24. Synchronous motor delivers reactive power when: a. The terminal voltage leads the induced voltage in...
2.3 (20 points) A separately-excited de motor is mechanically coupled to a three-phase, 4-pole, 30-kVA, 460-V, round-rotor synchronous generator. The de motor is connected to a constant 230-V de supply The ac generator is connected to a 460 V, fixed-voltage, fixed-frequency, three-phase supply. The synchronous reactance of the synchronous generator is 513 Ω/phase. The armature resistance of the de motor is 30 m2. The 4-pole de machine is rated 30 kW at 230 V. All unspecified losses are to be...
QUESTION 19 A torque angle greater than 90°: A Indicates that the synchronous motor is now acting as a generator B. Is not possible in a synchronous machine C. Indicates that the synchronous motor is now acting as a synchronous condensor D. None of the other choices are correct E. Indicates that the direction of rotation of the motor is reversed QUESTION 20 Which of the following statements is true about busses? O A None of the other choices are...
A synchronous generator is driven by a diesel engine to provide electricity to a remote mining operation. The generator is three-phase, Y-connected, 60 Hz, 900 rpm, 600 V, 3300 kW, 4125 kVA, and it has a synchronous reactance of 0.120 Ω per phase. Ignore all losses, and assume the machine iron is not saturated.(a) The generator is set to deliver its rated active power at unity power factorand rated terminal voltage. Determine:i. The speed of the diesel engine driving the generator;ii. The rotor electrical...
The starting torque of a three-phase synchronous motor is increased when SE O ou h atic tio co e rotor electromagnet is turned on. a. b. the rotor electromagnet is turned off. c, the power factor of the ac power network is unity. d. dc power is applied to one of the stator windings. 2. When a synchronous motor without load is connected to a three-phase ac power network, the resulting power factor depends on a. the speed of the...
A 3-phase round rotor synchronous motor has a per phase terminal voltage of 480 V. This machine has a synchronous resistance and reactance of 0.25 ohm and 3.8 ohms, respectively. The excitation and field voltage of this machine is equal to 457 V and 150 V, respectively. The machine is operating at a torque angle of -8° and its field current equal to 3 A. With total rotational losses equal to 700 W, determine the following: a. Input Real and...
Question 5 (Svnchronous machines) a. A synchronous generator connected to an infinite grid has its frequency and terminal b. A six-pole, Y-connected three-phase synchronous machine rated 208 V (line-to- voltage fixed. What is the effect of increasing the excitation current in this case? line), 5500 VA has a synchronous reactance of 8 2 per phase at rated terminal voltage. It is operating as a generator connected to an infinite grid Determine the excitation voltage and the power angle if the...
b) A 1MW, 3300 V, 50 Hz, wye-connected, 3-ф, twenty four-pole, synchronous motor has a synchronous reactance of 3.24 2 per phase. Assume armature resistance is negligible. This machine is connected to an infinite bus-bars at 3300 V. Its field excitation is adjusted to provide P.F-1 at rated load Calculate: 0 the internal generated voltage EA and armature current la at rated conditions (S marks) ii) the maximum power and torqu e that the motor can deliver with its Ir...
A 100MVA synchronous generator is connected to a 25kV infinite bus through two parallel transmission lines. The synchronous reactance of the generator is 2.5Ω. Each transmission line has inductive reactance of 2Ω and 0.2Ω resistance. The generator delivers 90MVA to the infinite bus at 0.8 power factor lagging. For the above conditions, calculate: a. The terminal voltage of the generator b. The equivalent field voltage and power angle c. The real power output at the generator terminals d. The reactive...
a. The figure below is a set of Synchronous Generator and Synchronous Motor. The ratings of the machines are as follows: Synchronous Generator:. 3ph, 1.0MVA, 2.3kV, 50Hz, 0.85 lagging power factor, X.=0.9 pu Synchronous Motor: 3ph, 0.5 MVA, 2.36V, 50Hz, 0.85 leading power factor, X.=0.8 pu Synchronous generator Synchronous motor The generator is equipped with a voltage regulator which maintains the terminal voltage at the rated value. The motor delivers 500 hp and it field current is adjusted to make...
44. The direction of rotation of an induction motor depends on a. the frequency of the input voltage b. the strength of the magnetic field set up c. the phase sequence of the input supply lines and order in which they are connected to the stator windings d. whether the windings are connected in delta or star determines the speed of the rotating magnetic field a. the number of poles in the motor b. the frequency of the supply d...