Phase Protection Relay - FKV-24F | TENSE

The FKV series phase protection relays are designed to protect three-phase equipment, especially motors, from faults related to incorrect voltage value, asymmetry, phase failure, or incorrect phase sequence. The FKV-24F operates in a wide range of 180-500 VAC and has a fixed asymmetry of 11%.

It ensures reliable operation of equipment with high demands for power accuracy and protects them from thermal and mechanical damage.

Functions and Operating Principle

Voltage Asymmetry (11%)

• Monitors the difference between phase voltages.

• If the asymmetry exceeds 11%, the relay disconnects the output after approx. 1s and opens the NO/COM contacts.

• When the difference drops below 5V, the relay evaluates the condition as normal and resumes output after a delay period.

Phase Sequence Check

• Correct phase sequence → OUT LED on, output active (NO connected).

• Incorrect phase sequence → LED turns off and output goes into fault state.

Overvoltage Protection (U>)

• If the voltage exceeds 500V, the overvoltage indication is activated.

• If the condition lasts for more than 2s, the relay disconnects the output.

• When the voltage drops 5V below the U> limit, the relay starts a delay countdown and then resumes operation.

Undervoltage Protection (U<)

• If the voltage drops below 180V, the undervoltage indication is activated.

• If the condition does not end during the error delay, the output will shut off.

• When the voltage rises 5V above U<, the relay reactivates the output after a delay period.

Status Indications

• 5 LEDs provide information about:

  • relay status (OUT)

  • overvoltage (U>)

  • undervoltage (U<)

  • phase sequence

  • asymmetry / fault

Key Features

• Wide operating voltage range: 180-500 VAC

• Fixed asymmetry: 11%

• Protection against:

  • Undervoltage

  • Overvoltage

  • Asymmetry

  • Phase sequence errors

  • Phase failure

• No neutral conductor needed

• Fast response to fault conditions (approx. 1s)

• LED indication for all functions

• Suitable for motors, compressors, pumps, and other three-phase loads

Technical Parameters