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Thermistor overload relay ABB CM-MSS
Thermistor motor protection relay 24V AC/DC
1 switch
Item No. 4036.7077
Features of ABB CM-MSS
- 1 measuring circuit
- Automatic reset
- Overvoltage-protected power supply and measurement inputs
- Increased immunity to interference according to EN 62061 with evaluation criterion "Fail-Safe"
- Enclosure material with max. fire protection class UL 94 V-0
- Tool-free mounting and dismounting on DIN rail
- Screw connection
- Width 22.5mm (0.89 inch)
- For rail width 35mm
- UL 508, CAN/CSA C22.2 No.14, IEC/EN 60947-5-1, IEC/EN 60947-8
Versions
| Item No. | Manufacturer ID | Delivery Time | Stock | Quantities / Prices |
|---|---|---|---|---|
| 4036.7077 | 1SVR730700R0100 | 1 day(s) | 7 |
Technical Features
Series Specifications
Individual Parameters
Rated control supply voltage
24V AC/DC
Type
CM-MSS.12s
Manufacturer
ABB STOTZ-KONTAKT GmbH, Eppelheimerstr. 82, DE - 69123 Heidelberg
Functionality and application possibilities
Thermistor Motor Protection Relay - Benefits and Advantages, Applications
The CM-MSx series thermistor motor protection relays protect motors with PTC temperature sensors against high temperatures. The temperature sensors are integrated into the motor windings, allowing them to directly measure motor heating.
Direct Temperature Measurement
In general, motor damage caused by overload or overheating can be prevented in various ways. Compared to indirect temperature measurement, which monitors the current flowing in the motor, the temperature inside the motor can be measured through direct temperature measurement. This allows for the direct control and evaluation of the following operating conditions:
Therefore, the effects of overheating, such as wear and electrical failures, can be avoided.
The direct measurement principle involves a combination of the thermistor motor protection relay and 3 PTC sensors that are directly installed by the manufacturer in the motor. These 3 PTC sensors are placed directly at the thermally hot spots, the motor windings.
Motor Monitoring
The thermistor motor protection relay measures the resistance of the PTC sensors, which indicates the internal motor temperature at any time. If the temperature in the motor winding rises excessively and
the rated response temperature (NAT) is reached, the thermistor motor protection relay detects this condition, and the output relay switches off.
This triggers the motor protector and disconnects the motor.
Application / Monitoring Function
The thermistor motor protection relay CM-MSS monitors the winding temperature and thus protects the motor against overheating, overload, and inadequate cooling according to the product standard IEC 60947-8, control units for built-in thermal protection (PTC) for rotating electrical machines.
Operation
The thermistor motor protection relays CM-MSS.12 and CM-MSS.13 are used to monitor the temperature of motors or generators equipped with PTC thermistor sensors (PTC temperature sensors) type A. The sensors are installed in the motor windings and measure the heating of the motor. As the temperature in the motor increases, the resistance in the PTC sensor also rises. If the motor overheats (>2.7 kO), the output relay drops out, and the corresponding LED signals overtemperature. A reset is only possible after the motor has cooled down (<1.2 kO).
Reset
Once a fault has been corrected and the measurement value has fallen below the reset condition limit, an automatic reset is performed.