Homework Answers
Question 2
Voltage of an AC generator is controlled by increasing or
decreasing the field current.
Hence first choice is correct.
Question 3
The relation between frequency and speed is
N=(120f/p)
Where N is speed in rpm
f is frequency
P is number of poles.
Hence f=(NP/120)
Calculating f=60 hz
Hence first choice is correct.
Question 4
From previous question calculating f=40 hz.
Hence first choice is correct.
Question 5
Brushes and slip rings are used
Hence first choice is correct
Question 6
A field coil .
First choice is correct.
Question 7
The armature coil is fixed on the stator.
Question 8
Now from N=(120f/P)
Calculating N=3000 rpm
Question 9
Field.
Question 10
Again from formula
f = (NP/120)
Calculating f=50 Hz
Question 11
Armature coil is fixed on the rotor
Question 12
Armature
Question 13
50 Hz
Question 14
1.732 times greater than the phase voltage
Question 15
N=(120f/P)
P=120f/N
Calculating P=30 hence
15 pole pairs will be there .
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QUESTION 2 The voltage of an AC generator is controlled by? Increasing or decreasing the field...
Problem 1: A four pole, 60Hz, 3-d synchronous generator has a rotor radius of 15 cm, a rotor length of 2.7m, and an air gap length of 2 mm. The rotor field winding consists of 1000 turns with a wi...
Problem 1: A four pole, 60Hz, 3-d synchronous generator has a rotor radius of 15 cm, a rotor length of 2.7m, and an air gap length of 2 mm. The rotor field winding consists of 1000 turns with a winding factor of 0.962. The Δ connected armature winding has 25 series turns per phase with a winding factor of 0.935. The generator is designed to achieve rated open-circuit voltage at a peak air-gap flux density of 1.25 T (a) At...
QUESTION 8 When connecting any electrical AC generator to an electrical grid, the frequency, phase, and...
QUESTION 8 When connecting any electrical AC generator to an electrical grid, the frequency, phase, and voltage of the generator's final electrical output must match that of the grid. ○True ○ False QUESTION 9 As discussed in class, Inverters convert AC power to DC and Rectifiers convert DC to AC. Both are used in fully-rated power electronics in wind turbines to convert power from the stator and DC generator to the correct voltage and phase of the grid. O True...
44. The direction of rotation of an induction motor depends on a. the frequency of the...
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...
1) The armature of an ac generator is a rectangular coil 2.00 cm by 6.00 cm...
1) The armature of an ac generator is a rectangular coil 2.00 cm by 6.00 cm with 80 turns. It is immersed in a uniform magnetic field of magnitude 0.250 T. If the amplitude of the emf in the coil is 22.0 V, at what angular speed is the armature rotating? _______rad/s 2) The magnetic field between the poles of an electromagnet is 3.30 T. A coil of wire is placed in this region so that the field is parallel...
where the values of R1=0.25, Pin=441W ,Pcore-loss=37W, LR-voltage=45Vrms ,LR-current=28 Arms ,synchronus or nominal speed =12000, Actually...
where the values of R1=0.25, Pin=441W ,Pcore-loss=37W,
LR-voltage=45Vrms ,LR-current=28 Arms ,synchronus or nominal speed
=12000,
Actually that's what given in the question nothing else without
the recatance values ,
2. A three-phase induction machine is designed to operate at a near constant speed for the compressor of an environmental control system of an aircraft. The power system to which it is connected is a standard 400Hz, 115 Vrms (phase voltage) sinusoidal AC supply. The nominal speed for the compressor is...
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...
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...
2S QUESTION 3 (a) In the direct-current (d.c.) generator shown in Figure 03.1, (i) ?, is...
2S QUESTION 3 (a) In the direct-current (d.c.) generator shown in Figure 03.1, (i) ?, is the useful flux per pole, (ii)"N,' is the speed of the armature in revolutions per minute (rpm), (ii) 'p' is the number of pole-pairs/pairs of poles, (iv) 'Z' is the total number of conductors on the armature and (v) c' is the number of parallel paths through the winding between the positive and the negative brushes. From first principles and in not less than...
POR2-QUESTIONS FOR GENERATORS Answer True or False for the following. (Mechancal inbo Eleetvical) 1) Generators Convert...
POR2-QUESTIONS FOR GENERATORS Answer True or False for the following. (Mechancal inbo Eleetvical) 1) Generators Convert Thermal energy into Electrical energy. x 2) Increasing the speed of rotation of the magnet increases the rate of change of flux and higher voltage is induced. The same increase in voltage may be accomplished with out changing the speed, but by using a strong magnet. 3) The order or sequence in which the voltage waves of the three phases reach their max positive...
Q1 Consider a 24 slot machine. This machine is designed to have 4-poles a) If the...
Q1 Consider a 24 slot machine. This machine is designed to have 4-poles a) If the phase winding 5/6 pitched, draw winding diagram of phase A. b) What is the mechanical angle between the poles of a phase? c) What is the electrical angle between the poles of a phase? d) Calculate the number of coils per phase. e) Each coil has 10 turns. What is the number of turns per phase? f) The phase A current is 5 A....
Could you please help solve this question. The following generator supplying rated load into a large...
Could you please help solve this question.
The following generator supplying rated load into a large grid at rated voltage (11kV) and 0.85 PF lagging Generator: 20 MVA, X = j15%. Voltage 11kV i) Determine the internal generator voltage. ii) The load suddenly drops to 50% rated power. If the rotating energy of the generator and its associated turbine is 2.0 p.u-seconds when running at its synchronous speed. It has 2 poles and system frequency is 50 Hz. Determine: (ii-a)...
Problem 1: A four pole, 60Hz, 3-d synchronous generator has a rotor radius of 15 cm, a rotor length of 2.7m, and an air gap length of 2 mm. The rotor field winding consists of 1000 turns with a winding factor of 0.962. The Δ connected armature winding has 25 series turns per phase with a winding factor of 0.935. The generator is designed to achieve rated open-circuit voltage at a peak air-gap flux density of 1.25 T (a) At...
QUESTION 8 When connecting any electrical AC generator to an electrical grid, the frequency, phase, and voltage of the generator's final electrical output must match that of the grid. ○True ○ False QUESTION 9 As discussed in class, Inverters convert AC power to DC and Rectifiers convert DC to AC. Both are used in fully-rated power electronics in wind turbines to convert power from the stator and DC generator to the correct voltage and phase of the grid. O True...
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...
where the values of R1=0.25, Pin=441W ,Pcore-loss=37W,
LR-voltage=45Vrms ,LR-current=28 Arms ,synchronus or nominal speed
=12000,
Actually that's what given in the question nothing else without
the recatance values ,
2. A three-phase induction machine is designed to operate at a near constant speed for the compressor of an environmental control system of an aircraft. The power system to which it is connected is a standard 400Hz, 115 Vrms (phase voltage) sinusoidal AC supply. The nominal speed for the compressor is...
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...
2S QUESTION 3 (a) In the direct-current (d.c.) generator shown in Figure 03.1, (i) ?, is the useful flux per pole, (ii)"N,' is the speed of the armature in revolutions per minute (rpm), (ii) 'p' is the number of pole-pairs/pairs of poles, (iv) 'Z' is the total number of conductors on the armature and (v) c' is the number of parallel paths through the winding between the positive and the negative brushes. From first principles and in not less than...
POR2-QUESTIONS FOR GENERATORS Answer True or False for the following. (Mechancal inbo Eleetvical) 1) Generators Convert Thermal energy into Electrical energy. x 2) Increasing the speed of rotation of the magnet increases the rate of change of flux and higher voltage is induced. The same increase in voltage may be accomplished with out changing the speed, but by using a strong magnet. 3) The order or sequence in which the voltage waves of the three phases reach their max positive...
Could you please help solve this question.
The following generator supplying rated load into a large grid at rated voltage (11kV) and 0.85 PF lagging Generator: 20 MVA, X = j15%. Voltage 11kV i) Determine the internal generator voltage. ii) The load suddenly drops to 50% rated power. If the rotating energy of the generator and its associated turbine is 2.0 p.u-seconds when running at its synchronous speed. It has 2 poles and system frequency is 50 Hz. Determine: (ii-a)...
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