Homework Answers
Presently, the large synchronous machines are using brush less excitation system. It is because it requires less maintenance due to the absence of brushes and slip rings. The power loss is also reduced . A Brushless Exciter is a small direct coupled AC generator with its field circuit on the stator and the armature circuit on the rotor. The three phase output of the AC exciter generator is rectified by solid state rectifiers. The rectified output is connected directly to the field winding, thus eliminating the use of brushes and slip rings.
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Considering the plot of open circuit voltage vs. speed, is the machine excited using brushes or a...
Synchronous Machines Considering the plot of open circuit voltage vs. speed, is the machine excited using...
Synchronous Machines
Considering the plot of open circuit voltage vs. speed, is the machine excited using brushes or a brushless exciter? Explain your choice 1. Open Circuit Speed Test 200 150 2 100 50 1500 Speed (rpm
A 250V, 50A separately excited DC motor has armature resistance of 0.8 ohms (including brushes) and...
A 250V, 50A separately excited DC motor has armature resistance of 0.8 ohms (including brushes) and field resistance of 100 ohms. Kf for this motor is 1.5 V/(A.rad/sec). The armature circuit can carry up to 50A for a short time period. It is desired to run it with a 250 V voltage source in no load conditions with the speed of 1500 r/min. a) Explain the required equipment and steps. b) Draw the circuit for steady-state operation with the speed...
The following readings were taken during an open-circuit test and short-circuit test on a three-phase, 10...
The following readings were taken during an open-circuit test and short-circuit test on a three-phase, 10 MVA, 13.8 kV, 50 Hz synchronous generator driven at rated speed. Open Circuit Test Field Current 150 A 180 A 200 A 250 A 300 A 350 A Line voltage 11.2 kV 12.0 kV 12.5 kV 13.5 kV 14.3 kV 14.8 kV Short Circuit Test Field Current 150 A 180 A Short Circuit Current 400 A 480 A a) Plot the open-circuit and short-circuit...
Results and Discussion: 1. Plot machine speed vs resistance
DC series MOTOR...
LABResults and Discussion: 1. Plot machine speed vs resistance 2. Plot machine speed vs current 3. Explain the above plots 4. Using DC Motor Theory, explain the current profile you obtained 5. Plot the motor speed against the input voltage. Explain the results obtained. 6. Using the graph, right, determine the torque at each current setting. Plot the motor speed (n) against the torque (T) of the motor. Discuss the results obtained. 7. Calculate the efficiency of the motor at each current setting. Plot...
DC series MOTOR... LAB I need help answering question 6 and 7. Results and Discussion: 1. Plot machine speed vs resistance 2. Plot machine speed vs current 3. Explain the above plots 4. Using DC M...
DC series MOTOR...
LAB
I need help answering question 6 and 7.
Results and Discussion: 1. Plot machine speed vs resistance 2. Plot machine speed vs current 3. Explain the above plots 4. Using DC Motor Theory, explain the current profile Totque (mV) 12 you obtained Plot the motor speed against the input voltage. Explain the results obtained. Using the graph, right, determine the torque at each current setting. Plot the motor speed (n) against the torque (T) of the...
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...
Open/short circuit of star connected motor question help
Question: The equivalent circuit parameters of a 440 V, 3-phase, 8-poles, and 50 Hz star connected motor are given below. The short-circuit test is conducted with a locked rotor and a line current of 80 A. The open-circuit test is conducted by supplying the stator winding at rated voltage and at the same time driving the rotor in the same direction as the rotating field, at synchronous speed; s=0.R1 = 0.1, X1 = 0.5, RI2 = 0.1, XI2 = 0.5,...
A signal source with an open-circuit voltage of Vs = 2 mV rms and an internal...
A signal source with an open-circuit voltage of Vs = 2 mV rms and an internal resistance of 50 kΩ is connected to the input terminals of an amplifier having an open-circuit voltage gain of 100, an input resistance of 135 kΩ , and an output resistance of 4 Ω. A 4 Ω load is connected to the output terminals. Find Voltage gain Avs = V0/Vs Find voltage gain Av = V0/Vi Find current gain Ai Find power gain G...
1. (25 points) The following data are obtained from a 3-phase, 10MVA, 14kV, Y-connected synchronous machine....
1. (25 points) The following data are obtained from a 3-phase, 10MVA, 14kV, Y-connected synchronous machine. Field Current (A)Open-Circuit Voltage Short-Circuit Current line-to-line 8.0 12.0 16.0 19.2 21.6 250 375 500 625 750 100 150 200 250 300 In the DC test, a voltage of 50V is applied and the current is found to be 25A. Find the per-phase unsaturated synchronous reactance and armature resistance for the machine
3c) Induction Machine Analysis [ 8 marks ] A 415 V, 50 Hz, 1450 rpm, three-phase,...
3c) Induction Machine Analysis [ 8 marks ] A 415 V, 50 Hz, 1450 rpm, three-phase, star-connected induction machine has the following equivalent circuit parameters (referred to the stator winding where appropriate) stator resistance R 0.3 ohms, rotor resistance R2 0.2 ohms stator leakage reactance X 2 ohms, rotor leakage reactance X2' 2 ohms magnetising reactance XM 50 ohms, core loss resistance Rc 200 ohms In your calculations, you should use = the simplified equivalent circuit i) Find the number...
Synchronous Machines
Considering the plot of open circuit voltage vs. speed, is the machine excited using brushes or a brushless exciter? Explain your choice 1. Open Circuit Speed Test 200 150 2 100 50 1500 Speed (rpm
DC series MOTOR...
LAB
I need help answering question 6 and 7.
Results and Discussion: 1. Plot machine speed vs resistance 2. Plot machine speed vs current 3. Explain the above plots 4. Using DC Motor Theory, explain the current profile Totque (mV) 12 you obtained Plot the motor speed against the input voltage. Explain the results obtained. Using the graph, right, determine the torque at each current setting. Plot the motor speed (n) against the torque (T) of the...
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...
1. (25 points) The following data are obtained from a 3-phase, 10MVA, 14kV, Y-connected synchronous machine. Field Current (A)Open-Circuit Voltage Short-Circuit Current line-to-line 8.0 12.0 16.0 19.2 21.6 250 375 500 625 750 100 150 200 250 300 In the DC test, a voltage of 50V is applied and the current is found to be 25A. Find the per-phase unsaturated synchronous reactance and armature resistance for the machine
3c) Induction Machine Analysis [ 8 marks ] A 415 V, 50 Hz, 1450 rpm, three-phase, star-connected induction machine has the following equivalent circuit parameters (referred to the stator winding where appropriate) stator resistance R 0.3 ohms, rotor resistance R2 0.2 ohms stator leakage reactance X 2 ohms, rotor leakage reactance X2' 2 ohms magnetising reactance XM 50 ohms, core loss resistance Rc 200 ohms In your calculations, you should use = the simplified equivalent circuit i) Find the number...
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