ABB Power Services

Our aim is to increase systems reliability and extend the life of their equipment with concomitant gains for our customers’ competitiveness. We support our customers with high-quality services in preventive and corrective maintenance to improve risk mitigation and improved safety. ABB's service portfolio allows utilities and industrials to maximizing the return on all assets by ensuring a high reliability, reducing life cycle costs and ensuring optimized performance while lowering environmental impact.

Wednesday, November 30, 2011

Locating leaks in your Westinghouse Pneumatic Operating Mechanisms

Have you noticed an audible leak or the compressor has an excessive run time as compared to previous inspections? If so, then you may have a leak in the air piping between the air reservoir and the breaker control valve.

Hello, Herb here. I’d like to explain about pneumatic mechanisms on your Westinghouse high voltage circuit breakers and the need for an upgrade replacement kit. The earlier vintages of pneumatic mechanisms AA7, AA10, & AA14 were fitted with Dresser type fittings on the air piping between the air reservoir and breaker control valve. These fittings were made up of an elastomer seal, stainless steel cup and cast iron nut.  Over time the elastomer seal begins to deteriorate and/or shrink, requiring maintenance personnel to tighten the nut to temporarily fix the leak.  Eventually the elastomer needs to be replaced.  To eliminate these seals, Westinghouse developed a replacement kit with a flexible hose and threaded connections.  The globe valve was also replaced with a ball valve since the globe valve and parts for the globe valve are no longer produced.  The picture on the right is the replacement kit for the AA10.  Kits for the AA7 & AA14 are also available.

Original design
Upgrade replacement kit
Contact High Voltage Service if you need assistance with your Westinghouse mechanism or circuit breaker at 724-696-1300.


nr said...

Thank you for sharing this information.
It will really helpful to solve my confusion

Process $ Chemical Engineering

Zhu Y said...

We pneumatic products manufacture several products, including solenoid valves,air control valves, piston air cylinder, Pneumatic Air Filter and some pneumatic accessories. Most of goods are exported to USA, Europe and Asia. And they are widely used on electronic, pharmaceutical, food processing, packaging, medical and automotive industries. Visit:

Post a Comment