The MS2P49 output relay is normally energised and drops out when phase angle unbalance is greater than the pre-set, under voltage or reverse phase sequence.
The main earth fault protection relays in distributions systems, power stations & large manufacturing / processing plants can fail to detect a high impedance breakdown to earth causing hazard to human life & potential damage to plant & equipment. In these & other situations demanding extra sensitive earth fault protection, the MS2P49 relay using solid state techniques, can be applied to detect earth currents down to 0.5% of the CT nominal current.
The MS2P49 relay is a phase failure relay suitable for 3 phase supplies. The relay is designed to provide protection for rotating equipment from the damaging effects of excessive negative sequence voltage resulting from phase failure, phase unbalance and reversed phase sequence. The MS2P49 output relay is normally energized and drops out when phase angle unbalance is greater than the pre-set, under voltage or reverse phase sequence. The MS2P49 may also be applied in automatic voltage changeover schemes in preference to the MS2P48 model where a neutral connection is not available or to reduce cost.