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1SVR740722R1400 ABB CM-MSS.21P Thermistor Motor Protection Relay
ABB CM-MSS.21P thermistor motor protection relay 1SVR740722R1400 with one PTC sensor circuit, short-circuit and interrupted-wire monitoring, 24–240 V AC/DC supply and one normally open plus one normally closed output contact.
£84.32
Why Choose the ABB CM-MSS.21P Thermistor Motor Protection Relay?
The ABB CM-MSS.21P is a compact and reliable thermistor motor protection relay designed to monitor PTC temperature sensors installed in electric motor windings. Supplied under ABB order code 1SVR740722R1400, it belongs to the ABB CM-MSS thermistor motor protection relay series and provides direct thermal supervision to help protect motors against damaging overtemperature conditions.
The CM-MSS.21P features one sensor circuit with short-circuit detection and dynamic interrupted-wire monitoring. It operates according to the closed-circuit principle and incorporates non-volatile fault storage, providing dependable supervision of both motor temperature and the integrity of the connected PTC sensor circuit.
Operating from a wide 24–240 V AC/DC control supply, the CM-MSS.21P provides one normally open and one normally closed output contact, with contacts rated at 250 V / 4 A. Automatic reset, ATEX approval and maintenance-free Easy Connect push-in terminals make it well suited to industrial motor control centres, machinery and electrical control panels.
Key Advantages
- Reliable PTC thermistor motor temperature monitoring.
- One sensor circuit for direct motor winding temperature supervision.
- Short-circuit detection provides additional sensor-circuit monitoring.
- Dynamic interrupted-wire detection helps identify sensor wiring faults.
- Non-volatile fault storage supports dependable fault monitoring.
- Automatic reset after the monitored fault condition has been removed.
- Wide 24–240 V AC/DC control supply supports flexible integration.
- 1 normally open + 1 normally closed contact for signalling and control.
- ATEX-approved thermistor motor protection functionality.
- Maintenance-free Easy Connect push-in terminals simplify panel wiring.
Key Features
- ABB CM-MSS thermistor motor protection relay series.
- ABB order code 1SVR740722R1400.
- One PTC temperature sensor circuit.
- Short-circuit monitoring of the sensor circuit.
- Dynamic interrupted-wire monitoring.
- Non-volatile fault storage.
- Automatic reset operation.
- Operates according to the closed-circuit principle.
- 24–240 V AC/DC rated control supply voltage.
- 1 n/o + 1 n/c output contact.
- Output contacts rated at 250 V / 4 A.
- ATEX approved.
- Push-in / screwless terminal technology.
- Compact 22.5 mm DIN rail housing.
Reliable PTC Thermistor Protection for Electric Motors
PTC temperature sensors embedded within motor windings provide direct thermal supervision by changing resistance as the winding temperature approaches the sensor response point. The ABB CM-MSS.21P evaluates the connected PTC circuit and changes the state of its output contacts when an overtemperature condition is detected, allowing the associated control circuit to stop the motor or initiate an alarm.
In addition to temperature monitoring, the CM-MSS.21P supervises its sensor circuit for short circuits and interrupted wiring. Automatic reset allows the relay to return to its normal operating state after the fault condition has been removed, making it a practical solution for dependable industrial motor thermal protection.
Typical Applications
- Industrial motors equipped with PTC temperature sensors.
- Pumps, fans and ventilation equipment.
- Compressors and refrigeration machinery.
- Conveyors and material handling systems.
- Machine tools and production machinery.
- Motor control centres and electrical control panels.
- Industrial installations requiring ATEX-approved thermistor motor protection.
Technical Specifications
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| Reset Type | Automatic | |
|---|---|---|
| Monitoring Function | Temperature / thermistor | |
| Series | CM-MSS | |
| ABB order code | 1SVR740722R1400 | |
| Product group | 310921-Measuring & Monitoring Relays | |
| Product type | Thermistor motor protection relay | |
| Sensor type | PTC temperature sensors | |
| Number of sensor circuits | 1 | |
| Operating principle | Closed-circuit principle | |
| Short-circuit detection | Yes | |
| Interrupted-wire detection | Dynamic | |
| Fault storage | Non-volatile | |
| Reset function | Automatic | |
| Rated control supply voltage | 24–240 V AC/DC | |
| Outputs | 1 normally open + 1 normally closed contact | |
| Contact rating | 250 V / 4 A | |
| Maximum output circuit operating voltage UL/CSA | 300 V AC | |
| UL/CSA contact rating | B300 | |
| Terminal type | Screwless push-in terminals | |
| Approval | ATEX approved | |
| Operating temperature | -25 to +60 °C | |
| Storage temperature | -40 to +85 °C | |
| Mounting | DIN rail | |
| Width | 22.5 mm | |
| Height | 85.6 mm | |
| Depth | 103.7 mm | |
| Net weight | approx. 0.118 kg | |
| EAN / UPC | 4013614496516 |
Frequently Asked Questions
What is the ABB CM-MSS.21P used for?
The CM-MSS.21P is used to monitor PTC temperature sensors installed in electric motor windings, helping protect motors against excessive operating temperatures.
How many sensor circuits does the CM-MSS.21P have?
The CM-MSS.21P provides one PTC temperature sensor circuit with short-circuit and dynamic interrupted-wire monitoring.
What supply voltage does the CM-MSS.21P require?
The CM-MSS.21P operates from a wide 24–240 V AC/DC control supply.
What outputs does the CM-MSS.21P provide?
The relay provides one normally open and one normally closed output contact, with contacts rated at 250 V / 4 A.
Does the CM-MSS.21P monitor thermistor wiring faults?
Yes. The CM-MSS.21P provides short-circuit detection and dynamic interrupted-wire detection for supervision of the connected PTC sensor circuit.
Trusted ABB Motor Protection Technology
ABB CM-MSS thermistor motor protection relays provide dependable PTC temperature monitoring and sensor-circuit supervision to help protect electric motors in industrial machinery, automation and motor control applications.
