ABB 1TNA900151R0150 Current Transformer KORC 4L 150/5

This is an ABB brand, KORC series, indoor-use, busbar (window-type) current transformer. It is designed to measure electrical current in a high-power circuit and reduce it to a safe, measurable value for meters and protective relays.

Part Code Breakdown: 1TNA900151R0150

• 1TNA: This is the prefix for ABB's product group for Low Voltage Instrument Transformers.

• 900151: This is the unique article number or specific product code for this particular model within the KORC series.

• R0150: This suffix often refers to a specific variant or production run. In this context, it's closely tied to the ratio.

Key Technical Specifications

• KORC: This is the product series name. The KORC series from ABB is a well-known range of resin-insulated, ring-core (window-type) current transformers for indoor use.

• 4L: This indicates the accuracy class.

◦ 4 means the transformer has a composite error of ≤ 4% at the accuracy limit current. This is a standard class for protection cores (typically used for tripping circuit breakers during faults, not for precise revenue metering).

◦ L indicates that the CT has a low leakage flux design, which helps maintain accuracy even when the primary conductor is not centered in the window.

• 150/5: This is the ratio of the current transformer.

◦ 150: The primary current rating. When 150 Amps flow through the primary conductor (the busbar or cable passing through the window), the CT will produce its rated secondary current.

◦ 5: The secondary current rating. At 150A primary current, the CT will output 5 Amps. This is the standard value for connecting to ammeters, protection relays, and energy meters.

Physical and Installation Details

• Type: Window-type (or Ring-type). It does not have a built-in primary winding. Instead, the main power cable or busbar of the circuit acts as the single primary turn, passing through the central window.

• Insulation: Resin Cast (Epoxy). This provides excellent electrical insulation, mechanical strength, and protection against environmental factors like humidity and dust, making it suitable for indoor switchgear and panel boards.

• Mounting: Typically mounted on a DIN rail or a flat surface using a bracket.

• Terminals: Has screw terminals for connecting the secondary wires (typically small gauge wires for the 5A signal).

Typical Applications

This specific CT (150/5, Class 4L) is commonly used for:

• Electrical Protection: Feeding current signals to overcurrent and earth fault protection relays in Low Voltage switchboards.

• Load Monitoring: Connecting to ammeters or energy management systems to monitor the current in a feeder circuit.

• General Purpose Metering: For non-billing (check metering) applications where high precision is not required.

Summary

In simple terms, the ABB 1TNA900151R0150 KORC 4L 150/5 is a robust, indoor current transformer that you would install around a main power cable. It safely reduces the high current (up to 150A) in that cable down to a standardized low current (5A) that can be easily and safely used by protective relays and meters to monitor and safeguard an electrical system.