The Terasaki XS800ns is a robust and intelligent air circuit breaker designed for the protection and control of electrical power systems in industrial, commercial, and marine applications. It's a key component in low-voltage main distribution boards.
Key Features and Highlights
Model Designation Breakdown:
XS Series: The main product family.
800: The frame size, indicating a maximum rated current of 800 Amps.
n: Standard fixed version (can also be 's' for withdrawable/slide-out version).
s: Equipped with the advanced "S-type" Electronic Trip Relay (ETR). This is a crucial differentiator, providing intelligent protection features.
Advanced Protection (S-Type Trip Unit):
This is the core of the breaker's intelligence. The S-type ETR offers highly adjustable and precise protection settings:
Long-Time Delay (L): Protects against continuous overloads. Adjustable for both current (Ir) and time delay.
Short-Time Delay (S): Protects against medium-level short-circuits (e.g., downstream feeder faults). Adjustable for current (Isd) and time delay, with an I²t IN/OUT setting for selectivity.
Instantaneous (I): Protects against high-level short-circuits and operates with no intentional time delay. Adjustable current setting (Ii).
Ground-Fault (G): Provides sensitive protection against earth leakage currents. Adjustable for current (Ig) and time delay. This is a critical feature for personnel and equipment safety.
High Breaking Capacity:
The XS800ns is designed to interrupt very high fault currents safely, typically in the range of 50kA to 100kA (depending on the specific voltage rating), ensuring system safety under severe fault conditions.
Communication Capability (Optional):
The S-type trip unit often comes with an optional communication module (e.g., Terasaki's TML-CM or compatibility with standard protocols like Modbus). This allows for:
Remote monitoring of current, voltage, power, and energy.
Remote control (open/close).
Data logging and event recording.
Integration into Building Management Systems (BMS) or SCADA systems.
Durability and Reliability:
High Mechanical Life: Rated for thousands of operations.
Robust Construction: Built to withstand harsh environments, making them a preferred choice for the marine and offshore industries.
Clear Status Indication: Visible contact position indicators (ON, OFF, TRIPPED) and spring-charged state.
Technical Specifications (Typical)
Feature Specification
Frame Size 800A
Rated Current (Iu) Adjustable via the S-type ETR, typically from 400A to 800A.
Rated Insulation Voltage (Ui) 1000V AC
Rated Operational Voltage (Ue) 690V AC
Breaking Capacity (Icu) Up to 100kA at 415V AC (Confirm with specific datasheet).
Trip Unit Electronic (S-Type)
Standard Complies with IEC 60947-2
Common Applications
The XS800ns is used as a main incoming breaker or a critical feeder breaker in various settings:
Industrial Plants: Main power distribution, protecting large motors, transformers, and busbars.
Commercial Buildings: As the primary breaker in the main LV switchboard for large offices, hospitals, and data centers.
Marine & Offshore: A Terasaki specialty, used on ships, oil rigs, and port facilities due to their corrosion resistance and reliability.
Infrastructure: Power distribution in airports, railway stations, and water treatment plants.
Advantages of the Terasaki XS Series
Selectivity: The adjustable short-time and ground-fault delays allow for excellent coordination with downstream breakers, minimizing the impact of a fault by isolating only the affected circuit.
Accuracy: Electronic trip units are far more precise than older thermal-magnetic mechanisms, leading to better equipment protection and fewer nuisance trips.
Flexibility: The adjustable settings allow one breaker frame to be used for a range of specific load requirements.
Diagnostics: The communication and event logging features help maintenance teams quickly diagnose the cause of a trip, reducing downtime.
Important Considerations
Configuration: The protective functions (L, S, I, G) must be correctly set and coordinated by a qualified electrical engineer based on a discrimination study.
Maintenance: Like all critical protection devices, they require periodic inspection and testing as per the manufacturer's guidelines and local regulations.
Withdrawable Version: For critical applications where downtime must be minimized, the XS800s (withdrawable version) is preferred as it allows for easy isolation, testing, and maintenance without de-energizing the entire busbar.
The Terasaki XS800ns is a high-performance, intelligent air circuit breaker renowned for its reliable protection, advanced features, and ruggedness. Its S-type electronic trip unit makes it a versatile and precise choice for managing and safeguarding electrical power in demanding environments worldwide.