The thermistor motor protection relays CM-MSE, CM-MSS and CM-MSN are used to control motors equipped with PTC temperature sensors. The PTC temperature sensors are incorporated in the motor windings to measure the motor heating. This enables direct control and evaluation of various operating conditions. Depending on the products also ATEX approvals for use in hazardous areas are availabe.
ABB also offers PTC temperature sensors C011 (according to DIN 44081) which are suitable for embedding in motor windings.
CM-MSE single function thermistor motor protection relay
The single function relays are equipped with 1 n/o output contact in a 22.5 mm wide enclosure and they are supplied with a single voltage range.
CM-MSS universal thermistor motor protection relay
Depending on the device refences with 1 c/o (SPDT) contact, 2 x 1 c/o (SPDT) contact, 2 c/o (SPDT) contacts or 1 n/c + 1 n/o contact are available. Products can be selected with wide- or single-supply voltage range, short-circuit monitoring of the sensor circuit, front-face test and reset button, Non-volatile storage configurable, 1- or 2-channel evaluation or accumulative evaluation, up to 3 sensor circuits. As for all products in the S-range assortment LEDs for status indication are included in the 22.5 mm wide housing with integrated and snap-fitted front-face marker. As accessories sealable transparent cover and adapter for screw mounting can be ordered.
CM-MSN thermistor motor protection relay for six sensor ciruits
The CM-MSN relays offer the highest functionality in a 45mm housing:
- 1 n/c + 1 n/o contact
- Wide supply voltage range
- Short-circuit monitoring of the sensor circuit
- Front-face test and reset button
- Non-volatile storage configurable
- Accumulative evaluation, up to 6 sensor circuits
- Integrated and snap-fitted front-face marker
- Sealable transparent cover (accessory)
- Adapter for screw mounting (accessory)
- Standard version acc. to DIN 44081 or triple temperature sensor
- For motors with rated operational voltages of up to 660 V AC
- Response temperatures from 70 °C to 170 °C, depending on sensor
- Conductor length 5 m
Examples of application
Protection of motors against thermal overload, e. g. caused by insufficient cooling, heavy load starting conditions, undersized motors, increased switching frequency, single-phase operation, high ambient temperature, break operation, unbalance, etc.