Phase failure and asymmetry sensor, 2NO/NC contact, DIN rail mounting CZF-331

Motor protection sensor – protection against phase failure and voltage asymmetry

This phase sensor, model CZF-331, is a reliable device designed to protect three-phase powered electric motors. Its function is to detect voltage loss in one or more phases and voltage asymmetry, which can lead to motor damage. DIN rail mounting simplifies installation in electrical panels.

Functionality and application

CZF-331 continuously monitors the voltage state in the network. If an irregularity is detected – phase failure or excessive asymmetry – the circuit is disconnected, protecting the motor from potential failure. A 4-second disconnection delay minimizes the risk of unnecessary motor disconnection during momentary voltage drops. After the correct power supply parameters are restored, the device automatically switches the circuit on. This ensures continuous operation and increases the safety of the installation.

Key features:

• Phase failure protection: Reacts to the absence of voltage in any phase, preventing motor damage.
• Voltage asymmetry control: Detects uneven phase loading, which can lead to overheating and motor failure.
• Two changeover contacts (2NO/NC): Allow connection of additional signaling or control devices, informing about the system's operating status. They can be used to activate an alarm or disconnect other installation elements.
• Adjustable trigger threshold: Allows adaptation of the sensor's sensitivity to specific installation operating conditions.
• DIN rail mounting: Quick and easy mounting in standard electrical panels.
• Wide voltage range: Designed for operation in networks with a voltage of 3x400V + N.

Technical parameters and construction

The device is characterized by a solid construction and high reliability. It has screw terminals with a cross-section of 4.0 mm², ensuring safe and durable electrical connections. LED indicators signal the device's power status. CZF-331 occupies 3 modules on the DIN rail (52.5 mm wide). The maximum contact load current is 8A, allowing control of various loads. The device operates in a temperature range from -25°C to 40°C and has a protection class of IP20. The contacts used are galvanically isolated for increased safety. The voltage measurement range is 140...270V, and the voltage hysteresis is 5V, ensuring stable operation of the device in variable network conditions.