JR20 series thermal relay is suitable for the power system of AC 50/60Hz, main circuit rated voltage up to 660V, current up to 630A, used as protecting AC three-phase motor against overload and phase losing, and forming electromagnetic with starter CJ20 series AC contactor. It has functions of phase-losing protection temperature compensation, trip indication. It can manually and automatically get back. The product conforms to GB14048.4, IEC60947-4 standard.