3a) How does efficiency of a synchronous machine vary when used as a generator and motor....
3a) How does efficiency of a synchronous machine vary when used as a generator and motor.
3b) What is the effect of adjusting field current and torque on a synchronous machine.
3c) Draw a space-time phasor diagram to show operation of a machine connected to large system (infinite bus) assuming the machine has a uniform air gap.
Homework Answers
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3a) How does efficiency of a synchronous machine vary when used
as a generator and motor....
a. The figure below is a set of Synchronous Generator and Synchronous Motor. The ratings of...
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...
3. (30) A simple power system, shown below, is made up of a synchronous generatcr connected to a synchronous motor through a couple of transformers and a transmission line. The reactances of the...
3. (30) A simple power system, shown below, is made up of a synchronous generatcr connected to a synchronous motor through a couple of transformers and a transmission line. The reactances of the different elements of the system are all given in pu as: Xsg-0.5 X of each transformer-10 % Xsm-0.5 X transmission line 0.3 The synchronous motor is connected to an infinite bus Hint: The great advantage of an infinite bus is that it always remains constant and our...
Question 4. (30 Marks) A 480V, Y-connected, 4-pole synchronous motor is drawing 40A at unity powe...
Question 4. (30 Marks) A 480V, Y-connected, 4-pole synchronous motor is drawing 40A at unity power factor from a 480V "infinite" bus. The field current flowing under these conditions is 4A. Its synchronous reactance is 8Ω (neglect Ra). Assume a linear open-circuit characteristic. a) Find the internal voltage and the torque angle for these conditions. b) Draw the Phasor diagram for this condition. On the same axis, use dashed lines to show the Phasor for 0.8 lagging operation while consuming...
b) A 1MW, 3300 V, 50 Hz, wye-connected, 3-ф, twenty four-pole, synchronous motor has a synchronous...
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...
Problem 1: Synchronous Machine Generator and Motor Operation A 10 MVA, 2300 Volt (Line to line...
Problem 1: Synchronous Machine Generator and Motor Operation A 10 MVA, 2300 Volt (Line to line xms) uniform airgap synchronous machine has a synchronous reactance of 0.9 pu at 60 Hz and resistance may be neglected. The machine is connected to a 2300 Volt constant voltage, constant frequency source and operated as described below (a) Generator Operation - Find the power, reactive power, current, and the required internal voltage E for generator operation at rated volt-amperes and power factors of...
A 3-phase, 100 MVA, 11 kV, 60 Hz, 200 rpm synchronous generator has synchronous reactance of...
A 3-phase, 100 MVA, 11 kV, 60 Hz, 200 rpm synchronous generator has synchronous reactance of 12 2 and negligible stator resistance. a. The generator is connected to an infinite bus and delivers 80 MW at 0.8 leading power factor. Determine the power angle and excitation voltage EA. Draw the phasor diagram. b. The field current of the generator is now slowly reduced until the generator reaches its static stability limit (5=0). For this condition, determine the power angle, excitation...
A 100MVA synchronous generator is connected to a 25kV infinite bus through two parallel transmission lines....
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...
Problem 2 (30%) Space Vectors and Phasors in an ABC sequenced and balanced synchronous machine (motor/generator), if the current going through phase A si 1414cos(120t +60)A 3.1) What is the phaso...
Problem 2 (30%) Space Vectors and Phasors in an ABC sequenced and balanced synchronous machine (motor/generator), if the current going through phase A si 1414cos(120t +60)A 3.1) What is the phasor for this current? What is the corresponding space vector for this current? 3.2) If the maximum air-gap flux density created by i, is 5000T, then, at an air-gap point that has angle 0 with respect to the a-axis of the stator, what is the air-gap flux density created by...
6) 480 V, 0.5 KHz. A -connected. P-pole synchronous generator. This generator has a synchronous reactance...
6) 480 V, 0.5 KHz. A -connected. P-pole synchronous generator. This generator has a synchronous reactance of 0.11 and an armature resistance of 0.015 N. IL = 1310- At full load, the machine supplies 1200 A at 0.8 PF lagging. The phasor diagram of the generator is shown below. E RU 1. = 692.82 -36.87°A Figure 2 i. 11. Calculate the number of poles (P) if the speed of rotation of this generator ise 3000 r/min? [2 marks] If the...
Search Results for: A 100 kVA, 1100 V, three-phase, 6-pole, Y-connected, 50 Hz synchronous machine has synchronous reactance of 6 $2 per-phase and negligible armature resistance. Its core losses are 7 kW and its friction and windage losses are 8 kW. The s
A 100 k VA, 1100 V, three-phase, 6-pole, Y-connected, 50 Hz synchronous machine has synchronousreactance of 6 92 per-phase and negligible armature resistance. Its core losses are 7 k W and itsfriction and windage losses are 8 kW. The speed droop is 2.5%.Initially the machine is operated alone as a generator and the field current is adjusted such that theno-load voltage equals the rated voltage.a) If the generator is supplying a line current of $2.5 A at 0.85 PF lagging....
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...
3. (30) A simple power system, shown below, is made up of a synchronous generatcr connected to a synchronous motor through a couple of transformers and a transmission line. The reactances of the different elements of the system are all given in pu as: Xsg-0.5 X of each transformer-10 % Xsm-0.5 X transmission line 0.3 The synchronous motor is connected to an infinite bus Hint: The great advantage of an infinite bus is that it always remains constant and our...
Question 4. (30 Marks) A 480V, Y-connected, 4-pole synchronous motor is drawing 40A at unity power factor from a 480V "infinite" bus. The field current flowing under these conditions is 4A. Its synchronous reactance is 8Ω (neglect Ra). Assume a linear open-circuit characteristic. a) Find the internal voltage and the torque angle for these conditions. b) Draw the Phasor diagram for this condition. On the same axis, use dashed lines to show the Phasor for 0.8 lagging operation while consuming...
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...
Problem 1: Synchronous Machine Generator and Motor Operation A 10 MVA, 2300 Volt (Line to line xms) uniform airgap synchronous machine has a synchronous reactance of 0.9 pu at 60 Hz and resistance may be neglected. The machine is connected to a 2300 Volt constant voltage, constant frequency source and operated as described below (a) Generator Operation - Find the power, reactive power, current, and the required internal voltage E for generator operation at rated volt-amperes and power factors of...
A 3-phase, 100 MVA, 11 kV, 60 Hz, 200 rpm synchronous generator has synchronous reactance of 12 2 and negligible stator resistance. a. The generator is connected to an infinite bus and delivers 80 MW at 0.8 leading power factor. Determine the power angle and excitation voltage EA. Draw the phasor diagram. b. The field current of the generator is now slowly reduced until the generator reaches its static stability limit (5=0). For this condition, determine the power angle, excitation...
Problem 2 (30%) Space Vectors and Phasors in an ABC sequenced and balanced synchronous machine (motor/generator), if the current going through phase A si 1414cos(120t +60)A 3.1) What is the phasor for this current? What is the corresponding space vector for this current? 3.2) If the maximum air-gap flux density created by i, is 5000T, then, at an air-gap point that has angle 0 with respect to the a-axis of the stator, what is the air-gap flux density created by...
6) 480 V, 0.5 KHz. A -connected. P-pole synchronous generator. This generator has a synchronous reactance of 0.11 and an armature resistance of 0.015 N. IL = 1310- At full load, the machine supplies 1200 A at 0.8 PF lagging. The phasor diagram of the generator is shown below. E RU 1. = 692.82 -36.87°A Figure 2 i. 11. Calculate the number of poles (P) if the speed of rotation of this generator ise 3000 r/min? [2 marks] If the...
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