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    Ideas For Design 1981 - 1995

    Uploaded by

    Alessandro Vinassa
    The document describes an issue with a 400 Hz generator detecting missing power cycles and shutting down improperly. A simple interface card was built with optocouplers to monitor the 400 Hz power from the generator and send the signal to a PC. This allowed logging of the missing cycles to better understand the intermittent generator failure issues, which varied from 1 to 5 missing cycles and did not always trigger an automatic shutdown.

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    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd

    Ideas For Design 1981 - 1995

    Uploaded by

    Alessandro Vinassa
    17 views165 pages
    The document describes an issue with a 400 Hz generator detecting missing power cycles and shutting down improperly. A simple interface card was built with optocouplers to monitor the 400 Hz power from the generator and send the signal to a PC. This allowed logging of the missing cycles to better understand the intermittent generator failure issues, which varied from 1 to 5 missing cycles and did not always trigger an automatic shutdown.

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    Ideas for Design 1981_1995

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    The document describes an issue with a 400 Hz generator detecting missing power cycles and shutting down improperly. A simple interface card was built with optocouplers to monitor the 400 Hz power from the generator and send the signal to a PC. This allowed logging of the missing cycles to better understand the intermittent generator failure issues, which varied from 1 to 5 missing cycles and did not always trigger an automatic shutdown.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    17 views165 pages

    Ideas For Design 1981 - 1995

    Uploaded by

    Alessandro Vinassa
    The document describes an issue with a 400 Hz generator detecting missing power cycles and shutting down improperly. A simple interface card was built with optocouplers to monitor the 400 Hz power from the generator and send the signal to a PC. This allowed logging of the missing cycles to better understand the intermittent generator failure issues, which varied from 1 to 5 missing cycles and did not always trigger an automatic shutdown.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 165

    IDEAS FOR DESIGN

    (Ideai Bulterworth) ized low-pass filter into a high-pass


    Eldeal filter with the same corner fre-
    quency (Fig. 2a). This concept is il-
    Rload
    1k lustrated with an ideaI Butterworth
    (Normalized Bulterworth) high-pass filter transfer function
    (Eldeal):

    Notice that the Sallen-Key filter


    must be modified according to imped-
    ance levels at each node. This yields
    C1b C2b a filter with equal-value capacitors
    and unequal-value resistors, an im-
    10~nF provement over the traditional low-
    R1b 11t4k pass design of equal-value resistors
    and unequal-value capacitors.
    (a) The graphs in Fig. 2b indicate
    that the normalized high-pass filter
    compares favorably with the Sallen-
    200 m"7 - - - - - -:- - - - - - - -. - - - - - - - -----~--~-­ Key filter in high-pass applications,
    1
    1 much like the previously mentioned
    I
    ~
    1
    low-pass case. D
    1
    '1
    -50
    CI>
    ~ 100 m~I IdeaI, normalized, and Sallen·Key
    =
    ""
    <:>
    CL
    <:>
    ~ 1
    ""
    ~ ~
    ~
    1
    1
    =
    CL -100 ~ O~
    =
    <:> 1
    CI> 1
    1
    Li: -l

    -150 -100 m : - Sallen·Key ~lter-errOl'


    '1
    l---;lfll----<~----4 __ ~

    ...,
    1

    Norinalized lilter error


    -200 -200 m-j - - - - - - l - - - - - - - r - - - - - - ~ - - - - - - -;- - - - - - - ~ - - - - - - -
    1.0Hz 10Hz 100Hz 100kHz 10kHz 100kHz 1.0MHz
    Frequency
    (b)

    2. AHIGH-PASS THIRD-ORDER Butterworth filter with equal-value


    1 components can also be built Ca). The normalized filter once again compares favorably with
    the Sallen-Key in high-pass applications Cb).

    ecently, our Avionics Simu- plifier that takes three-phase, 60-Hz cles ofthe 400-Hz ac waveform. Some

    R lation Lab was given the


    task of monitoring 120-V,
    LlOO-Hz three-phase power
    to determine if there were missing
    cycles causing momentary loss of
    power and converts it to three-phase,
    400-Hz power.
    We had problems with the 400-Hz
    generator internally detecting a fail-
    ure and shutting down. Using a mem-
    of these events would occur prior to
    an automatic shutdown of the gener-
    ator, while others would not result in
    an automatic shutdown.
    A simple interface card was con-
    power to the equipment. The main ory scope, we caught the missing-cy- structed (Fig. 1) with its optocoupler
    target was our power generator, a cle problem, which was extremely in- outputs connected to the printer port
    fully solid-state switching power am- termittent and varied from 1 to 5 cy- of a standard PC (optocouplers were

    le ELECTRONIC DESIGN/AUGUST 7, 1995

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