Solutions   for   Protecting   andManaging   the   Electrical   Network

PTG   7111 / 7113

Overpower or underpower relay

The PTG relays provide a simple and efficient soultion for problems involving the checking and controlling of power flow in balanced networks.

Two models are available:

  • The PTG 7111 is an overpower relay whose ranges of operating settings have been specifically chosen for the protection of diesel driven alternators against motoring conditions. These same ranges make it suitable for protectiong synchronous motors againt operation as generator. For these situations, it operates as a reverse power relays.
  • The PTG 7113 is an underpower relay whose principal application is its use in conjunction with the automatic starting and stopping of alternators operating in parallel. It may also be used to detect the un-priming of a pump, and to stop the driving motor.


  • PTG 7111: Overpower [32]
  • PTG 7113: Underpower [37]


  • Nominal current: 1 or 5 A (50 or 60 Hz)
  • Nominal voltage:
    with phase/phase VTs: 100, 110, 57.7 or 63.6 V
    without TVs: network 380/220 or 220/127 V
  • Setting ranges:
    PTG 7111: 5÷15%, 10÷30% or 40÷120%
    PTG 7113: 20÷60% or 40÷120%
  • Time delays: from 0.6 to 2.4 sec (see curve)
  • 2 NO or 1 NO+1 NC output contacts
  • n.1 hand reset mechanical opearation indicator


  Device Doc Type Lang. Ref. Index
PTG 7000 Leaflet EN / FR -- --
PTG 7111
PTG 7113
User Manual EN MI.1795 C
PTG 7111
PTG 7113
User Manual IT MI.1725 C
PTG 7111 Connection/Definition Diagram EN / FR 9696 C
PTG 7113 Connection/Definition Diagram EN / FR 9697 C