Assistance needed in a high voltage circuit

Discussion in 'Power Electronics' started by AlekhyaMuvva, Jun 3, 2017.

  1. AlekhyaMuvva

    Thread Starter New Member

    Jun 3, 2017
    2
    0
    Hello All,
    I am new to electronics, I am mainly in production.
    I am facing problem in a 7kw UV Plate Exposure Machine where a contactor is burning out.

    I am Attaching the circuit diagram. "MC3" is what that is burning.
    Can anyone suggest what could be the problem?

    The purpose of this machine is when I power ON the UV Lamp it is used to expose the plate in Pre Press Process in printing.

    There is an electronic program that
    1. Switches On Vaccum for specified time
    2. Switches ON UV Lamp.
    3. Switches OFF UV Lamp.

    There are manual Switches also using which we can operate.
    When ever I am switching ON the Lamp the contactor is burning OUT.

    Thanks & Regards,
    Alekhya. Muvva
     
  2. dendad

    Distinguished Member

    Feb 20, 2016
    2,826
    764
    What is "Burning Out"?
    Is it the contacts or the coil failing?
    If the contactor cannot mechanically close fully, its inductance will be lower that it should be so the coil current will be higher and could cause it to fail.
     
  3. AlekhyaMuvva

    Thread Starter New Member

    Jun 3, 2017
    2
    0
    Coil is burning
     
  4. dendad

    Distinguished Member

    Feb 20, 2016
    2,826
    764
    Has this just started happening or is it an ongoing problem?
    What voltage coil are you putting in?
    If it is correct, as I mentioned above, check that the armature of the contactor fully closes as I've seen them burn out if they don't. Have a look at the general health of the contactor to see if it is not mechanically damaged. Too big an air gap reduces the inductance so that excess current flows.

    Remember to make sure the mains is isolated before you do anything with it too!
     
  5. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
    8,133
    1,409
    Is it MC1, terminals A1,2, if so can you measure the coil voltage as the other contactors are all 230V single phase. ?
     
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