Phase failure sensor with contactor monitoring CZF-332 contacts: 1P separated, I=10A, 3 modules

Motor and installation protection – phase failure sensor CZF-332

CZF-332 is a reliable phase failure sensor with an additional contactor contact monitoring function. The device is designed to protect electric motors powered from a three-phase network against the effects of voltage loss in one or more phases, phase-to-phase voltage asymmetry, and contactor contact failure. This is a comprehensive solution that minimizes the risk of failure and extends the life of connected devices.

Functionality and application

The sensor reacts to irregularities in the power supply, such as voltage loss or asymmetry, by switching off the motor with a 4-second delay. This delay prevents accidental disconnection of the motor during short-term voltage drops that may occur in the network. Additionally, the sensor continuously monitors the status of the contactor contacts that switch on the motor. If their damage is detected, the circuit is permanently switched off – which is crucial to avoid more serious failures and costly repairs. Restarting the motor after an intervention related to contactor damage requires manual reset after the fault is removed.

Construction and characteristic features

CZF-332 is mounted on a standard 35 mm rail and occupies 3 modules (52.5 mm wide). It has screw terminals with a cross-section of 4.0 mm², providing solid and secure electrical connections. LED indicators inform about the power supply status and device operation. The device does not require an external power source, drawing energy directly from the monitored circuit. The used relay has one changeover contact NO/NC with a maximum load current of 10A, ensuring compatibility with various types of loads. The sensor effectively detects voltage asymmetry in the range of 40-80V and has a voltage hysteresis of 5V. This ensures precise and stable operation in changing network conditions.