(Solved): A. A three-phase, 60-Hz induction motor runs at 890 r/min at no load and at 840 r/min at full load. ...

A. A three-phase, 60-Hz induction motor runs at 890 r/min at no load and at 840 r/min at full load. (a) How many poles does this motor have? (b) What is the slip at rated load? (c) What is the speed at one-quarter of the rated load? (d) What is the rotor's electrical frequency at one-quarter of the rated load? B. A 50-kW, 440-V, 50-Hz, six-pole induction motor has a slip of 6 percent when op- erating at full-load conditions. At full-load conditions, the friction and windage losses are 300 W, and the core losses are 600 W. Find the following values for full- load conditions: (a) The shaft speed n (b) The output power in watts (c) The load torque Toad in newton-meters (d) The induced torque Tind in newton-meters (e) The rotor frequency in hertz