impedance matching transformer

Discussion in 'General Electronics Chat' started by masudasim, Jul 23, 2011.

  1. masudasim

    Thread Starter New Member

    Jul 10, 2010
    15
    0
    Hi all

    I have a QSC audio amplifier (RMX 4050HD) and an acoustic transducer having input impedance of approx 180 oham at resonant frequency. QSC amplifier can provide about 2000 watt to 2 oham load (speaker) . If i directly connect transducer to amplifier, i only get 50-60 watt output. I require atleast 600-700 watt power so i need a matching transformer (probably step-up transformer) b/w transducer and amplifier.

    Can any one kindly suggest charecteristic parameters (e.g. winding ,core , insulation etc) of transformer most suitable for my application?

    Is there any software availavle for design of such transformers?Most software available on net are for RF matching transformers

    Note:My operational frequency band is about 3-5 KHz

    Best Regards
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Specifications for your amplifier are in this PDF: http://media.qscaudio.com/pdfs/Specifications/RMX_spec.pdf
    In bridged mono mode, 4 Ohms impedance, the amplifier is rated for 4000 Watts :eek:
    So, you need to have an impedance of 4 Ohms in, 180 Ohms out, centered around 4kHz.
    That's a ratio of 1:45 for impedance, and 1:6.708 for turns.

    There's a calculator here:
    http://www.bcae1.com/trnimpmt.htm

    But, it doesn't cover core materials and a number of other things.
    You will need a pretty large core for that kind of power.
     
  3. masudasim

    Thread Starter New Member

    Jul 10, 2010
    15
    0
    Dear SgtWookie

    Thanks for your helρ. Actually i have to run atleast two transducers <at 6oo watt each > from single ρoweramlifier so i am restricted to single mode.

    Best Regards
     
  4. whale

    Active Member

    Dec 21, 2008
    111
    0
    Hey guy, since you need a 4 ohms in the place of 180 ohms. You should design a step down transformer. Taking only the turns ratio into the design will wont work. At first you choose a core material which can substain your frequency with low iron loss. You can choose one from soft iron materials with low histeresis loss, ferrite. And then calculate the flux linkage at primary side , which depends on the number of turns and input current. The calculated flu*****age should not saturate the core. You should come to a turn ratio which satisfy both voltage ratio and flux density. This will be a error and try and try problem. There is software for this, magnet (fea by infolytica corporation). Its an electro magnetic analysis software and costs about 50 laks indian rupees. I think its better to do it by analytical calculation. Best of luck.
     
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