Short-Circuit Overload Protection of Three-Phase Outgoing Feeder type OSC3

Overload protection of three-phase outgoing feeders type OSC3 is used to protect the motors against the effects of overload, short circuit and supply current phase imbalance.

The protection works with external current-voltage converters. It has a wide range of settings, depending on the converters used. It is also possible to use current transformers, because after shorting them with a low resistance it is possible to express the signal in [mV/A].

Communication with the user is via text messages displayed on the display. Buttons are provided to navigate the device menu.

The protection has LEDs indicating the operating status of the device. Remote access to the device is via the RS-485 interface using the Modbus RTU protocol. As standard the device is fitted with one digital input I0, which is intended as an external input for clearing messages appearing on the display (equivalent to the “RESET” button). The device may be optionally fitted with a larger number of general-purpose inputs whose logical status is indicated on the display and can be read remotely.


  • any transformer setting,
  • selection of overload characteristics class,
  • MODBUS communication as standard.

Explosion protection

Rated values

Ingress protection rating

Ambient temperature
-20°C to +70°C

Supply voltage
24 V DC/42 V AC

Rated current setting range
for 5 mV/A1 converter
0.5… 630 A

Rated current setting range
for 5 mV/A1 converter
1.0 … 1000

Rated current setting range
for 5 mV/A1 converter
2.5… 2500

Setting range for rated current
0.10 A ÷ 2 A with 0.01 A step
2.0 A ÷ 10 A with 0.05 A step
10 A ÷ 25 A with 0.1 A step
25 A ÷ 100 A with 0.5 A step
100 A ÷ 250 A with 1 A step
250 A ÷ 1000 A with 5 A step
1000 A ÷ 2500 A with 10 A step
(remotely freely with 0.01 A step)

Access password
combinations 00000000 ÷ 99999999

User interface language
Polish, English, German, Spanish, Czech, Russian, Turkish

Dimensions [mm]
90 x 65 x 110mm