MFAC relays provide high-speed differential protection for various types of power system plants including generators, reactors, busbars, motors and the individual windings of power transformers.

Providing high-speed differential protection, the MFAC relay is fast and reliable due to its simple electromechanical construction. It operates as a high impedance unit protection scheme and has a wide range of settings. 

Two versions for phase and earth fault protection
The MFAC relay operates as a high impedance unit protection scheme, with settings determined by a series of resistors. The resistors are selected on a seven-way plug bridge.

MFAC 14, a single element version, is applied only when earth fault protection is required. MFAC 34, comprised of three elements, provides both phase and earth fault protection.

Wide settings range with a simple, robust design
Ensuring high stability with through faults, MFAC relays benefit from a simple application technique. With 'tuned to rated frequency' and a wide settings range, the MFAC has a robust and straightforward design.