Thermal overload relay for MC9b-40a series contactor, current 0.25-0.4A MT-32 28-40A

Motor and Circuit Protection – Thermal Relay MT-32

The MT-32 thermal relay with a current setting range of 28-40A is a reliable device used to protect electric motors and circuits from the effects of overloads, phase asymmetry, prolonged starts, and rotor blockage. It provides effective protection against damage resulting from improper operating conditions, which translates to a longer lifespan of devices and minimization of downtime.

Application and functionality

The MT-32 relay utilizes bimetallic technology that reacts to temperature increases caused by excessive current flow. If the set value is exceeded, the bimetal deforms, causing the disconnecting mechanism to release. This disconnects the motor from the power supply before it overheats and is damaged. The device is compatible with MC-9b, MC-12b, MC-18b, MC-22b, MC-32a and MC-40a series contactors.

Construction and characteristic features

The MT-32 relay is characterized by a compact design and easy installation – it can be mounted directly under the contactor or using a dedicated mounting base UZ-63L (available separately). It has one normally open (NO) auxiliary contact and one normally closed (NC) auxiliary contact, which allows for signaling the device status and integration with control systems. Made of high-quality materials, it ensures durability and reliable operation even in harsh industrial conditions. It meets IEC/EN 60947-1 and IEC/EN 60947-4-1 standards and has CE, CSA, UL and CCC certificates.

Key features:

• Current setting range from 28 to 40 A.
• Possibility of operation at rated voltage AC up to 690 V.
• Rated insulation voltage reaches 690 V.
• Adapted to work in networks with a frequency of 50/60 Hz.
• Equipped with NO and NC auxiliary contacts for status signaling.
• Possibility of direct mounting or on UZ-63L base.
• Wide range of ambient temperatures during operation (up to +60°C depending on the model).
• Device weight is approximately 0.17 kg.
• Main circuit connection realized by screw connection (18AWG / 1mm² wires).

This thermal relay is a solid solution for installers and users looking for reliable protection of electric motors in various industrial applications.