A salient-pole synchronous generator with saturated Xd = 1.57 A salient-pole synchronous generator with saturated synchronous reactances Xd = 1.57 per unit and Xq = 1.34 per unit is connected to an infinite bus of rated voltage through an external impedance X bus = 0.11 per unit. The generator is supplying its rated MVA at […]
b. Calculate the no-load rotational loss. c. The motor is suppli b. Calculate the no-load rotational loss. c. The motor is supplied from a 30-V dc supply through a PWM inverter. Table gives the measured motor current as a function of the PWM duty cycle D. Complete the table by calculating the motor speed and […]
A dc-motor shunt field winding of resistance 210Ω is to be A dc-motor shunt field winding of resistance 210東 is to be supplied from a 220-V rms, 50-Hz, three-phase source through a three-phase, phase controlled rectifier. Calculate the delay angle 杰d which will result in a field current of 1.1 A.
At standstill the rms currents in the main and auxiliary At standstill the rms currents in the main and auxiliary windings of a four-pole, capacitor-start induction motor are/main = 20.7 A and Iaux = 11.1 A respectively. The auxiliary-winding current leads the main-winding current by 53째. The effective turns per pole (i.e., the number of […]
A shunt motor operating from a 230-V line draws a full-load A shunt motor operating from a 230-V line draws a full-load armature current of 46.5 A and runs at a speed of 1300 r/min at both no load and full load. The following data is available on this motor: Armature-circuit resistance (including brushes) = […]
A salient-pole synchronous generator with saturated Xd = 0.78 A salient-pole synchronous generator with saturated synchronous reactances Xd = 0.78 per unit and Xq = 0.63 per unit is connected to a rated-voltage infinite bus through an external impedance X bus = 0.09 per unit. a. Assuming the generator to be supplying only reactive power […]
A dc shunt motor operating at an armature terminal voltage A dc shunt motor operating at an armature terminal voltage of 125 V is observed to be operating at a speed of 1180 r/min. When the motor is operated unloaded at the same armature terminal voltage but with an additional resistance of 5 O in […]
A long, thin solenoid of radius r0 and height h A long, thin solenoid of radius r0 and height h is shown in figure. The magnetic field inside such a solenoid is axially directed, essentially uniform and equal to H = Ni/h. The magnetic field outside the solenoid can be shown to be negligible. Calculate […]
Consider a three-phase synchronous motor for which you are given Consider a three-phase synchronous motor for which you are given the following data: Rated line-to-line voltage (V), Rated volt-amperes (VA), Rated frequency (Hz) and speed (r/min), Synchronous reactance in per unit, Field current at rated open-circuit voltage (AFNL) (A). The motor is to be operated […]
Consider the 8-kV: 78-kV, 50-MVA transformer of Problem 2.15 con Consider the 8-kV: 78-kV, 50-MVA transformer of Problem 2.15 connected as an autotransformer. a. Determine the voltage ratings of the high- and low-voltage windings for this connection and the kVA rating of the autotransformer connection. b. Calculate the efficiency of the transformer in this connection […]