A 250-volt series motor having armature and series field resistances of 0.2 N and 0.05 2 respectively, draws 50 amperes when running at a speed of 850 revs per minute. Determine: The mechanical output power and efficiency under these conditions, if the core, and mechanical losses amount to 1.125 kW. The e.m.f. and the developed power. (Note: The developed power is the power developed in the armature, before the iron and mechanical losses are subtracted) The developed torque. 4 If the mechanical load is now increased by 15%, causing the load current to increase to 65 amperes, determine: 1 The new input power and output power. 2 The new speed. 3 The new developed torque.