PKF-333 type relays are designed for control of voltages in one-phase and three-phase networks. They find application in systems of automatic spare capacity activation and also in protection of induction motors from damage due to voltage drop or failure and angular voltage unbalance. They are among the few relays on the market featuring the full phase control over supply voltage.

Automatic reserve activation systems, 3-phase undervoltage and overvoltage relay

• one overvoltage channel
• one undervoltage channel
• range of nominal voltages: 3 x (50...265)V
• supply voltage phase unbalance control
• True RMS voltage measurement
• phase sequence detection
• two independent relay outlets: switch contacts
• relay actuation signalled with LED
• dimensions: 54 x 90 x 58mm

Adjustable parameters:

• drop-out voltage Uo
• recovery voltage Up
• drop-out time To
• recovery time Tp
• phase angle variation

Protection of motors, 3-phase overvoltage relay

• one overvoltage channel
• one undervoltage channel
• range of nominal voltages: 3 x (50...265)V
• supply voltage phase unbalance control
• True RMS voltage measurement
• phase sequence detection
• two independent relay outlets: switch contacts
• relay actuation signalled with LED
• dimensions: 54 x 90 x 58mm

Adjustable parameters::

• drop-out voltage Uo
• recovery voltage Up
• drop-out time To
• recovery time Tp
• phase angle variation

Protection of three-phase motors

• one overvoltage channel
• fixed actuation setpoints and drop-out and recovery times
• one relay outlet: switch contacts
• relay actuation signalled with LED
• dimensions: 36 x 90 x 58mm