ABB Air Circuit Breaker E4.2 4000 A

Check that the vertical or horizontal interlocking devices are installed and operate correctly

Ensure interlocks are not tested in the Test or Disconnected positions

Perform maintenance periodically as indicated

Frequency: Three years or 50% of the mechanical life or 50% of the electrical life of the largest circuit-breaker involved in the interlock

Frequency: After a trip due to a short-circuit

Maintenance operations: Replacement is advisable

Set the circuit-breaker to the open position and ensure the springs of the operating mechanism are discharged

Work with the circuit-breaker removed from the fixed part

Disconnect the power circuit and auxiliary circuits and earth the terminals visibly on both the supply side and load side

Clean and Lubricate Jaw-Type Isolating Contacts

Disassemble the safety shutters (only IEC) before cleaning and lubricating the jaw-type isolating contacts

Clean the jaw-type isolating contacts using a laminate thinner such as Chemma 18 or equivalent if there is a heavy coating of dirt

Lubricate the jaw-type isolating contacts with Mobilgrease 28 at the indicated points

Power the gearmotor to charge the springs at the relevant rated voltage

Perform some closing and opening operations

Power the undervoltage coil and perform the closing operation on the circuit-breaker

Turn off the voltage supply to the trip unit

Power the undervoltage coil again and perform the closing operation on the circuit-breaker

Select the maintenance frequency based on environment

Set the circuit-breaker to the open position and discharge the springs of the operating mechanism

Is the circuit-breaker withdrawable?

Disconnect power supply to power circuit and auxiliary circuits and visibly ground the terminals on both supply and load sides

Inspections and General Cleaning

Ensure the circuit-breaker is clean

Remove dust and oily substances with a clean, dry cloth and mild detergent if necessary

Check that the interlocking devices are installed and operate correctly

Ensure interlocks are not tested in the Test or Disconnected positions

Perform maintenance periodically as indicated in the table below

Refer to kit sheet for maintenance operations

Frequency of lubrication as shown in the figure

Use Mobilgrease 28, also available in the ABB greasing kit