Thermal overload relay for MC9b-40a series contactor, current 12-18A MT-32 9-13A

Motor protection with thermal overload relay MT-32

The MT-32 thermal overload relay is a reliable device used to protect electric motors from overload. Designed to work with MC series contactors, it provides effective protection against damage resulting from excessive load, phase failure, prolonged starting, or rotor blockage. It is a key element in securing the electrical installation, minimizing the risk of downtime and costly repairs.

Construction and application

The MT-32 relay is a bimetallic device, meaning it uses the thermal expansion of metals to detect overheating. If the set operating current is exceeded, the bimetal deforms, causing the control circuit to disconnect and the motor to shut down. This protects the motor windings from damage. This relay finds wide application in various industries, including HVAC systems, agricultural machinery, industrial equipment, and construction. It is compatible with MC-9b to MC-40a contactors.

Key features and benefits

• Wide adjustment range: The MT-32 relay offers a current adjustment range from 9A to 13A, allowing it to be adapted to different loads and motor powers.
• Direct mounting: The device is designed for direct mounting on the contactor, simplifying installation and saving space in the control cabinet.
• High reliability: Made of high-quality materials by the renowned manufacturer LS Electric (formerly LSiS), it ensures long-lasting and trouble-free operation.
• Compliance with standards: The relay meets the requirements of IEC/EN 60947-1 and IEC/EN 60947-4-1 standards, guaranteeing safety and compliance with applicable regulations.
• Versatility: Compatible with a wide range of MC-9b, MC-12b, MC-18b, MC-22b, MC-32a and MC-40a contactors – one device for many applications.
• Protection against various failures: Protects not only against overload, but also against phase failures and motor starting problems.
• Auxiliary contacts: Has built-in auxiliary contacts (1NO + 1NC) allowing signaling of relay operation and remote shutdown of the control circuit.

Technical data (summary)

• Current setting range: 9 - 13A
• Rated voltage Ue: 690V
• Insulation voltage: 690V
• Maximum impulse voltage Uimp: 6kV
• Protection class (according to IEC 60529): IP20
• Ambient temperature (operation): -25°C to +60°C
• Mounting method: Direct on contactor

The MT-32 thermal overload relay is an investment in the safety and reliability of electric motor operation – for both professional installers and end users.