Tutorial Problem No. 34.1 1. In the case of an 8-pole induction motor, the supply frequency was 50-Hz and the shaft speed was 735 rpm. What were the magnitudes of the following: (i) synchronous speed (iii) per unit slip, (ii) speed of slip (iv) percentage slip 3. An 8-pole alternator runs at 750. rp.m. and supplies power to a 6-pole induction motor which has at full-load a slip of 3%. Find the full-load speed of the induction motor and the frequency of its rotor e.m.f. 4. A 3-phase. 50-Hz induction motor with its rotor star-connected gives 500 V (r.m.s.) at standstill between the slip-rings on open-circuit. Calculate the current and power factor at standstill when the rotor winding is joined to a star-connected external circuit, each phase of which has a resistance of 10 12 and an inductance of 0.04 H. The resistance per phase of the rotor winding is 0.2.12 and its inductance is 0.04 H. Also, calculate the current and power factor when the slip-rings are short-circuited and the motor is running with a slip of 5 per cent. Assume the flux to remain constant.