3. A 415 V, 250 HP, six-pole, 50 Hz induction motor has a full load slip of 4%, an efficiency of 89 %, and a power factor of 0.89 lagging. At start up, the motor develops 175 % of FLT, but draws 7 times full load current (on rated voltage). The motor must develop at least FLT at switch on, to ensure successful starting. If the fault level at the 415 V switchboard is 15 MVA, calculate the maximum length of cable which may be used to connect the motor, if the cable has reactance 0.005 2/metre. The above motor is to be corrected to operate at 0.95 lagging power factor. Calculate the amount of capacitance required to be connected at the stator terminals of the machine to achieve this, and the resulting capacitor values. 4.5 m, 12.8 kVAr per phase, 0.7 mF

5. The term 'Locked rotor torque' applies When the induction motor speed is zero When the induction motor is at nominal speed When the induction motor synchronous speed When the induction motor speed is at breakdown torque

Please answer all subpart either dislike is ready Please all subpart in short please..

A) At what percentage of slip is the pull-out or breakdown torque of a typical 3-phase squirrel- cage induction motor reached? 21. a) 3% slip b) 10% slip c) 20% slip d) none of the above B) If load is increased beyond the breakdown torque, what happens to the speed of the motor? a) it stops b) it may speed up beyond its rated rpm c) its speed will not change, but its current will go down d) none of the above