MRR1A Rotor Earth Fault Relayt 19" Rack

The generator rotor protection relay MRR1 com-bines rotor earth fault protection, excitation overand undercurrent protection as well as rotating diode failure protection. Thus providing a powerful protection regarding the rotor of synchronous generators, covering the following ANSI codes:

37 DC undercurrent relay

40 Field relay

58 Rectification failure relay

64 Ground detector relay

76 DC over current relay

The MRR1 is recommended for synchronous generators and motors above 1 MVA rating. The rotor earth fault element detects high and low resistance earth faults of the rotor winding.

It is equipped with two stages, one for alarm, one for trip. The excitation current protection element supervises the DC excitation current of brushless excitor machines.

The protective functions are: Undercurrent, overcurrent and ripple detection for diode failure protection.