TR2 series of thermal overload relay can be  used in the circuit  of 50/60 HZ, rated insulation voltage 660 V, rated current 0.1-93A  for protecting the phase break when the electric motor is overload , the relay has different mechanism and temperature compensation can be pluged in ST1 series AC contactor,It is the most advanced thermal relay in the nineties in the world the products comply with IEC