ABB CM-MSS Thermistor Motor Protection Relay

Description

The ABB CM-MSS is a high-performance thermistor motor protection relay designed for monitoring PTC temperature sensors. It reliably prevents thermal overloading of motors by tripping when the nominal response temperature is exceeded. This unit features a wide and versatile supply voltage range from 24 to 240V AC/DC, making it suitable for a vast array of industrial applications worldwide. Its compact design allows for easy DIN-rail installation in control cabinets.

Specifications

• Manufacturer: ABB
• Type: CM-MSS
• Order Code: 1SVR430720R0400
• Supply Voltage: 24-240V AC/DC (15-400Hz)
• Output Contacts: 1 NO / 1 NC
• Rated Switching Current (AC15): 3A at 230V
• Rated Switching Current (DC13): 2A at 24V
• Indicators: LEDs for supply voltage (U) and fault (F)
• Mounting: DIN Rail

Label Info

• Ithe: 4A
• Ui: 250V
• Uimp: 4kV
• ATEX Certification: PTB 02 ATEX 3080, II (2) G D

Application

Ideal for protecting motors in conveyors, pumps, fans, and compressors, especially in environments requiring ATEX-certified components such as the chemical, oil and gas, or food processing industries.

Country of Origin

Made in Germany.

CO2 Impact

Choosing this pre-owned component over a new one saves approximately 4.8 kg of CO2 emissions, a significant contribution to sustainable industrial practices.

Availability

This item is in stock and ready for immediate dispatch. Order now from PLC2Day for expert support and fast delivery.

FAQ

Question?

Can the CM-MSS distinguish between a short-circuit and an open-circuit in the thermistor sensor loop?

Yes, the CM-MSS is designed to detect both conditions. A flashing red 'F' LED indicates a short-circuit, while a permanently lit red 'F' LED after a fault indicates an open-circuit or over-temperature condition.

Is this relay suitable for use in explosive atmospheres, and what are its limitations?

Yes, it has an ATEX certification (PTB 02 ATEX 3080) for category II (2) G D, making it suitable for zones with gas (G) and dust (D) explosion hazards. However, it must be installed according to the specific ATEX directives and used with certified PTC sensors.

What is the function of the 'Reset/Test' button and can the reset be automated?

The front-face button allows for a manual reset after a fault has been cleared and also for testing the relay's function. For automated or remote reset, you can connect a normally open push button across terminals T1 and T2.

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Friday, March 13, 2026