Voltage-based phase-loss relays have very limited reliability for motor protection. They should only be relied upon to inhibit motor starting, in what US typically calls "3-wire control" obliging {investigation before} manual restart. Current-balance protection is more reliable, but usually must be inhibited for the interval during starting.
Careful review of claimed protection capabilities is warranted.
Compared to NEMA T-frame motors, sensitivity to and damage from voltage imbalance is typically much greater for hermetic-refrigeration compressors and submersible water pumps, given their usual high current densities and low thermal inertia from compact {induction-motor stator} design.
