Phase sequence and phase failure sensor CKF contacts: 1Z, I=10A, hermetic enclosure, connection lead

Phase sequence and phase failure sensor – reliable motor protection

This phase sequence and phase failure sensor is a key element in protecting three-phase powered electric motors. Its function is to monitor the presence of all phases and detect voltage imbalances that can lead to motor damage or incorrect direction of rotation. The device is particularly useful in industrial applications, but will also work wherever high reliability and protection against failures are required.

Functionality and application

The sensor effectively protects motors against the effects of phase loss or voltage asymmetry between phases. Additionally, it protects against starting the motor in an unwanted direction, which can occur when the phase sequence is reversed. This minimizes the risk of downtime and costly repairs. It finds application in motor controllers, electrical switchboards and all kinds of installations powering three-phase devices.

Operating characteristics and construction

The device operates on the principle of continuous monitoring of voltages in individual phases. In the event of a detected irregularity – phase loss or exceeding the permissible asymmetry (above 55V~) – the circuit is disconnected with a delay of 4 seconds. This delay prevents accidental disconnection of the motor during short-term voltage drops. A built-in NO (normally open) contact with a capacity of up to 10A allows easy integration of the sensor into existing control systems. Made of high-quality materials, with a hermetic housing, ensures durability and resistance to environmental conditions. Mounting is done on a standard TH-35 rail, which facilitates integration with existing infrastructure. The operating status is indicated by two LEDs: green (correct phase sequence) and red (incorrect phase sequence). The absence of both LEDs indicates a phase failure or excessive voltage asymmetry.