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IL 9079

Short-time Voltage Drop Relay

IL 9079


Nominal voltage

Reset value

Operate delay

Approvals and Markings


  • 0047561
  • IL9079.12 3AC230/400V 0,8UN 0,2-2S
Monitoring of voltage systems to detect auto reclosing as e.g. generated by the energy supplier... more

Product description

Monitoring of voltage systems to detect auto reclosing as e.g. generated by the energy supplier in the case of flash-overs or switching procedures. It is possible that in control circuits some of the devices are resetted during auto reclosing and some not. Because of this uncontrollable situations may occur. By detecting these fast auto reclosings and addition of a certain time delay at reclosing the OFF-time is lengthened and every device has the time to reset. The circuit goes into a defined OFF state and is automatically resetted after the adjusted time delay or by manual reset if the automatic reset is disabled by an external circuit.

Technical specifications

Width: 35 mm
Operate delay: Yes
1- / 3-phase: 1, 3
Nominal voltage max.: 3/N AC 400 / 230 V
Auxiliary voltage: Without
Output contacts: 2 C/O contacts
Enclosure design: Distribution board
Type: IL 9079


  • According to IEC/EN 60255-1
  • Fast detection of undervoltage or phase failure in three-phase voltage systems
  • Detects auto reclosing of 20 ms
  • Adjustable response value 0.55 ... 1.05 UN
  • Operate delay to generate a defined reset signal
  • Manual reset possible with external circuit
  • Single-phase connection possible
  • Optionally fixed response value 0.8 UN
  • De-energized on trip
  • Green LED indicate for closed contact
  • Independant of phase sequence
  • 3p4w connection
  • Optionally for 3p3w systems
  • 2 changeover contacts
  • Devices available in 2 enclosure versions:
    IL 9079: Depth 59 mm, with terminals at the bottom for installation systems and industrial distribution systems according to DIN 43880
    SL 9079: Depth 98 mm, with terminals at the top for cabinets for mounting plate and cable duct
  • Width 35 mm