Three-phase monitoring/protection relay for phase failure/asym/over-pump control

Phase protective relays are designed to protect devices with precise values operating voltage and phase switching functions before errors that may occur in due to the network voltage and the temperature of the motor.

FKV-24F has a constant asymmetry of 11%. It can operate at a voltage from 180 to 500 V AC.

Asymmetry means the difference between voltage values. Especially in three-phase loads, such as motors, the high-voltage coil consumes a large current and the low-voltage coil low voltage. Therefore, they operate unbalanced and the coils get damaged over time.

When there is the device is turned on, contacts of the relay no. 1 (NC) and 2 (COM) are closed and contacts no. 2 (COM) and 3 (NO) are open. If the voltage values are in normal range, the LED (OUT) in the relay will light up; the terminals of relay 1 (NC) and 2 (COM) are open, the terminals of relay 2 (COM) and 3 (NO) are closed.

If if the difference between the voltage values exceeds 11 %, the relay LED will turn off after approximately 1 second and the contacts of relay 1 (NC) and 2 (COM) will close and the contacts of relay 2 (COM) and 3 (NO) will disconnect. If the difference between the voltage values decreases by 5 V, the relay LED will light up and the contacts of relay 1 (NC) and 2 (COM) will disconnect and the contacts of relay 2 (COM) and 3 (NO) will close.

If the phase sequence is correct, the relay LED will light up; the terminals of relay 1 (NC) and 2 (COM) are disconnected and the contacts of relay 2 (COM) and 3 (NO) are closed. If the the phase sequence is incorrect, the relay LED will light up, the relay LED will turn off and the contacts of the relay no. 1 (NC) and 2 (COM) will close and the contacts of relay no. 2 (COM) and 3 (NO) will will disconnect.

If the voltage value exceeds the set high voltage value, the LED will light up high voltage error indicator LED (U>). If the voltage value does not drop below the normal value within 2 seconds, the device will have a high voltage error voltage. In this position, the relay LED will turn off, the contacts of relay no. 1 (NC) and 2 (COM) are closed and the contacts of relay no. 2 (COM) and 3 (NO) are open. When the voltage value drops below the set high voltage value by 5 V, the LED the high voltage error indicator LED will turn off and the device will start counting down the error delay time (t). After the waiting time for the error has elapsed, the LED will light up relay LED, the contacts of relay no. 1 (NC) and 2 (COM) are open and the contacts the contacts of relay no. 2 (COM) and 3 (NO) are closed.

If the voltage values drop below the set low voltage value, the LED will light up LED indicating low voltage error (U <). If the voltage values during the error delay time does not increase to the normal value, the device will have the low voltage error. In this position, the relay LED will turn off, the terminals of relay no. 1 (NC) and 2 (COM) are closed and the contacts of relay no. 2 (COM) and 3 (NO) are open. If the voltage value exceeds the set low voltage value by 5 V, the LED indicating low voltage error will turn off and the device will start count down the error delay time (t). After the error delay time has elapsed, the relay LED lights up and the contacts of relay no. 1 (NC) and 2 (COM) are open and the contacts of relay no. 2 (COM) and 3 (NO) are closed.

Main characteristics:

Operational voltage (Un): 3x380 VAC

Operational frequency: 50/60 Hz.

Operational power: <4 VA

Operational temperature: From -20 °C to 55 °C

Low voltage: 180 VAC (fixed)

High voltage: 500 VAC (fixed)

Asymmetry: ~% 11 (fixed)

Without neutral conductor: yes

Indication: 5 LEDs

Contact: Active load 5A / 250 VAC

Diameter cable: 2.5 mm2

Weight: <110 g.

Mounting: Mounting on DIN rail