Racking crank engagement procedure

Installation checks and functional tests

Heavy weight.

Can result in death, serious injury or property damage.

Do not transport a circuit breaker using a lift truck with the lift truck in the raised position.

Figure 2: Type 38-3AH3 vacuum circuit breaker racking

5.Move the circuit-breaker release latch (on the floor of the cell near the right side of the circuit breaker) to the left and pull the circuit breaker out from the DISCONNECT position. The circuit breaker can now be removed from the cubicle and rolled out onto the two extension rails.

6.Remove the circuit breaker from the two extension rails using the approved Siemens circuit-breaker lifting device or Siemens lifting sling and a suitable crane.

7.Lift the two extension rails and withdraw them from the switchgear.

8.Close the circuit-breaker compartment door and secure all latches.

Type 38-3AH3 vacuum circuit breakers weigh between 800 and 1,000 lbs (364- 455 kg) depending upon ratings. The circuit breaker can be moved using a properly rated crane and lift sling. A lift sling can be attached to the circuit breaker, and then used to hoist the circuit breaker vertically clear of the extension rails. When clear, remove the rails and lower the circuit breaker to the floor.

A crank for racking the circuit breaker is provided as a standard accessory. Racking a circuit breaker can be accomplished with the drawout-compartment-front door open or through a small opening (or window) in the front door, with the door closed. Racking a rollout-fuse truck is accomplished with the compartment-front door open.

The racking crank consists of an offset handle with a custom socket assembly welded to the end. The socket end of the crank is designed to engage the shoulder of the racking-mechanism shaft and remain engaged during racking with spring plungers. The plungers operate in a manner similar to the retainers of an ordinary mechanic’s socket wrench.

The portion of the racking-mechanism shaft visible is cylindrical, and the shoulder of the racking-mechanism shaft is hidden by a shroud until the engagement procedure starts. The square socket-end of the crank will only engage the shoulder of the shaft if it is aligned properly.

Figure 3: Use of extension rails for voltage transformer (VT) fuse- rollout truck or circuit breaker not at floor level (VT fuse-rollout truck in upper cell shown. Procedure for circuit breaker in lower cell but not at floor level is similar.)

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.