ABB TF42-0.74 Thermal Overload Relay, Trip Class 10, 0.55-0.74 A, 3-Pole, 1NO+1NC

Electric motors are vulnerable to overheating when overloaded, and without reliable protection, costly downtime and damage are inevitable. The ABB TF42-0.74 thermal overload relay solves this by monitoring motor current and disconnecting the circuit when an overload persists beyond the safe time limit. Set for a current range of 0.55–0.74 A and trip class 10, it offers precise protection for small three-phase motors, ensuring they operate within thermal limits.

Who is it for

This relay is intended for panel builders, maintenance engineers, and OEMs who need dependable motor protection in industrial control systems. It is particularly suitable for applications with small motors such as pumps, fans, conveyors, and machine tools, where space is limited and reliability is critical.

Main features

• Adjustable current setting from 0.55 A to 0.74 A for precise overload protection.
• Trip class 10 ensures fast disconnection on overload, protecting motor windings.
• Three-pole design for balanced protection of three-phase motors.
• Auxiliary contacts: 1 NO + 1 NC for signaling and control circuit integration.
• Manual and automatic reset modes for flexible operation.
• Direct mounting on ABB AF09...AF38 contactors or standalone via screw terminals.
• IP20 protection, suitable for installation in enclosed control panels.
• Complies with international standards IEC/EN 60947-1, 60947-4-1, 60947-5-1, and UL/CSA.

Specifications

• Rated operational current range: 0.55–0.74 A
• Trip class: 10
• Number of poles: 3
• Auxiliary contacts: 1 NO + 1 NC
• Rated operational voltage (Ue): 690 V AC
• Rated insulation voltage (Ui): 690 V
• Rated impulse withstand voltage (Uimp): 6 kV
• Rated frequency: 50/60 Hz
• Mounting: direct to contactor or standalone
• Compatible contactors: ABB AF09, AF12, AF16, AF26, AF30, AF38
• Reset type: manual and automatic
• Degree of protection: IP20
• Ambient operating temperature: -25 to +60 °C
• Ambient storage temperature: -50 to +80 °C
• Terminal type: screw terminals
• Power loss per pole: 1.5 W
• Standards: IEC/EN 60947-1, IEC/EN 60947-4-1, IEC/EN 60947-5-1, UL/CSA

Tips

When installing, ensure the relay is set to the motor's full load current (FLC) within the 0.55–0.74 A range. For automatic reset applications, verify that the control circuit can safely handle automatic restart. Always mount the relay in a clean, dry enclosure to maintain IP20 protection.