Abstract: An electromagnet for use in an extremely inverse time overcurrent relay, wherein extremely inverse relay performance is obtained as a result of the electromagnet's simplified design. The electromagnet comprises a core having two E shaped portions of unequal size, each portion including a base wall, two outer legs and an inner leg, with the inner legs of the two portions being arranged in aligned opposition. The opposed and aligned inner legs of the core constitute magnetic pole members having opposed faces spaced apart and defining an air gap therebetween. Each pole member is provided with a shading ring shading the pole member by greater than 50%. Further, the electromagnet is provided with a single energizing means located on the core for establishing a flux distribution in the air gap whereby a rotatable armature which may be located in the air gap may be driven in response to an energizing current.