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Thread: Electrical Problems

  1. #1
    Orbiting Earth Orbiting Earth sjcote's Avatar
    Join Date
    Jul 2004
    Location
    Springfield, Massachusetts
    Posts
    1,178

    Electrical Problems

    This may have gone out earlier today.but my system tells me it didn't. Sorry
    if it is a repeat.



    Hi all,



    We have a really annoying electrical problem and I have not found quite the
    same thing on the site. Hope you can advise me.



    At our Annual in Feb, we replaced the old battery (with a Gill-35). After
    getting her back she seemed to run fine (took her to Brian's Maine Fly-In).

    However, at about 10 hours post Annual, we began to get sudden deep
    discharge readings (-15 amps); usually in flight.



    Several times we would get a good start, with a heavy initial charge to
    catch up from the starter as normal, and a fine reading on run-up. But in
    the air it would slowly begin to sag. Shedding load and recycling the Alt
    and Master switches did nothing. But adding something (like landing light)
    would pull it waaay down and turning the light out didn't bring it back.



    So, OK, we changed the Voltage Regulator. She worked fine when picked up.
    Three flight hours later, same thing. This time we checked again for loose,
    corroded cables and connections; for bad circuit breakers and switches.
    Nothing. So we changed the alternator (we couldn't make it fail on the test
    bench but it was 20 years old so.). Picked her up on Friday and flew her
    hard for over two hours. Turned on everything we could find in the plane.she
    looked just fine!



    An hour later my partner flies down to Hartford (20 min) and she's fine.
    Comes back out to return.same problem. This time right from start up. On
    Saturday I started her and ran her for a while. No good initial charge and
    any load would pull the amps down.



    There are only two components left in the system: battery and ammeter. We
    are trained that when something goes suddenly silent in the air, to "undo"
    the last thing we did (ie: go back to that other tank). Thinking that way,
    is it possible that this brand new battery, which seems to test fine, goes
    bad when being charged?



    And the ammeter (the 30 year old original, I admit) is so stone simple that
    I cannot figure how it can fail the whole system.



    Thanks for any advice,

    Steve Cote

    N1958L

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  2. #2
    You might want to check that the cables/connectors are clear of the box (ground) by an adequate margin. If not they might get close enough in flight to touch.

    sometimes it's the littlest things...

  3. #3

    Electrical Problems

    Not sure how old you plane is but I had an ALMOST IDENTICAL problem with
    my A23-19 which is 1964 vintage.

    In the end discovered a strange looking component bolted across the
    master relay hidden in the void behind the battery compartment. After a
    lot of digging found out that it was some sort of interference
    suppressor to stop de-energisation potentials from the master relay from
    frying the electronics. Originally some sort of piezo capacitor, After A
    GREAT DEAL of digging discovered that this had been superceeded by dirt
    cheap IN1004 diode in the late 60s. For the life of me I cant remember
    the technical terms and my maintenance place is shut so cant access the
    records but basically look for that component and disconnect it then
    replace with a 10c Radio Shack diode! I think there is a Beach Service
    bulletin for this somewhere (this was all a couple of years ago amid
    traumas of installing a new panel).

    Just come to me. I think the device was something called a Varactor.
    Might be wrong.

    It is shown on the early electrical circuit diagrams in the workshop
    manuals on the BAC web site.

    I remember this was a humdinger to track down after most of the same
    stages as you have gone through.

    -Allan Palmer
    Anaesthetist, Brisbane, Australia
    MSN: allan@palmer.net.au


    > -----Original Message-----
    > From: bac-mail-bounces@beechaeroclub.org
    > [mailto:bac-mail-bounces@beechaeroclub.org] On Behalf Of Stephen Cote
    > Sent: Monday, May 08, 2006 9:20 AM
    > To: 'BAC Mail'
    > Subject: [BAC-Mail] Electrical Problems
    _______________________________________________
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  4. #4
    mike at rellihan.com
    Guest

    Electrical Problems

    It is called a 'Klipvolt suppressor'. If you do a BAC search on Klipvolt',
    you'll find all the info you need, including the SB. I posted the info a
    year ago.


    -----Original Message-----
    From: bac-mail-bounces@beechaeroclub.org
    [mailto:bac-mail-bounces@beechaeroclub.org] On Behalf Of Allan Palmer
    Sent: Monday, May 08, 2006 4:59 AM
    To: Stephen Cote
    Cc: bac-mail@beechaeroclub.org
    Subject: RE: [BAC-Mail] Electrical Problems

    Not sure how old you plane is but I had an ALMOST IDENTICAL problem with
    my A23-19 which is 1964 vintage.

    In the end discovered a strange looking component bolted across the
    master relay hidden in the void behind the battery compartment. After a
    lot of digging found out that it was some sort of interference
    suppressor to stop de-energisation potentials from the master relay from
    frying the electronics. Originally some sort of piezo capacitor, After A
    GREAT DEAL of digging discovered that this had been superceeded by dirt
    cheap IN1004 diode in the late 60s. For the life of me I cant remember
    the technical terms and my maintenance place is shut so cant access the
    records but basically look for that component and disconnect it then
    replace with a 10c Radio Shack diode! I think there is a Beach Service
    bulletin for this somewhere (this was all a couple of years ago amid
    traumas of installing a new panel).

    Just come to me. I think the device was something called a Varactor.
    Might be wrong.

    It is shown on the early electrical circuit diagrams in the workshop
    manuals on the BAC web site.

    I remember this was a humdinger to track down after most of the same
    stages as you have gone through.

    -Allan Palmer
    Anaesthetist, Brisbane, Australia
    MSN: allan@palmer.net.au


    > -----Original Message-----
    > From: bac-mail-bounces@beechaeroclub.org
    > [mailto:bac-mail-bounces@beechaeroclub.org] On Behalf Of Stephen Cote
    > Sent: Monday, May 08, 2006 9:20 AM
    > To: 'BAC Mail'
    > Subject: [BAC-Mail] Electrical Problems
    _______________________________________________
    BAC-Mail mailing list
    BAC-Mail@beechaeroclub.org
    http://www.beechaeroclub.org/mailman/listinfo/bac-mail



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  5. #5

    Electrical Problems

    Sounds like 'klingons'..was a big fan of Star Trek..

    In a message dated 5/8/2006 9:02:25 A.M. Eastern Standard Time,
    mike@rellihan.com writes:

    It is called a 'Klipvolt suppressor'. If you do a BAC search on Klipvolt',
    you'll find all the info you need, including the SB. I posted the info a
    year ago.


    -----Original Message-----
    From: bac-mail-bounces@beechaeroclub.org
    [mailto:bac-mail-bounces@beechaeroclub.org] On Behalf Of Allan Palmer
    Sent: Monday, May 08, 2006 4:59 AM
    To: Stephen Cote
    Cc: bac-mail@beechaeroclub.org
    Subject: RE: [BAC-Mail] Electrical Problems

    Not sure how old you plane is but I had an ALMOST IDENTICAL problem with
    my A23-19 which is 1964 vintage.

    In the end discovered a strange looking component bolted across the
    master relay hidden in the void behind the battery compartment. After a
    lot of digging found out that it was some sort of interference
    suppressor to stop de-energisation potentials from the master relay from
    frying the electronics. Originally some sort of piezo capacitor, After A
    GREAT DEAL of digging discovered that this had been superceeded by dirt
    cheap IN1004 diode in the late 60s. For the life of me I cant remember
    the technical terms and my maintenance place is shut so cant access the
    records but basically look for that component and disconnect it then
    replace with a 10c Radio Shack diode! I think there is a Beach Service
    bulletin for this somewhere (this was all a couple of years ago amid
    traumas of installing a new panel).

    Just come to me. I think the device was something called a Varactor.
    Might be wrong.

    It is shown on the early electrical circuit diagrams in the workshop
    manuals on the BAC web site.

    I remember this was a humdinger to track down after most of the same
    stages as you have gone through.

    -Allan Palmer
    Anaesthetist, Brisbane, Australia
    MSN: allan@palmer.net.au




    _______________________________________________
    BAC-Mail mailing list
    BAC-Mail@beechaeroclub.org
    http://www.beechaeroclub.org/mailman/listinfo/bac-mail

  6. #6

    Electrical Problems

    >
    > Just come to me. I think the device was something called a Varactor.
    > Might be wrong.
    >
    *** More likely a "Varistor". A varactor is a voltage-controlled
    capacitor. Used for tuning radios. A varistor, OTOH, is a device that
    has a high resistance at low voltages, and a lower resistance at higher
    voltages. So when a voltage spike happens, the varistor shorts it out.

    It's a characteristic of inductors ( such as relay coils ) that they
    want to maintain a constant current through them. When you turn off the
    power to an inductor, it will produce a large reverse-voltage spike to
    attempt to maintain its current. A varistor will short out the spike.
    Somewhat. Heating itself up in the process, because it's a resistor.

    However, a silicon diode can do the job better and cheaper, taking
    advantage of the fact that the spike produced by the inductor is REVERSE
    VOLTAGE. And it "shorts" the reverse spike all the way down to .6 volts,
    which is the forward potential of the diode. The two good things here are
    that .6V is not likely to damage anything up the line, and that the ohmic
    heating of the diode is small ( Power = current times voltage ).

    And by the late 60's, industry was capable of making VERY cheap &
    reliable silicon diodes.

    - Jerry Kaidor ( jerry@tr2.com )




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