3 Phase failure detection

Discussion in 'The Projects Forum' started by karunanithi_pricol, Apr 5, 2006.

  1. karunanithi_pricol

    Thread Starter Member

    Mar 13, 2006
    19
    0
    Hi Everyone
    I want to design a alarm circuit to detect single phasing, (ie) This circuit should sense all the three phases and should indicate a alarm incase of any one phase failure.
    The alarm circuit should be innovative so that after the occurence of single phasing it should dial a particular telephone number.

    Can any one suggest me a sloution for my requirement with schematic? Early thanks to all.

    Regards
    Karunanithi.R
     
  2. Papabravo

    Expert

    Feb 24, 2006
    9,912
    1,724
    Are you talking about three phase AC power? At what nominal voltage?

    After the telephone number is dialed, then what? Does the person who answers hear dead air? Is there a voice message? Is there an SMS text message?

    How much would you be willing to pay for such a design?
     
  3. karunanithi_pricol

    Thread Starter Member

    Mar 13, 2006
    19
    0
    Hi
    Thanks for the response.

    1.Yes it is a 3 phase AC power 440V RMS Line-Line voltage
    2.It will be better if we provide a voice message.
    3.How much you are expecting?
     
  4. Papabravo

    Expert

    Feb 24, 2006
    9,912
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    Well the detection of a dropped phase is the easy part. The hard part is the dialer, the voice recording and playback, and the memory to store the recorded message.

    I estimate that this project will take about 400 man hours. The deliverables would be:

    1. Schematic
    2. Layout with gerber files
    3. Firmware source code
    4. Firmware development tools
    5. A couple of prototypes

    For that effort you we would need about USD 60,000.00 in maybe three installments.

    How many units per year do you think you can sell?
     
  5. paultwang

    Well-Known Member

    Mar 8, 2006
    80
    0
    Can you reprogram one of those commercial one-touch emergency dialers?
     
  6. Papabravo

    Expert

    Feb 24, 2006
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    I don't know. Which one-touch emergency dialers are you talking about?
     
  7. paultwang

    Well-Known Member

    Mar 8, 2006
    80
    0
    example product
     
  8. Gadget

    Distinguished Member

    Jan 10, 2006
    613
    0
    There are lots of voice "Autodialers" on the market, intended for the security industry. I use them regularly for many apps, including Frost alerts in orchards, Irrigation/pump failure alerts, and YES, power failure (Some also accept incoming calls and will activate relays via a touch tone code....useful for remote switching).
    Easiest way to detect is to have each phase monitored with a simple relay. Wiring the N/C contacts in parallel (which should be Open when a phase is present) will close the circuit if a single phase fails, activating the attached and programmed dialer. A Backup battery and charging system is also needed, otherwise there might be no power to work the dialer.... ;)
     
  9. karunanithi_pricol

    Thread Starter Member

    Mar 13, 2006
    19
    0
    Hi Gadget
    Thanks verymuch.Exactly what i am looking for! Can you suggest me a simple low cost autodialers for this application.

    Regards
    Karunanithi.R
     
  10. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    I think Radio Shack makes something you could use.
     
  11. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
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    I am familiar with DACs that communicate digitally. Are there any commonly available that do recorded voice?
     
  12. Papabravo

    Expert

    Feb 24, 2006
    9,912
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    I think there is only one kind of DAC and it communicates digitally. The analog output may be either a current or a voltage. Recorded voice, and music for that matter, uses a DAC to reproduce an analog waveform. They do this by updating the digital word which controls the analog output at typical frequencies of 20-40 kHz. This would be every 25 to 50 microseconds. At 40 kHz. it takes 1.6 Megabytes to store 40 seconds worth of digital voice. Most embedded processors have no ability to store that much raw data internally.
     
  13. windoze killa

    AAC Fanatic!

    Feb 23, 2006
    605
    24
    Not sure about DACs but there are some great chips from a company called Aplus. I think their site is www.aplus.com.tw
     
  14. dtiger2k

    Member

    Mar 29, 2006
    10
    0
    Edited to remove. Just thought I'd offer. I didn't really need them for anything.
     
  15. Gadget

    Distinguished Member

    Jan 10, 2006
    613
    0
    The units I use are EDAC222 dialers with 2 inputs, 2 outputs, several messages and parameters, and 2x5 sets of dial up numbers, made here in New Zealand. They are around $400NZ retail, but there are lots of cheaper units out there. Contact an Alarm specialist, they'll sell ya something.
    Edac222
     
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