The RR-OA3 is an overcurrent relay designed to monitor current in each phase of a 3 phase systems and provides a relay operation when an overcurrent condition occurs.

RR-OA3 can be used together with Earth Fault Relay Type RR-EF1 to protect the electric circuit from overcurrent and earth fault. and earth fault.

The RR-OA3 is housed in a DIN standard 96 x 96mm case which is of front panel mounting. This feature provides major economic and safety benefits, when compared with the traditional DIN rail mounted product. Any required re-adjustment or function checking, can be achieved without the need to access the live side of the panel.

The RR-OA3 also has the benefit over conventional current relay in that it indicates which phase current has reached the trip level (applicable only for independent auxiliary supply).

The relay has customer adjustable current input setting from 2 to 6 Amps for each phase and an adjustable time delay of 0 to 1 second. A manual push to "TEST" button is provided for checking the relay operation. To test the relay, push the “Test” button, L.E.D. of each phase and timer ( after setting time respectively) will be lighted. The status of the relay is always apparent from the front panel. A Red LED indicates the state of the relay, and a further 3 Red LED's are provided to indicate which phase current has exceeded the preset level. The state of the auxiliary power supply is indicated, via a Green LED.

The relay is latched so once an over current occurs, the relay remains energized, regardless of the condition of any of the individual 3 phase currents.

The relay can be reset via a reset button on the front of the RR-OA3 without breaking the locking seal. A transparent plastic lockable front cover is provided for sealing purposes to ensure that unauthorized personnel can not tamper with the set point or the time delay of the 3 phase over current relay.