Describe the effect on the torque-speed characteristic of an ind Describe the effect on the torque-speed characteristic of an induction motor produced by (a) Halving the applied voltage and (b) Halving both the applied voltage and the frequency. Sketch the resultant torque-speed curves relative to that of rated-voltage and rated-frequency. Neglect the effects of stator […]
Read More »The dc motor of Problem 11.1 has a field-winding inductance The dc motor of Problem 11.1 has a field-winding inductance Lf = 3.7 H and a moment of inertia J = 0.081 kg 路 m2. The motor is operating at rated terminal voltage and an initial speed of 1300 r/min. a. Calculate the initial field […]
Read More »The following data apply to a 125-kW, 2300-V, three-phase The following data apply to a 125-kW, 2300-V, three-phase, four pole, 60-Hz squirrel-cage induction motor: Stator-resistance between phase terminals = 2.23 O. No-load test at rated frequency and voltage: Line current = 7.7 A Three-phase power = 2870 W. Blocked-rotor test at 15 Hz: Line voltage […]
Read More »The data sheet for a small permanent-magnet dc motor provides The data sheet for a small permanent-magnet dc motor provides the following parameters” Rated voltage: Vrated = 3 V, Rated output power: Prated = 0.28 W, No-load speed: nnl = 12,400 r/min, Torque constant: Km = 0.218 mV/(r/min), Stall torque: Tstall = 0.094 oz 路 […]
Read More »The dc motor of Problem 7.25 will be used to The dc motor of Problem 7.25 will be used to drive a load which requires a power of 0.75 W at a speed of 8750 r/min. Calculate the armature voltage which must be applied to achieve this operating condition. Is this the question you were […]
Read More »The armature of a two-pole dc generator has a total of 320 The armature of a two-pole dc generator has a total of 320 series turns. When operated at a speed of 1800r/min, the open-circuit generated voltage is 240 V. Calculate Фp, the air-gap flux per pole. Is this the question you were looking for? […]
Read More »The dc machine of Problem 7.4 is to be operated The dc machine of Problem 7.4 is to be operated as a motor supplied by a constant armature terminal voltage of 250 V. If saturation effects are ignored, the magnetization curve of Figure becomes a straight line with a constant slope of 150 volts per […]
Read More »The dc generator of Problem 7.4 is to be operated at a The dc generator of Problem 7.4 is to be operated at a constant speed of 1200 r/min into a load resistance of 2.5O. a. Using the “spline ( )” function of MATLAB and the points of the magnetization curve of Figure at 0, […]
Read More »An electromechanical system in which electric energy storage An electromechanical system in which electric energy storage is in electric fields can be analyzed by techniques directly analogous to those derived in this chapter for magnetic field systems. Consider such a system in which it is possible to separate the loss mechanism mathematically from those of […]
Read More »a. Calculate the no-load speed and rotational loss. b. Assuming a. Calculate the no-load speed and rotational loss. b. Assuming the rotational loss to be constant, use MATLAB to plot the motor output power as a function of speed. Limit your plot to a maximum power output of 15 kW. c. Armature-voltage control is to […]
Read More »
WebMail