A 3-phase, 460 V, 1740 rpm, 60 Hz, 4-pole wound-rotor induction
motor has the
following parameters per phase: R1 = 0.25 Ω, '
2R = 0.2Ω, '
1 2 X = X = 0.5Ω, 30 m X = Ω.
The rotational losses are 1700 W. With the rotor terminals
short-circuited, find:
1. at starting:
• current when started direct on full voltage,
• a torque
2. at full load:
• slip
• current
• ratio of starting current to full-load current
• power factor
• torque
• internal efficiency and motor efficiency
3. maximum torque and slip at this torque
4. how mach external resistance per phase should be connected in
the rotor
circuit so that maximum torque occurs at start?
A 3-phase, 460 V, 1740 rpm, 60 Hz, 4-pole wound-rotor induction motor has the following parameters...
A 500 hp, three-phase, 2200 V, 60 Hz, 12-pole, Y-connected, wound-rotor induction motor has the following parameters: 5.9 0.225 Ω x, R, R',-0.235 Ω X, 31.8 Ω R""-780 Ω 1.43 Ω Calculate the following: a. Slip at maximum torque b. Input current and power factor at maximum torque c. Maximum torque d. Resistance that must be added to the rotor windings (per phase) to achieve maximum torque at starting
1) One phase equivalent parameter of a three-phase, 460V, 1740d / d, 60Hz, 4-pole, rotor wound asynchronous motor values are given below. R1 = 0.25Ω, R’2 = 0.2Ω, X1 = X’2 = 0.5Ω, Xm = 30Ω Rotary losses are 1700W. While the rotor terminal ends are short-circuited, find the following requirements. a) (i) Find the starting current when the motor is supplied with nominal voltage? (ii) Find the starting torque? b) (i) Find the slip at full load? (ii) Find...
Consider a 50 kW, 3-phase, 380 V line-to-line, 50 Hz, 6 pole Y-connected wound-rotor induction motor. The stator winding ac resistance is 0.1 Ω/phase. The effective stator-to-rotor turns ratio is 2. The exciting branch is negligible. It is found that when an external resistor of 0.09 Ω/phase is connected to the rotor terminals maximum starting torque of 1150 Nm is obtained. a. Compute the internal mechanical power and the internal torque developed by this motor when it drives a load...
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...
. A 460-V 460-V, 25-hp, 60-Hz, six-pole, Y-connected induction motor has the following impedanc ohms per phase referred to the stator circuit. Ri= 0.212 R2 = 0.282 X1 = 1.055 12 X2 = 1.055 22 XM = 33.9 W The total rotational losses are 1100 W and are assumed to be constant. The core loss is lumped with the rotational losses. For a rotor slip of 4% at the rated voltage and rated frequency, a) The input power b) Peony...
4.6. A 460-V, 75 kW, 4-pole, delta-connected, 60-Hz, three- phase induction motor has a full-load slip of 5 percent, an efficiency of 92 percent and a power-factor of 0.87 lagging at full-load. At start-up, the motor develops 1.9 times the full load developed torque but draws 7.5 times the rated current at the rated voltage. This motor is to be started with an auto- transformer reduced-voltage starter. Assume the stator resistance and the stator core loss to be negligible. Calculate...
Problem 3 A three-phase, 230-V, 60-Hz, 12-kW, four-pole wound-rotor induction motor has the following parameters expressed in Ω/phase. R 0.095; 0.680; Xs 0.672; Xm 18.7. Using MATLAB, plot the electromagnetic torque as a function of rotor speed in rot/min for rotor resistances of R -0.1, 0.2,0.5, 1.0 and 1.5 .
5. A 208-V four-pole 60-Hz Y-connected wound-rotor induction motor is rated at 30 hp. Its equivalent circuit components are R=0.100 Ry=0.070. X - 10.00 R = 250 X; -0.2100 X=0.21002 Praw=500 W P =0.5% of input at full load For a slip of 0.05, find (a) The line current (b) The induced voltage in the rotor (c) The stator power factor (d) The rotor power factor (e) The rotor frequency (f) The stator copper losses (g) The core loss (h)...
2. A 208V, two pole, 60 Hz, y connected wound rotor induction motor is rated at 15hp. Its equivalent circuit parameters are R:-0.200, R:-0.120, X.-X-0.410, X-150. The rotational losses are 430W. The motor drives a mechanical load with a slip of 5 percent. By using simplified equivalent circuit calculate; (30 pts) a) The motor speed in revolutions per minute and radians per second. b) The line current c) The stator copper losses. d) The air gap power. e) The power...
A 230 V, 50 Hz, three-phase, Y-connected, 6-pole induction motor has the following per-phase parameters R-0.07 Ro 00 0.08 Ω x, x, 0.3 xm 6.33 At a slip of 2%, determine the followings using approximate equivalent circuit of the motor i) The motor speed in rev/min and rad/s. ii) The rotor current. ii) The stator current. iv) The induced torque. v) The efficiency of the motor.