Vacuum interrupter/ operator

Introduction

The type 38-3AH3 vacuum circuit breaker is of drawout construction designed for use in medium-voltage, metal-clad switchgear. The 38-3AH3 circuit breaker conforms to the requirements of ANSI and IEEE standards, including C37.20.2, C37.04, C37.06, C37.09 and C37.010.

A type 38-3AH3 vacuum circuit breaker consists of three vacuum interrupters, a stored-energy operating mechanism, necessary electrical controls and interlock devices, disconnect devices to connect the circuit breaker to both primary and control power and an operator housing. Insulating barriers are located along the outer sides and between phases as shown in

Figure 11: Type 38-3AH3 vacuum circuit breaker with inter-phase and outer-phase barriers installed on page 17.

This section describes the operation of each major sub-assembly as an aid in the operation, installation, maintenance and repair of the type 38-3AH3 vacuum circuit breaker.

Vacuum interrupters

The operating principle of the vacuum interrupter is simple. Figure 9: Vacuum interrupter cutaway view is a cutaway view of a typical vacuum interrupter. The entire assembly is sealed after a vacuum is established. The vacuum-interrupter stationary contact is connected to the upper-disconnect stud of the circuit breaker. The vacuum-interrupter movable contact is connected to the lower- disconnect stud and driving mechanism of the circuit breaker. The metal bellows provides a secure seal around the movable contact, preventing loss of vacuum while permitting vertical motion of the movable contact.

Fixed contact-current connection

Ceramic insulator

Arc shield

Fixed contact

Moving contact

Ceramic insulator

Metal bellows

Guide

Moving contact-current connection

Figure 9: Vacuum interrupter cutaway view

When the two contacts separate, an arc is initiated that continues conduction up to the following current zero. At current zero, the arc extinguishes and any conductive metal vapor that has been created by and supported by the arc condenses on the contacts and on the surrounding arc shield. Contact materials and configuration are optimized to achieve arc motion, resist welding and to minimize switching disturbances.

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Siemens 38-3AH3 38 kV instruction manual Vacuum interrupter/ operator, Vacuum interrupters

38-3AH3 38 kV specifications

The Siemens 38-3AH3 is a high-voltage circuit breaker designed for medium voltage applications, particularly in substations and industrial environments. This device operates at a voltage level of 38 kV, showcasing Siemens' commitment to innovation and reliability in electrical engineering.

One of the main features of the Siemens 38-3AH3 is its advanced interruption technology, which employs the proven hybrid design combining both gas-insulated and air-insulated technologies. This hybrid approach not only enhances the breaker's performance and reliability but also minimizes its footprint, making it an ideal choice for space-constrained environments.

The Siemens 38-3AH3 uses vacuum interruption technology, allowing for efficient switching with minimal wear and tear. The vacuum interrupters are highly reliable and provide excellent performance under various operating conditions. This technology ensures that the circuit breaker can handle short circuits and overloads effectively, thus protecting the entire electrical system.

Additionally, the Siemens 38-3AH3 incorporates intelligent monitoring systems. These digital technologies provide real-time data on breaker status, operational performance, and maintenance needs. This predictive maintenance capability helps operators to identify potential issues before they develop into significant problems, ultimately leading to reduced downtime and maintenance costs.

Another notable characteristic of the Siemens 38-3AH3 is its high insulation strength. Thanks to its robust design and development, this circuit breaker can withstand adverse environmental conditions, making it suitable for use in diverse geographical locations and climates. Its components are designed to resist contamination and corrosion, ensuring long-term reliability.

The Siemens 38-3AH3 also offers enhanced safety features. It includes protective relays and automatic fault detection systems that isolate faults quickly, preventing damage to downstream equipment. Furthermore, the design allows for easy maintenance, with components that are accessible without the need for extensive disassembly.

In summary, the Siemens 38-3AH3 38 kV circuit breaker is a leading solution in high-voltage protection and control, characterized by its advanced interruption technology, integrated monitoring systems, high insulation strength, and user-friendly maintenance features. Its innovative design and engineering make it a trusted choice for utilities and industrial facilities aiming to enhance the reliability and safety of their electrical systems.