ABB TF42-38 Thermal Overload Relay, 30-38 A, Class 10, 3-Pole, 690 V AC, 1NO+1NC

Motor burnout from overloads is a constant threat in industrial settings, causing costly downtime and repairs. The ABB TF42-38 thermal overload relay directly addresses this risk by monitoring motor current and disconnecting power when an overload or phase loss occurs. With a setting range of 30–38 A and Class 10 tripping, it protects three-phase motors up to 690 V AC, ensuring reliable operation and extended equipment life.

Who is it for

This relay is ideal for panel builders, maintenance technicians, and OEMs who need dependable motor protection in industrial control systems. It is particularly suited for applications using ABB AF series contactors (AF09 to AF38), where direct mounting simplifies installation and reduces wiring.

Main features

• Adjustable current setting from 30 A to 38 A for precise protection.
• Tripping Class 10 ensures fast response to overloads, minimizing motor stress.
• Three-pole design with phase loss sensitivity protects against single-phasing.
• Manual and automatic reset modes for flexible operation.
• Temperature compensation from -20 °C to +60 °C maintains accuracy across ambient conditions.
• Auxiliary contacts (1 NO + 1 NC) for signaling and control integration.
• Complies with IEC/EN 60947-4-1, UL, and CSA standards for global acceptance.

Specifications

• Rated operational current setting range: 30–38 A
• Tripping class: 10
• Number of poles: 3
• Rated operational voltage (Ue): 690 V AC
• Rated insulation voltage (Ui): 690 V AC
• Rated impulse withstand voltage (Uimp): 6 kV
• Auxiliary contacts: 1 NO + 1 NC
• Reset type: Manual and automatic
• Temperature compensation: Yes (-20 to +60 °C)
• Ambient operating temperature: -25 to +60 °C
• Degree of protection: IP20
• Mounting type: Direct mounting to contactor / Stand-alone with accessory
• Compatible contactors: ABB AF09, AF12, AF16, AF26, AF30, AF38
• Standard compliance: IEC/EN 60947-4-1, UL 60947-4-1, CSA C22.2 No. 60947-4-1
• Overload protection type: Thermal
• Phase loss sensitivity: Yes

Tips

For reliable operation, ensure the relay is mounted in an environment within the specified temperature range and protected from dust and moisture (IP20). When using with ABB AF contactors, direct mounting reduces installation time and potential wiring errors. Always set the current adjustment to match the motor's full load current to achieve optimal protection.