The function of intermediate relay is to change one input signal to one or more output signals. Its input signal is energizing or deenergizing of coil. When the coil is energized, it will produce magnetic force to attract/close the contact. Its output is the acting of the contact to transmit the signals to the control signals or loop at the same time. 

The commonly used intermediate relay are two kinds of JZ7 series and JZ8 series, of which the structure of JZ7 series relay  is similar to the contactor. It is composed of core,  static iron core, dynamic iron core, contact system and the reaction spring. It has more contacts, generally speaking, there are 8 pairs of contacts, which can be composed of three forms: four pairs of normal open, four pairs of normal close; or six pairs of normal open, 2 pairs of normal close; or 8 pairs of normal open.