ABB SafeGear - Appendix G: Vacuum Interrupter Maintenance; Vacuum Interrupter Checks and Testing

Appendix G
Maintenance Procedure for Vacuum Interrupter
Always keep in mind the recommended safety procedures when working in medium voltage equipment.
For the safety of personnel extracting the controller of the MCC, all components should be electrically disconnected by means of a visible break, securely grounded,
locked out and tagged in accordance with personnel precautions spelled out in ANSI/ASSE Z244.1 “Control of Hazardous Energy – Lockout/Tagout and Alternative
Methods”.
Procedure
• Check the upper and lower anges and interrupter shaft to see if they are
contaminated or corroded.
If contaminated use a clean cloth and rubbing alcohol.
If corroded replace with a new interrupter.
NOTE: Avoid touching the ceramic surface. Skin oils may
harm the silicon varnish.
• Check the main contact wear in the vacuum interrupter.
If the wear gauge can be inserted, then there is sufcient contact material
available for continued use.
If the gauge cannot be inserted, replace the interrupter.
NOTE: This check is made with the controller closed.
• Check vacuum in the vacuum interrupter.
Apply 10kVAC between the upper and lower terminals for one minute.
If there is no voltage breakdown, the vacuum interrupter is acceptable for continued use.
If there is voltage breakdown, replace with a new vacuum interrupter before continued use.
NOTE: If there is a vacuum failure, it can be conrmed by pushing down on the insulating ange below the vacuum interrupter.
If the interrupter shaft can easily be moved, then the interrupter has lost vacuum.
UPPER
FLANGE
LOWER
FLANGE
SHAFT
WEAR
GUAUGE
2.7 mm
MINIMUM
INSULATION
FLANGE
23 SafeGear
®
Motor Control Center Controller Installation, Operation and Maintenance Manual