26. A d.c. series motor, having armature and field resistances of 0-06 n and 0-04 n respectively, was tested by driving it at 2000 rev/min and measuring the open-circuit voltage across the armature terminals, the field being supplied from a separate source. One ofthe readings taken was: field current, 350 A; armature p.d., 1560 V. From the above information, obtain a point on the speed/current-characteristic, and one on the torque/current characteristic for normaloperation at 750 V and at 350 A. Take the torque due to rotational loss as 50 N-m. Assume that brush drop and field weakening due to armature reaction can be neglected. (S.A.N.C., 0.2)