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Another circuit to analyse (MALAXOR speed variator)

Discussion in 'General Electronics Discussion' started by Elecbegginner, Jul 6, 2013.

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  1. Elecbegginner

    Elecbegginner

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    Mar 24, 2013
    Am really interested in this shematic that belongs to a MALAXOR with speed variation , and i want to know if possible step by step how it works and what role plays the transistor and the triac in it .
    So the card actually have a 220 v AC input with two terminals M1 and M2 that goes to a mono-phase motor. this motor's speed is variated by the system .
    So at first :
    Whats the role of those SR caps , why is it necessary to us them. .?
    What is the role of the triac and the transistor in the system and also the relay ?
    How speed is beign variated ?

    Here is some pictures and shematic also .

    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
     

    Attached Files:

    Last edited: Jul 8, 2013
  2. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    Nov 28, 2011
    There are two definite errors in your schematic: the cathode of D1 must connect to a voltage rail so the relay coil can be energised, and the right hand terminal of the triac must connect to something apart from the resistor-capacitor suppression network that's connected across it.

    You may find it helpful to take photos of both sides, load them into an image editor that supports multiple layers, mirror the bottom photo, and align them so the tracks on the bottom layer coincide with the components on the top layer. (You may need to resize the track layer so its scale matches exactly.)

    You can then create a layer with component references and values, and you can number the tracks with "net" or "node" numbers, which you can match up on your schematic, to act as a check between the PCB and the schematic.

    Triac- and SCR-based speed controllers operate like light dimmers. They enable the mains supply to the motor for a certain proportion of each half-cycle of the mains voltage. Google light dimmer for an explanation of how they work.
     
  3. Elecbegginner

    Elecbegginner

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    Mar 24, 2013
    I completed the schematic , i will try to do the photo editing , but for now the problem with the card is that before i change the transisor ; i was able to turn the motor with 2 speeds the relay was energized as soon as i plug in the input voltage , after i checked the transistor i found out that it was bad , then i changed it with one with the same number , now its worse i don't have any rotation in every switch position i choose , am really lost .
     
    Last edited: Jul 8, 2013
  4. Elecbegginner

    Elecbegginner

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    Mar 24, 2013
    Is the triac that controls the motors speed ??
     
  5. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    The triac switches ON at a specific point in each half-cycle of the AC mains waveform. This is called phase angle control. Read up on incandescent lamp dimmers to understand how it works. The other components are (mostly) to control the triac so that it switches on at the right time.
     
  6. Elecbegginner

    Elecbegginner

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    Mar 24, 2013
    BTW do you get a clear idea after i corrected the shematic , what's your definition of this circuit ?

    And do you have an idea on how to check a triac ??
     
  7. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    ElectBeginner, don't update your posts like that. Make a new post with the new information.

    And I think the "correction" is still wrong.

    Did you do as Kris suggested?
     
  8. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    I agree, that "correction" still isn't right. There's no DC path to the top of the relay coil.

    You will save time in the long run if you do what I suggested. Take photos of both sides, and use an image editor to mirror the bottom, and rescale and align them. Read my earlier post.

    If you don't have an image editor, google paint.net. It's free and quite good. While you're there, read up on lamp dimmers to get an understanding of how it works. Or do I need to suggest it a fourth time?

    You can check a triac out-of-circuit. You need a power supply or battery (12V is good), a load (a light bulb is good) and a resistor (1k or so). Connect power source positive to the load, and the other side of the load to the MT2 pin. Connect the MT1 pin to power source negative. Connect the resistor to power source positive and touch the other end on the gate. The light should illuminate and stay lit until you disconnect it.
     
  9. Elecbegginner

    Elecbegginner

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    Mar 24, 2013
    Am actually trying to finish it i will let you know when i get it done , and also the triac test .
    I have a lot of exams this week , i don't have time be always online .

    Thanks for the help anyways , i really appreciate it .
     
  10. Elecbegginner

    Elecbegginner

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    Mar 24, 2013
    I finally fixed this card , its working fine right now , the problem was due to some faulty resistors , a transistor , and a triac .
     
  11. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    Glad to hear that but mark you're schematic as "Error On Print!" so in the future you remember that. ;)

    Chris
     
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