• black icon of a bullhorn 30 years industry experience
  • black icon of three cubes Over 8,000 products in stock
  • Black icon of a clock Order by 16:00 and receive the next working day


3 phase over/under voltage relay H3US, H3USN

  • Phase control of line voltage
  • Wide range input voltage
  • 35 mm cabinet with DIN rail
  • LED indication

Product description

Control relay for monitoring of 3-phase networks with neutral (H3USN) and without neutral (H3US). Adjustable switch at the front for adjustment of correct voltage in 3-phase networks. The switch's position is not registered until the operating voltage is switched on. If the switch position is changed during operation, all LEDs (LED indications) begin to flash but the unit will continue to function normally with the voltage that was set at the most recent power connection. Monitors under-voltage between the phases that can be set between -2 % and -20 % of Un (measurement voltage) and over-voltage that can be set between 2 % and 20 % of Un. Each limit (over-/under-voltage) has its own relay output (R1 Over and R2 Under) and there is an adjustable time delay for each relay output (Tt1 and Tt2), adjustable between 0.3-30 s. H3USN also checks for neutral interruption. Green LED (Un) indicates supply voltage OK. Yellow LED (R) indicates active relay output.


Part numbers

Parts Price Selection of rated voltage Supply voltage
220, 380, 400, 415, 440, 480V 3 x 220-480V AC
120, 127, 220, 230, 240, 260, 277V 3 x 120-277V AC


Crouzet 3-phase voltage monitoring relay

Voltage Monitor Relay H3US 3 x 220-480V

Technical data

Approvals CE, CSA, RoHS, UL
Breaking capacity 5A, 250V AC/DC
Function Under/Overvoltage
IP class connection IP20
IP class housing IP30
Lower limit -2 - -20%
Mounting 35 mm DIN-Rail
Output 2x Relay
Selection of rated voltage 220, 380, 400, 415, 440, 480V
Storage temperature max 70 °C
Storage temperature min -40 °C
Supply voltage 3 x 220-480V AC
Temperature operational max 50 °C
Temperature operational min -20 °C
Time delay startup 0,5 s
Time delay when exceeding the limit value 0,3-30s
Upper limit 2 - 20%
Weight 130 g

Measurements and connections

Technical illustrations

  • Fast-blow fuse 100 A recommended on phase L1 before the relay

    Fast-blow fuse 100 A recommended on phase L1 before the relay

  • Over/under voltage<br />1: Over-voltage<br />2: Hysteresis<br />3: Under-voltage<br />4: L1, L2, L3<br />5: Relay R1<br />6: Relay R2<br />7: Delay at over-voltage limit value<br />8: Delay at under-voltage limit value

    Over/under voltage
    1: Over-voltage
    2: Hysteresis
    3: Under-voltage
    4: L1, L2, L3
    5: Relay R1
    6: Relay R2
    7: Delay at over-voltage limit value
    8: Delay at under-voltage limit value

Contact us

If you need any help, you can contact us in one of the following ways:

0116 284 9900

Send an e-mail

Use live chat