ABB 1TNA900151R0100 Current Transformer KORC 4L 100/5

1TNA900151R0100

The ABB 1TNA900151R0100 KORC 4L 100/5 is a ring-type, resin-cast current transformer with four primary terminals, designed to convert a 100 Amp primary current down to a standardized 5 Amp secondary current for safe measurement and protection in electrical installations.

Let's break down the information from the model number ABB 1TNA900151R0100 KORC 4L 100/5.

This is a specific type of electrical component used for measurement and protection.

Model Number Decoding: 1TNA900151R0100

This is ABB's internal article number. While the full string is for unique identification, it tells us it's a specific, standardized part within their production system.

Key Specifications from "KORC 4L 100/5"

This part of the name contains the most critical technical details:

1. KORC: This is the series or type of the current transformer. The "KOR" series from ABB is a well-known family of resin-cast, toroidal (ring-type) current transformers. The "C" might indicate a specific variant or a class of accuracy.

2. 4L: This indicates the terminal configuration. It means the transformer has four (4) primary terminals (often labeled L1 and L2 for the incoming and outgoing line). This design allows the primary conductor to be passed through the core and connected directly to the terminals, making installation neat and secure. It's a very common style for panel building.

3. 100/5: This is the ratio of the transformer.

◦ 100: The primary rated current is 100 Amps.

◦ 5: The secondary rated current is 5 Amps.

◦ What this means: When 100 Amps flows through the primary conductor (the main power line), the transformer will output exactly 5 Amps on its secondary side. This allows you to use standard 5A ammeters and protection relays to safely measure and monitor a much higher current circuit.

What is a Current Transformer (CT)?

A Current Transformer is a type of instrument transformer designed to:

• Step down a high primary current to a low, standardized, and safe secondary current (typically 5A or 1A).

• Isolate the measuring and protection circuits (ammeters, relays, energy meters) from the high-voltage primary circuit.

How it works: The primary conductor (carrying the current to be measured) acts as a single turn. This conductor passes through the center of the toroidal (doughnut-shaped) core. The secondary winding has many turns of fine wire wound around the core. The current is transformed down by the inverse of the turn ratio.

Typical Applications for this Model

This specific CT, with its 100A primary rating and 5A output, is commonly used in:

• Electrical Panels and Switchboards: For energy metering, load monitoring, and system protection.

• Motor Control Centers (MCCs): To monitor the current drawn by large motors.

• Power Distribution Systems: To provide a signal for protective relays or power quality analyzers.

• Sub-metering: To measure power consumption of a specific section of a building or a piece of machinery.

Important Parameters to Consider (if you need to replace or select one)

While the model number gives the basics, for a full replacement or new design, you would also need to verify:

• Accuracy Class: e.g., Class 1 or Class 0.5 for measurement, or Class 5P or 10P for protection.

• Burden (VA Rating): The maximum load (in Volt-Amperes) the CT can supply to connected instruments while maintaining its accuracy (e.g., 2.5 VA, 5 VA).

• Frequency: Typically 50/60 Hz.

• Insulation Voltage: The voltage level it's designed to withstand (e.g., 0.72/3 kV).