Phase sequence, phase loss and asymmetry relay FF CKF-B 10A 1-pole 4 s 55 V

Electromechanical relay FF CKF-B monitors phase sequence, phase loss and phase asymmetry in three-phase electrical systems. The device is intended for installation in control panels and motor protection circuits and provides a single normally open contact for signaling or interlocking. Rated for currents up to 10 A and designed to operate from a 55 V supply, the relay includes an adjustable response time of 4 seconds to prevent nuisance trips on short disturbances.

Advantages

This relay combines simple electromechanical construction with clear functional monitoring of phase order, phase absence and voltage imbalance. The single normally open contact enables straightforward integration with starters, contactors or alarm circuits. An adjustable delay of up to 4 seconds reduces false operations from transient events. The compact, DIN-rail compatible form factor facilitates installation in industrial and commercial control cabinets.

Suitable for

• Protection of three-phase motors against incorrect phase sequence
• Prevention of equipment operation during phase loss
• Monitoring voltage asymmetry in distribution and control systems
• Integration with motor starters, contactors and interlock circuits

Key specifications

• Function: phase sequence detection, phase loss detection, phase asymmetry monitoring
• Contact configuration: 1 normally open contact (1-pole)
• Rated switching current: up to 10 A
• Operating supply voltage: 55 V
• Adjustable response (delay) time: up to 4 s
• Type: electromechanical relay suitable for DIN-rail or panel mounting

How to use

Install the relay in the control cabinet and connect the three-phase supply and the relay coil according to the wiring diagram supplied with the device. Wire the normally open contact into the starter or alarm circuit that must be opened when a phase fault is detected. Set the response-time adjustment to a value that filters short transients but reacts to sustained phase faults; typical settings depend on system dynamics and starting currents. After wiring, perform a functional test by simulating phase loss, reversed phase sequence and asymmetric voltages to confirm correct operation.

Usage recommendations

Use the adjustable delay to balance sensitivity and immunity to transient disturbances; verify compatibility with motor starting characteristics and coordinate with upstream protection devices. Ensure the relay is mounted in a ventilated panel environment and that terminal connections are tightened to the manufacturer’s recommended torque values.