-Dj
--
Dj Merrill - N1JOV - VP EAA Chapter 87
Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/
Glastar Flyer N866RH - http://deej.net/glastar/
Message 4
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| Subject: | Re: Time delay, flicker filter etc. |
>
>A time constant of 2 second would be adequate I suppose.
>Could some variation of the fuel level flicker filter do ?
>
>Thanks in advance for your suggestions, and keep on the good job
Referring to the assembly details in . . .
http://tinyurl.com/nxmo3us
That comparator only has about 0.5% hysteresis . . .
try reducing the value of R108 down to 100K
which will raise the hysteresis by a factor of ~5x
Bob . . .
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