Maintenance and Troubleshooting

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Maintenance and Troubleshooting

  • Check the P/N, specification, control voltage before mounting;
  • The mounting surface should be clean and smooth, mounting feet bear even stress and the fastener should be solid and reliable;
  • Ensure no foreign body entering into contactor or it will be stuck;
  • Electrical connection should not have stress on contactor;
  • Clean the insulating frame, vacuum interrupter and electrical system regularly to ensure insulation;
  • Check if the fastener is loosening and if the structural component is normal;
  • Check the erosion condition of auxiliary contact, repair or change if necessary;
  • Check the flexibility of the movable parts, add lubricant if necessary;
  • Check if the contact stroke and overtravel can meet the requirement;
  • Generally using power frequency withstand voltage methods to check the vacuum degree of the vacuum interrupter, its withstand voltage should no less than the half rated value;
  • Common failure and solution please refer to chart.                           

Chart 1-Troubleshooting




1.No reaction after power on or with electromagnetic acoustic but not closing (power off at once)

  • no power or lower voltage
  • with break line in control loop
  • Problem with the auxiliary switch. NC contacts is open
  • broken rectifier
  • stuck

  • check the power and connection
  • check the connector bar, power terminal, auxiliary switch terminal
  • adjust contact stroke of auxiliary switch or change auxiliary switch
  • change power panel
  • check if any foreign bodies enter into the contactor, check the insulator, check if interrupter is stuck; can operate respectively

2.Can not close and become double hit

  • problems with power panel
  • problems with coil
  • with foreign body in the in the iron core
  • incorrect switching position of auxiliary switch
  • incorrect mechanical latching

  • change power panel
  • change coil
  • clear up foreign body
  • Adjust the position of contact stroke of auxiliary switch
  • adjustion

3.Slow operation

  • 1.lower power voltage
  • 2.stuck
  • 3.inappropriate opening spring force 

  • elimination
  • check if insulator, interrupter are stuck, add a little lubricant and operate respectively
  • make adjustion


  • mounting surface is unlevel and has deformation
  • large tensile force of inlet and outlet conducting bar cause deformation of product
  • uneven of pick-up in electromagnetic system

  • use washer to level up
  • correct the dimension of applied conducting bar, can not force it by bolt 
  • clear up the foreign bodies on the pick-up surface or level it

5.Coil is hot or burn out

  • Higher power voltage
  • Problem with the auxiliary switch. NC contact is close.
  • Insulation breakdown of coil
  • Stuck and no operation

  • Check the voltage
  • Adjust contact stroke of auxiliary switch or change auxiliary switch
  • Change
  • Check all the movable parts