Microprocessor phase sequence and phase failure sensor CKF-TRMS

Intelligent three-phase motor protection – phase sequence and loss sensor CKF-TRMS

This microprocessor-based phase sequence and loss sensor is a reliable solution for protecting electric motors powered by a three-phase network. The device monitors the voltage continuity in each phase and detects voltage asymmetry, protecting the motor from damage caused by the absence of one phase or uneven load. This allows the installer to be sure that the motor operates under safe conditions, and the end user avoids costly downtime and repairs.

The CKF-TRMS sensor stands out for its measurement accuracy thanks to True RMS technology, which guarantees correct operation even in power networks with high interference. This is particularly important in industrial environments where the power supply quality often deviates from ideal parameters. Additionally, the sensor controls the phase sequence, preventing unwanted changes in the motor's direction of rotation.

Functionality and application

The device is designed for surface mounting and is characterized by compact dimensions (51x67x26 mm). Its operation is based on the immediate detection of voltage loss in any phase or exceeding the voltage asymmetry threshold (45V). In the event of a detected irregularity, the circuit is disconnected with a 4-second delay – this prevents accidental disconnection of the motor during momentary voltage drops. Automatic restart occurs after the correct power parameters are restored (voltage increase of 5V above the trigger value).

• Phase loss protection: Protects the motor from damage in the event of the absence of one of the supply phases.
• Voltage asymmetry control: Protects against uneven phase loading, which can lead to overheating and motor failure.
• Phase sequence control: Prevents the motor from starting in an unwanted direction of rotation.
• True RMS measurement: Ensures accurate measurements even in disturbed power networks.
• Adjustable time delay: The 4-second shutdown delay minimizes the risk of false alarms.

The sensor has one NO (normally open) changeover contact with a maximum load current of 10A and is made in screw connection technology. It does not require an external power source and works with networks with a voltage of 190-270V. This makes installation simple and quick, and the device is ready to use immediately after connection.