ABB 1TNA900151R0300 Current Transformer KORC 4L 300/5

ABB 1TNA900151R0300 Current Transformer KORC 4L 300/5

Let's break down the product code ABB 1TNA900151R0300 Current Transformer KORC 4L 300/5.

This alphanumeric string is a standard industrial part number that describes the transformer's key specifications. Here is a detailed explanation of what each part means:

Full Code Breakdown:

1. ABB

◦ Manufacturer: This is a product from ABB, a leading global technology company in electrification and automation.

2. 1TNA900151R0300

◦ Article Number / Catalog Number: This is the unique identifier for this specific product in ABB's catalog. You would use this exact number when ordering a replacement.

3. KORC

◦ Product Series/Type: This indicates the specific family or model of the current transformer. The KORC series is a well-known line of ABB ring-type current transformers (often called "doughnut" CTs) designed to be mounted around a conductor.

4. 4L

◦ Accuracy Class: This is a critical specification.

◦ 4 means the transformer has a guaranteed accuracy within ±4% at its rated current.

◦ L indicates it is designed for Measurement/Energy Metering purposes. Accuracy classes for metering (like 0.5, 1, 3) are different; a class 4L is typically used for Protection Relays.

◦ Interpretation: This CT is not intended for precise revenue metering but for supplying a reliable current signal to protective devices (like overcurrent relays) that will trip a circuit breaker during a fault.

5. 300/5

◦ Rated Current Ratio: This is the most important functional specification.

◦ 300 is the rated primary current. This CT is designed to be used on a circuit where the normal full-load current is around 300 Amps.

◦ 5 is the rated secondary current. When 300A flows in the primary conductor, the CT will output a proportional 5A current on its secondary terminals.

◦ How it works: This 300:5 ratio (or 60:1) allows you to use standard 5A ammeters and protection relays on very high current circuits safely.

Summary of Key Specifications:

Feature

Specification

Meaning

Manufacturer

ABB

A major, reputable brand.

Type

Ring Type (KORC Series)

Installs by passing a cable through the center hole.

Primary Current

300 A

The circuit current it's designed for.

Secondary Current

5 A

The safe, standardized output current.

Ratio

300/5 (60:1)

Scales down the primary current by a factor of 60.

Accuracy Class

4L

Suitable for Protection Relays (not precision metering).

Typical Application:

This current transformer is used in electrical switchboards and distribution panels. Its primary job is to:

1. Isolate the high-current primary circuit from the sensitive control and protection circuits.

2. Step Down the current to a safe, measurable level (5A).

3. Supply a signal to a protective relay (e.g., an overcurrent or earth fault relay). If the current exceeds a preset threshold, the relay will signal a circuit breaker to open, protecting the equipment and personnel.