METZ CONNECT Thermistor Relay TMR-E12, 24V AC/DC, 2W, without fault memory 1103151322

Electric motors are the workhorses of industry, but they can overheat due to overload, locked rotor, or insufficient cooling. The METZ CONNECT TMR-E12 thermistor relay provides reliable motor overheat protection by monitoring PTC thermistor sensors embedded in the motor windings. When the winding temperature exceeds a safe threshold, the relay trips and opens its output contact, cutting power to the motor contactor and preventing damage. With automatic reset and no fault memory, the relay is ideal for applications where manual intervention is not required and the motor can restart once it cools down.

Who is it for

This thermistor relay is designed for electrical engineers, panel builders, and maintenance technicians who need compact and dependable motor protection in industrial control systems. It is suitable for protecting three-phase motors in pumps, fans, compressors, conveyors, and other machinery where overheating is a risk. Its DIN rail mounting and screw terminals make it easy to integrate into control cabinets.

Main features

• Monitors up to 6 PTC thermistor sensors connected in series
• 1 changeover contact (SPDT) for flexible control wiring
• Automatic reset when motor cools down (no fault memory)
• Wide operating voltage range: 24V AC/DC
• Compact design: only 22.5 mm wide (1 module)
• LED indicator for relay status
• IP20 protection for control cabinet installation

Specifications

• Product type: Thermistor relay
• Operating voltage: 24V AC/DC
• Power consumption: 2 W
• Output contact: 1 changeover (SPDT)
• Max switching voltage: 250V AC
• Max switching current: 5A (resistive load)
• Trip resistance: ≤ 3.6 kΩ
• Reset resistance: ≥ 1.6 kΩ
• Number of PTC inputs: 1 (up to 6 sensors in series)
• Mounting: 35mm DIN rail
• Connection: Screw terminals
• Operating temperature: -25°C to +55°C
• Dimensions (HxWxD): 90 x 22.5 x 60 mm
• Certifications: CE

Tips

Ensure that the PTC thermistor sensors used are compliant with DIN 44081/44082 standards for correct tripping behaviour. The relay's automatic reset function means the motor may restart unexpectedly after cooling; implement additional safety measures if this poses a risk. For manual reset or fault indication, consider the TMR-E12 version with fault memory.