The combined multifunction motor protectionrelay is a secondary relay device which is connected to the current transformers of the protected motor drive. The three phase currentsand the neutral current of the protected deviceare continuously measured and on the basis ofthis measurement, the thermal condition of themotor is calculated and the faults of the networkare detected. In fault situations the protectiveunits of the relay provide alarm or trip thecircuit-breaker.By appropriate programming of the output relay matrix, various starting, prior alarm or restart inhibit signals are received as contactfunctions. This contact information is used e.g.for the blocking of co-operating protective relays located upstreams, for connection to annunciator units etc.The motor protection relay contains one external logic control input, which is activated by acontrol signal on the auxiliary voltage level. Theinfluence of the control input on the relay isdetermined by programming switches of themeasuring module. The control input can beused either for blocking one or more of theprotective stages, for carrying out an externaltrip order, for inhibiting a restart attempt or forresetting a latched output relay in the manualreset mode.