FF phase sequence and phase loss relay CKF-337 1P 10A 0.2–5 s 20–60 V

FF phase sequence and phase loss relay CKF-337 1P 10A 0.2–5 s 20–60 V is a compact electromechanical/electronic device designed to monitor three-phase supply conditions in single-pole installations. It detects incorrect phase rotation, phase loss and significant phase unbalance, and switches output contacts to protect motors and other three-phase loads. The unit accepts control voltages in the 20–60 V range and provides a switching capacity suitable for direct control of small contactors and loads up to 10 A, with an adjustable response delay between 0.2 and 5 seconds.

Advantages

The relay combines electromechanical reliability with electronic adjustment, offering clear detection of phase sequence errors and phase loss while allowing a selectable time delay to prevent nuisance tripping on transient events. Its single-pole (1P) configuration simplifies installation in control circuits and distribution panels, and the rated switching current up to 10 A supports a broad range of protection and control applications. The compact form factor and straightforward adjustment make it practical for retrofits and new installations where space and simplicity are important.

Suitable for

• Protection of three-phase motors against reversed phase rotation
• Detection of phase loss or phase unbalance in small distribution panels
• Control circuits for contactors and starters in industrial and commercial equipment
• Applications requiring low-voltage monitoring within 20–60 V supply systems

Key specifications

• Operating function: phase sequence detection and phase loss protection
• Poles: single-pole (1P)
• Supply voltage range: 20–60 V
• Adjustable time delay: 0.2–5 s
• Switching current: up to 10 A
• Combined electromechanical/electronic design for reliable switching and adjustment

How to use

Mount the relay in the control panel or on a DIN rail according to the installation instructions for single-pole devices. Connect the three-phase sensing inputs and the low-voltage supply within the specified 20–60 V range, and wire the output contact to the motor starter or load circuit rated for the relay's 10 A switching capacity. Set the desired time delay between 0.2 and 5 seconds to prevent tripping during short transients. Verify correct phase rotation and perform a functional test before placing the protected equipment into normal operation.

Usage recommendations

Use the relay with loads and contactors that do not exceed the 10 A switching rating, and ensure supply voltage remains within 20–60 V. Select a time delay sufficient to ignore brief voltage dips but short enough to protect equipment from prolonged phase faults. Periodically inspect connections and test the device as part of routine maintenance to ensure continued protection of motors and three-phase equipment.