ABB 1TNA900111R0300 Current Transformer CT KORC 4L 300/1A

ABB Current Transformer KORC4L400/5

ABB 1TNA900111R0300 is a thermal overload relay used with ABB Tmax XT series molded case circuit breakers, specifically model T1U320. Its main function is to provide overload and phase loss protection for motors, making it a key protection component in the motor control center (MCC).

Detailed Product Introduction

1. Product Name and Series

• Product Name: Thermal Overload Relay

• Series: ABB Tmax XT Series

• Specific Relay Model: T1U320

• Complete Product Code: 1TNA900111R0300 is ABB's internal order number, used to uniquely identify this specific configuration of the T1U320 relay.

2. Main Functions

• Overload Protection: By simulating the heating characteristics of a motor, when the motor current exceeds the rated value for an extended period (e.g., due to mechanical jamming, excessive load, etc.), the bimetallic strip inside the relay will bend due to heat. After an inverse time delay (the larger the current, the shorter the action time), the trigger mechanism disconnects the control circuit, thereby cutting off the contactor and protecting the motor from burnout.

• Phase Loss Protection: When one phase of the three-phase power supply experiences an open circuit, the motor winding current will rise sharply. This relay can detect this imbalance and act quickly to protect the motor.

• Manual/Automatic Reset: Typically equipped with a selector switch, allowing selection between manual and automatic reset after a fault trip.

• Test Function: Equipped with a test button to simulate overload action, facilitating equipment debugging and maintenance.

• Trip Indication: A clear indicator shows whether the relay tripped due to a fault, facilitating troubleshooting.

3. Key Technical Parameters

• Frame Current: Belongs to the T1U frame.

• Rated operating current Ie: 32 A (This is the meaning of "320" in the T1U320 model).

• Current adjustment range: The relay's operating current value can typically be precisely set within a certain range (e.g., 18-32A) to match the actual rated current of the protected motor. This is achieved via a knob.

• Installation method: Designed for direct installation on specific fuse switches, disconnectors, or contactors in the ABB Tmax XT series, forming a complete motor starting and protection solution. For example, it is often used with switches such as the XT1B160.

• Standards compliance: Complies with international electrotechnical standards such as IEC/EN 60947-4-1 and IEC/EN 60947-5-1. 4. Application Areas

This relay is widely used in applications requiring reliable protection for small to medium power three-phase asynchronous motors, such as:

• Industrial production lines (conveyors, pumps, fans, compressors, etc.)

• Building automation (air conditioning systems, water pumps, elevators, etc.)

• Water treatment plants

• HVAC systems

5. Appearance and Installation

• Typically housed in a black plastic casing with a transparent window on the side showing the current setting and tripping status.

• Features a red manual reset/test button and status indicator on the top.

• Terminal blocks on the bottom for connecting the main circuit (to the contactor output and motor) and auxiliary contacts (normally open/normally closed contacts for connecting control circuits and indicator lights).

The ABB 1TNA900111R0300 (T1U320) is a reliable and widely used 32A thermal overload relay. It is an important member of the ABB Tmax XT low-voltage component family. With its stable protection characteristics, flexible configuration and easy installation and maintenance, it has become the preferred component for many engineers and system integrators around the world when designing and building motor control circuits.