Protection Engineering Basics and Schemes Protection Engineering | Page 281

unbalance system if the difference between maximum
and minimum phases current is 100% our monitored
negative sequence current will be 100/1.732=57.8%.
9.8 Differential Protection
Motor with rating more than 1.5MW is need to be
protected from differential current faults means this
rating motor need differential protection relay.
9.9 Stalling of Motor
When motor fails to start or stall while running and
power supply still connected, then it will draw current
equal to locked rotor current(600 to 700% of full load
pg. 281