A 225 kW ( 300 hp), 250 V, 1280 r/min de motor has windage, friction, and...
Name: 23. A 3-phase, 5000 hp, 6000 v,60 Hz, 12-pole wound-rotor induction motor has the 1, resistance between stator terminals-o12 Ω 2. resistance between rotor slip-rings-0.0073 Ω 3. windage and friction losses-51 kW following characteristics 4. iron losses in the stator-39 kW 5. locked rotor current at 6000 V-1800 A 6. active power to the stator with rotor locked 2207 kw Calculate under full-load voltage locked-rotor conditions a. Reactive power absorbed by the motor b. FR losses in the stator...
14. The following details are known about a 200 hp, 500 V, 435 rpm de shunt motor: full-load current is 330 A, insulation class is H, weight is 3400 kg, external diameter of the frame is 915 mm and length of the frame is 1260 mm. If the motor is running at full-load, calculate: a. the total losses and efficiency. b, the approximate shunt field exciting current if the shunt field causes 15% of the total losses. the value of...
7. A 3-phase, 300 kW, 2300 V, 60 Hz, 1800 r/min induction motor is used to drive a compressor. The motor has a full- load efficiency and power factor of 93 percent and 87 percent, respectively. If the terminal voltage rises to 2750 V while the motor operates at full-load, determine the effect (increase or decrease) upon a. Mechanical power delivered by the motor b. Motor torque c. Rotational speed d. Full-load current e. Power factor and efficiency f. Starting...
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...
1. A 300 V compound motor has armature resistance 0.18 Ω, series field resistance 0.3 Ω and shunt field resistance 100 Ω. The rotational losses are 200 W. On full load the line current is 25 A and the motor runs at 1800 rpm. Determine: (i) the developed mechanical power (ii) the output power (iii) the output torque (iv) the efficiency at full load 2. A 120 V series motor has 0.2 Ω field resistance. On full load, the line...
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...
RedID: Name: Question 3. (18 Marks) A 10-hp, 130V, series dc motor, shown here, has an armature resistance of 0.1 Ω and a series field resistance of also 0.1. The number of turns of series coil N,-500. At the load 60 A, the speed is 850 r/min. Its magnetization curve is shown below. The core losses are 220 W and the mechanical losses are 230 W at this load. Assume that the mechanical losses vary as the cube of the...
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 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...
Question (3) Speed Control [10 Marks A 50 hp, 220 V, 1500 rpm DC shunt motor with an armature resistance of 0.04 Q and a field resistance of 50 Q. The motor has compensating windings, so armature reactance can be ignored. Mechanical and core losses may be ignored also. The moter is driving a load toque that is proportional with speed, Ti a (n). The motor is driving a load with a line current of 80 A and an initial...