The Motor Power-Factor Relay is a protective relay that is sensitive to power factor. Because the phase angle between the motor current and voltage, and thus, the power factor, is dependent on the mechanical load applied to the motor, this relay can be used to detect either underload or overload conditions for a three-phase induction motor. Power factor setpoint and start delay adjustments, and an underload/overload selection switch are provided along with a single set of contacts. The adjustable start delay is a useful feature which prevents the relay from tripping while the motor is starting.