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ing the arhature voltage (with the shunt field voltage held constant) offer a good method of...
A 8250 w shunt DC motor has a terminal voltage of 300 V. A field resistance...
A 8250 w shunt DC motor has a terminal voltage of 300 V. A field resistance Rf of 40 Ω, and an armature resistance Ra of 250 mm2. The field winding has 1500 turns. An adjustable resistance Rad is connected in series to the field winding. Rad is set at 20 Ω, but it can vary from 0 to 80 Ω. The magnetization curve is shown in Figure.1 and it is taken at a speed of 1200 rpm. (Armature reaction...
Choose the correct answer for each question and explain why its right. 1. If it is...
Choose the correct answer for each question and explain why its
right.
1. If it is necessary to reverse the direction of a DC motor, the simplest way to do it is to a. reverse the armature leads b. reverse the polarity of the power supply leads c. add a capacitor between the positive and negative DC voltage leads d. get a reversed wired DC motor In a shunt configured DC motor, the series field is a. attached in series...
3. A 20kW, 250V, 1000rpm shunt excited dc motor has armature and field resistances of 0.2...
3. A 20kW, 250V, 1000rpm shunt excited dc motor has armature and field resistances of 0.2 ohm and 2002. When the motor takes 80A rated current at rated conditions. Draw the equivalent circuit and calculate induced torque at 1200rpm. Explain the starting current limiting methods for DC motors. (30 pts) 4. Explain the conditions for parallel operation of synchronous generators. A three phase, wye connected, synchronous generator is rated 150 MW, 0.85 lagging power factor, 12.6 kV, 60 Hz, and...
QUESTION 1 A) (10 marks) A 10 kW, 250 V DC self-excited shunt generator, with an...
QUESTION 1 A) (10 marks) A 10 kW, 250 V DC self-excited shunt generator, with an armature resistance of 0.1 ohm, is delivering 80 % of rated power to the mains at rated voltage when being run at 1000 r.p.m. (revolutions per minute). The field circuit resistance is 220 ohms. The brush contact drop is 0.5 V and rotational (mechanical) losses are 750 W Calculate The induced voltage The electromagnetic torque developed The shaft torque The overall efficiency B) (15...
2. Why it is dangerous to supply power to an unloaded series connected DC motor? Puerto...
2. Why it is dangerous to supply power to an unloaded series connected DC motor? Puerto Rico Polytechnic University Department of Electrical Engineering Electromechanical Energy Conversion Systems I Laboratory 89 3. How can you reverse the direction of rotation of a shunt DC motor? 4. Name and explain two methods to control the speed of a DC motor.
one of the following is not essential in generating a dc voltage UNIT 1 OPERATING PRINCIPLES...
one of the following is not essential in generating a dc
voltage
UNIT 1 OPERATING PRINCIPLES OF D 8 ng ACHIEVEMENT REVIEW Select the correct answer for each of the following statements, and pl letter in the space provided. I. A generator ace the ce a. changes electrical energy to mechanical energy. b) changes mechanical energy to electrical energy c. is always self excited. d. is always separately excited. One of the following is not essential in generating a DC...
3. A 25-kW, 230-V shunt motor has an armature resistance of 0.064 Ω and a field-circuit...
3. A 25-kW, 230-V shunt motor has an armature resistance of 0.064 Ω and a field-circuit resistance of 95 Ω. The motor delivers rated output power at rated voltage when its armature current is 122 A. When the motor is operating at rated voltage, the speed is observed to be 1150 r/min when the machine is loaded such that the armature current is 69.5 A a. Calculate the rated-load speed of this motor In order to protect both the motor...
Given a 1/4 hp, separately excited, dc motor with the following parameters: K = 0.61, R, 15Ω, La-...
I can not seem to get the right answers. Thank you!
Given a 1/4 hp, separately excited, dc motor with the following parameters: K = 0.61, R, 15Ω, La-120mb. J = 0.005, and b = 0.0006. The armature voltage is controlled by a 120-V dc PWM source operating at 100 Hz 1. What is the armature current if the no-load speed is 1800 rpm when the armature supply is operated at a 100% duty cycle? 2. What is the no-load...
A 230 V shunt direct-current machine on no-load has a speed of 900 rpm and a supply current of 2.5 A. The machine parameters are: • Field resistance: 230 Ω • Armature resistance: 0.3 Ω • Voltage drop/...
A 230 V shunt direct-current machine on no-load has a speed of 900 rpm and a supply current of 2.5 A. The machine parameters are: • Field resistance: 230 Ω • Armature resistance: 0.3 Ω • Voltage drop/brush: 1.0 V (current independent) a) Calculate the electromagnetic torque, speed, the output power and the overall efficiency when the supply current is 35 A, assuming that the friction and wind-age torque is constant. (16 points) b) The machine operates now as generator...
Q1: (30 points) A shunt DC generator, running at a constant speed of 1400 rpm, has...
Q1: (30 points) A shunt DC generator, running at a constant speed of 1400 rpm, has a field resistance of 200 22 and armature resistance of 0.5 12. Ignore armature reaction and assume a 400 W rotational loss. a) [15] While supplying no load, the induced armature voltage is 280 V. Calculate the input power. b) [15] When the generator is loaded, the developed power is found to be 4.1 kW at the same magnetic flux of the field found...
A 8250 w shunt DC motor has a terminal voltage of 300 V. A field resistance Rf of 40 Ω, and an armature resistance Ra of 250 mm2. The field winding has 1500 turns. An adjustable resistance Rad is connected in series to the field winding. Rad is set at 20 Ω, but it can vary from 0 to 80 Ω. The magnetization curve is shown in Figure.1 and it is taken at a speed of 1200 rpm. (Armature reaction...
Choose the correct answer for each question and explain why its
right.
1. If it is necessary to reverse the direction of a DC motor, the simplest way to do it is to a. reverse the armature leads b. reverse the polarity of the power supply leads c. add a capacitor between the positive and negative DC voltage leads d. get a reversed wired DC motor In a shunt configured DC motor, the series field is a. attached in series...
3. A 20kW, 250V, 1000rpm shunt excited dc motor has armature and field resistances of 0.2 ohm and 2002. When the motor takes 80A rated current at rated conditions. Draw the equivalent circuit and calculate induced torque at 1200rpm. Explain the starting current limiting methods for DC motors. (30 pts) 4. Explain the conditions for parallel operation of synchronous generators. A three phase, wye connected, synchronous generator is rated 150 MW, 0.85 lagging power factor, 12.6 kV, 60 Hz, and...
QUESTION 1 A) (10 marks) A 10 kW, 250 V DC self-excited shunt generator, with an armature resistance of 0.1 ohm, is delivering 80 % of rated power to the mains at rated voltage when being run at 1000 r.p.m. (revolutions per minute). The field circuit resistance is 220 ohms. The brush contact drop is 0.5 V and rotational (mechanical) losses are 750 W Calculate The induced voltage The electromagnetic torque developed The shaft torque The overall efficiency B) (15...
2. Why it is dangerous to supply power to an unloaded series connected DC motor? Puerto Rico Polytechnic University Department of Electrical Engineering Electromechanical Energy Conversion Systems I Laboratory 89 3. How can you reverse the direction of rotation of a shunt DC motor? 4. Name and explain two methods to control the speed of a DC motor.
one of the following is not essential in generating a dc
voltage
UNIT 1 OPERATING PRINCIPLES OF D 8 ng ACHIEVEMENT REVIEW Select the correct answer for each of the following statements, and pl letter in the space provided. I. A generator ace the ce a. changes electrical energy to mechanical energy. b) changes mechanical energy to electrical energy c. is always self excited. d. is always separately excited. One of the following is not essential in generating a DC...
3. A 25-kW, 230-V shunt motor has an armature resistance of 0.064 Ω and a field-circuit resistance of 95 Ω. The motor delivers rated output power at rated voltage when its armature current is 122 A. When the motor is operating at rated voltage, the speed is observed to be 1150 r/min when the machine is loaded such that the armature current is 69.5 A a. Calculate the rated-load speed of this motor In order to protect both the motor...
I can not seem to get the right answers. Thank you!
Given a 1/4 hp, separately excited, dc motor with the following parameters: K = 0.61, R, 15Ω, La-120mb. J = 0.005, and b = 0.0006. The armature voltage is controlled by a 120-V dc PWM source operating at 100 Hz 1. What is the armature current if the no-load speed is 1800 rpm when the armature supply is operated at a 100% duty cycle? 2. What is the no-load...
Q1: (30 points) A shunt DC generator, running at a constant speed of 1400 rpm, has a field resistance of 200 22 and armature resistance of 0.5 12. Ignore armature reaction and assume a 400 W rotational loss. a) [15] While supplying no load, the induced armature voltage is 280 V. Calculate the input power. b) [15] When the generator is loaded, the developed power is found to be 4.1 kW at the same magnetic flux of the field found...
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