3UA Series Overload Relays are suitable for overload and phase - failure protection of AC motors with frequency of 50/60Hz, voltage up to 690 ~ 1000V, current up to 0.1 ~ 400A under 8 - hours duty or uninterrupted duty. The relays are also suitable for overload protection of DC magnet and DC motors. The relays comply with IEC947-4, VDE0660 and GB14048. Several functions provided by these relays are: phase-failure protection, temperature compensation, ON/OFF indication and manual/automatic reset. The relays can be mounted onto contactors or installed as single units. Used for for  installing 3UA50 as a single unit.