ABB Thermal Overload Relay TA110DU110

The TA110DU110 is a classic 3-pole thermal overload relay from ABB TA series, delivering integrated protection for three-phase asynchronous motors with a rated current range of 80~110A. Adopting the inverse-time tripping principle of bimetallic strips, this relay comes standard with phase-loss protection and automatic ambient temperature compensation, with a trip class of Class 10A. It can be directly plugged onto ABB A/AE/AF95~110 series contactors or mounted independently on DIN rails. Equipped with switchable manual/automatic reset modes and one normally open (NO) plus one normally closed (NC) auxiliary signal contact, it serves as a standard protective component for industrial motor control circuits. Widely applied to power loads such as fans, water pumps, compressors and conveyor lines, it effectively prevents winding burnout accidents of motors caused by overload, locked rotor and phase loss.

Full Model: `TA110DU110`

1. TA: General series code for ABB thermal overload relays, representing the family of electrothermal protective relays
2. 110: Frame current rating, indicating the maximum rated frame current of 110A for this product
3. DU: Function type code, standing for standard specification featuring 3-pole protection, phase loss detection, ambient temperature compensation and direct mounting onto contactors
4. 110: Upper limit of current setting, corresponding to an adjustable current range of 80A ~ 110A

Core Technical Specifications

Cross Reference of Models within the Same Series

1. Full Specifications of TA110DU Frame

2. Comparison of Adjacent Frame Series

Typical Application Scenarios

1. Standard Motor Starter Protection Circuit: Combined with ABB A/AF series contactors to form electromagnetic starters, connected in series to the main circuit of three-phase motors to realize protection against motor overload, locked rotor and phase loss. It is the standard protection solution for general power equipment including fans, water pumps, air compressors and machine tool spindles.
2. MCC Motor Control Centers: Served as standard protection units for motor feeder circuits in drawer cabinets and fixed cabinets, integrated with contactors to realize integrated motor start-stop control and protection.
3. Conveyor & Logistics Sorting Systems: Matched with roller motors and sorting drive motors, adapting to frequent start-stop and load fluctuation working conditions of production lines, and preventing motor aging and burnout caused by long-term overload.
4. Central Air Conditioning & Refrigeration Units: Protect refrigeration power equipment such as compressors and cooling tower fans, suited to the refrigeration industry’s characteristics of severe load fluctuations and seasonal high-load operation.
5. Support for OEM Complete Equipment: Widely matched with industrial machinery including packaging machinery, rubber & plastic machinery and metallurgical auxiliary equipment. As standardized motor protection components, it meets electrical safety specification requirements for equipment factory delivery.

Common Troubleshooting Matrix

1. Terminal Definition & Function Description

The TA110DU110 adopts industry-standard terminal numbering rules, divided into two parts: main power circuit and auxiliary control circuit. All terminals are front-mounted screw-clamp type with all wiring operations accessible from the front side.

1. Main Circuit Terminals (Three-Phase Power Circuit)

Notes: The three-phase main circuit has no polarity requirement, yet each phase must be connected in one-to-one correspondence without cross-phase misconnection. When directly mounted on contactors, the main circuit is automatically conducted via plug-in copper bars with no extra power wiring required.

2. Auxiliary Circuit Terminals (Control & Signal Circuit)

The auxiliary contacts are electrically isolated with no electrical connection to the main circuit and a conventional thermal current of 5A. Intermediate relays are recommended for series connection to expand capacity and prevent contact burnout when controlling high-power loads.

1. Typical Wiring Schemes
2. Direct Mounting Wiring on Contactor (Most Commonly Used)

This is the standard application method for TA110DU110. It is directly plugged onto the top of ABB A95/A110/AF95/AF110 series contactors. The main circuit is automatically connected through internal plug-in connectors, with only the control circuit requiring external wiring:

1. Three-phase power passes through a circuit breaker and connects to contactor main incoming terminals L1/L2/L3
2. After the thermal overload relay is directly mounted on the contactor, the main circuit is automatically conducted without extra power wiring
3. One end of the control power supply passes through stop and start buttons and connects to contactor coil terminal A1
4. The 95-96 NC contact of the thermal relay is connected in series to the live wire of the contactor coil circuit to realize automatic motor shutdown under overload
5. The 97-98 NO contact of the thermal relay is paralleled with fault indicator lights or connected to PLC DI points for fault alarming
6. Independent DIN Rail Mounting Wiring

Independent rail mounting is adopted for separate installation or matching with contactors of other brands:

1. Contactor output terminals L1/L2/L3 are connected to thermal relay incoming terminals 1L1/3L2/5L3 via power cables
2. Thermal relay outgoing terminals 2T1/4T2/6T3 connect to motor three-phase terminals
3. The control circuit follows the same wiring logic as the direct mounting scheme, with the 95-96 NC contact wired in series into the contactor coil circuit

Wiring Precautions:

The cross-sectional area of main circuit cables shall match the 110A rated current; 25mm² copper cables are recommended

1~1.5mm² control cables are suggested for auxiliary control circuits

Reliable earthing is mandatory to guarantee personal and equipment safety

III. Parameter Comparison Table of Cross-Brand Equivalent Models

Below is a parameter comparison of mainstream thermal overload relays of the same current range from Siemens and Schneider Electric, for reference during alternative selection: