Fracture Resistant Modules
The pictures to the left shows a crack in a module housing caused by over tightening a module mounting bolt. This crack can progress into a fracture as shown in the next picture. A module with a fractured flange is insecurely mounted and could cause a failure. The picture to the above right shows how fracture resistance is improved by contouring the module housing around the bolt hole.
Mitsubishi™ Vacuum Interrupter
The Vacuum Electric Switch Co. uses Mitsubishi™ vacuum interrupters to build its vacuum interrupter modules. Mitsubishi’s™ vacuum interrupter failure rate is less than three vacuum interrupters per 100,000 vacuum interrupters per 100,000 hours of operation.