Medium-Voltage Vacuum Replacement Generator Circuit Breakers

Tested to IEC/IEEE 62271-37-013 and suitable for generators up to 400 MW

Replacement generator circuit breakers (GCBs) provide a cost-effective way to upgrade from gas to current vacuum technology while increasing equipment reliability and minimizing downtime. Siemens offers medium-voltage vacuum replacement generator circuit breakers for leading OEM models for voltages up to 24 kV with interrupting capabilities up to 100 kA for both indoor and outdoor applications.

Why upgrade to replacement vacuum generator circuit breakers?

Reduce lifecycle maintenance

  • Expected life of 30,000 mechanical operations utilizing Siemens 3AH operator

  • Up to 50 full-fault interruptions

Reduced operating and maintenance expenditures

  • Significantly lower lifecycle cost than gas circuit breakers

  • No major maintenance required for 10 years or 10,000 mechanical operations

Improved employee and environmental safety by eliminating SF6 gas

  • Eco-friendly vacuum interruption with low carbon footprint

  • No gas handling equipment required

Preserved investment in existing cubicles

  • No modification to cubicles needed

Reduced downtime and minimal changeover time during upgrade

Siemens Innovation: Bringing vacuum to the generator switching application

  • Siemens 3AH38 is the first vacuum circuit breaker with 63kA and 72kA to be type tested per the criteria of IEC/IEEE 62271-37-013.

  • Siemens 3AH37 is the first vacuum circuit breaker worldwide that can carry a normal current up to 6,300 A sustained at up to 24 kV controlling short circuit currents up to 72 kA without forced cooling.  Moreover it can handle up to 8,000 A with forced cooling.

  • Vacuum offerings for ratings up to 24 kV, 100 kA and 12,500 A.

Custom engineered and installed medium-voltage vacuum generator circuit breaker.

Custom engineering for easy installation

Siemens replacement generator circuit breakers are custom engineered to fit each application.

  • Little-to-no cubicle modification

  • Custom wiring and controls engineered in North Carolina, USA

  • Maintain existing connectors and other peripherals

3AH operator

Quality starts at the core

Siemens core 3AH operator is featured in our entire medium-voltage circuit breaker product line, including our replacements, providing an extremely reliable standard design allowing for streamlined parts and maintenance translating into cost savings.


3AH benefits:

  • Type tested according to IEC/IEEE 62271-37-013

  • Low maintenance - 10 years/10,000 operations

  • No re-lubrication or re-adjustment required over service life of more than 20 years (3AH37/38)

  • Full spring mechanism - no hydraulic components

  • Standardized training across Siemens medium-voltage products

3AH operator features:

  • Spring charge motor mechanism with lifetime lubricated gear box

  • Operating linkages with machined parts, not stamped metal

  • Change-out of components are easily accessible

Generator circuit breaker on-site, ready for retrofit and installation..

Siemens technology

Our vacuum generator circuit breakers are manufactured in Germany and delivered to your site for modification and installation. The Berlin factory has been producing circuit breakers since 1920.

The vacuum generator circuit breaker retrofit is performed on-site by Siemens field engineers. Our National Field Service organization is headquartered in Wendell, North Carolina, located just east of Raleigh. Siemens has been assembling low- and medium-voltage replacement circuit breakers at this location since 1980.

Major cost savings with vacuum replacement generator circuit breakers

With minimal operational and maintenance expenses adding up to significantly lower lifecycle costs, upgrading from gas to vacuum technology provides a quick payback on your investment.

  • Siemens purchase price can rival the cost of some major maintenance intervals alone

  • Eliminate overhauls and major rebuilds throughout the lifecycle of your circuit breaker

  • Investment in your switchgear is preserved

National Field Service

Siemens Field Service organization can offer local support for your electrical equipment needs. For service or parts, call our 24/7 Customer Care Center.

Phone: 1-800-333-7421

To request a service or parts quote online, visit:

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