Inspection & Maintenance
4.4 Performing inspection
3WJ Air Circuit breakers
172 Operating Instructions, 12/2022, L1V30828903001-01
4.4.3 Check of the available documentation and of the rating/accessory label
Check the documentation and the rating/accessory label:
• Document is available and complete.
• Accessory label and labeling of operator panel, including the article number, correspond
to the installed internal accessories and available documentation.
4.4.4 Testing of mechanical function of the circuit breaker
Siemens recommends closing and opening under a load of at least 200 A.
Check the following items:
• Manual operating mechanism:
– Perform nine strokes (final stroke requires slightly more force)
– Display of charged stored-energy spring
– Ready-to-close indicator OK
Circuit breaker can be operated when OK is indicated.
• Spring charging motor (optional) with auxiliary voltage, general functioning of the motor
• CLOSE – OPEN test using shunt trip or UVR (optional)
• Operating sequence:
Charge – CLOSE – OPEN
• Operating sequence:
Charge – CLOSE – Charge – OPEN – CLOSE – OPEN
• The following conditions interfere with indication of the ready-to-close status:
– Stored-energy spring not charged
– Circuit breaker tripped by ETU without a reset of the reclosing lockout
– Undervoltage release (optional), not energized
• Effect of control gate and interlocking functions on ready-to-close indication
• Mechanical interlocking (optional):
– Mounting: Secure fitting
– Adjustment
– Function
• Permissible bending radii on the installed Bowden cables (optional)
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