Introduction
The ABB TD-5 Time Delay Relay is a specialized device engineered for critical timing applications within nuclear power generating stations, specifically for Class 1E applications. These applications are essential for ensuring the safety and emergency shutdown procedures of the reactor, containment isolation, and heat removal systems, thereby preventing the release of radioactive material.
This relay offers high accuracy, repeatability, and fast reset capabilities, making it suitable for time-delayed distance relaying and breaker failure timing. It operates on DC power and covers a timing range from 0.05 to 30 seconds across four distinct ranges.
Key Features and Components
The TD-5 relay comprises several key components:
- A reference voltage circuit for stable operation.
- A rheostat (T) for time delay adjustment, featuring a non-linear scale.
- A potentiometer (P) for biasing voltage.
- A printed circuit board housing static timing components, including silicon-controlled rectifiers (SCRs), diodes, capacitors, and resistors.
- Miniature power relays (TR and TX) for output switching.
- An indicating contactor switch (ICS) for visual status indication.
Applications and Operation
The TD-5 relay is designed for applications requiring precise timing. Its operation is initiated by an input voltage, which charges a capacitor. When the capacitor voltage reaches a set threshold, it triggers an SCR, which in turn energizes the TR relay. The TX relay, when used, provides a means to maintain timing module voltage during potential contact bounce of the initiating relay.
The document details various settings and adjustments, including time delay, voltage rating selection, and specific configurations for the TX relay. It also provides guidance on installation, routine maintenance, and troubleshooting procedures to ensure optimal performance and longevity of the relay.
Further Information
For detailed information regarding installation, operation, or maintenance, it is recommended to contact the local ABB representative.
