20) This type of motor may used for power factor correction: A) wound-rotor induction B) brushless...
A 3 phase squirrel cage induction motor is connected to a variable speed drive. The motor should be rated for : A. dc duty B. Brushless operation C. Design E D. Inverter duty
The starting torque of a three-phase synchronous motor is increased when SE O ou h atic tio co e rotor electromagnet is turned on. a. b. the rotor electromagnet is turned off. c, the power factor of the ac power network is unity. d. dc power is applied to one of the stator windings. 2. When a synchronous motor without load is connected to a three-phase ac power network, the resulting power factor depends on a. the speed of the...
A wound rotor, induction motor has a rotor resistance of 0.6 ohms per phase and a rotor leakage reactance of 8 ohms . a) What is the operating speed (rpm) of this 2-pole induction motor fed from a 50 Hz supply if the slip is 5%? b) If maximum torque occurs when R2 = sX2, what is the slip at maximum torque? c) What resistance must be added to the rotor circuit to give maximum starting torque?
5. (a) State the reason(s) for using a starter to start an induction motor. b) Describe, with the aid of diagram(s), two methods for starting of a squirrel cage induction (c) The results of no-load and blocked-rotor test on a 3-phase, star-connected induction motor are as follows No-load test: Line-to-Line voltage = 380V: Input power = 1500W: Block-rotor test: Line-to-Line voltage 38V; Input power - 2.4kW Input current-15A; Friction and windage losses is 500W Input current-65A. Stator resistance between terminal...
A three-phase induction motor delivers 500 hp at an efficiency of 0.91, the operating power factor being 0.76 lagging. A loaded synchronous motor with a power consumption of 100 kW is connected in parallel with the induction motor. Calculate the necessary kVA and the operating power factor of the synchronous motor if the overall power factor is to be unity. Answer should be 365 kVA, 0.274
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
a 3 phase 440v induction motor has produced an output power of 75 hp and full load efficiency of 91% and power factor of 83%. A calculate nominal line current B if stator resistance per phase is .1omh what are copper losses at stator ? C if losses are 1.2 kw what is power delivered to rotor d determine i2r losses in rotor . E what is slip f synchronous speed is 1800 rpm what is the speed of motor
6. A 3-phase 2.2 kV 25 Hz squirrel cage induction motor draws a line current of 224 A and a total power of 777 kW when operating at full load. The full-load speed is 245 rpm. The stator is wye connected and has an effective resistance per phase of 0.125 Ω. The stator iron (core) loss is 8.88 kW; friction and windage losses are 4.54 kW. Calculate at full-load conditions: b. power supplied to the rotor, a. the power factor;...
In a shunt-wound dc motor with the field coils and rotor
connected in parallel (see the figure (Figure 1)), the resistance
Rf of the field coils is Rf = 103 Ω and the resistance Rr of the
rotor is Rr = 5.5 Ω. When a potential difference of V = 120 V is
applied to the brushes and the motor is running at full speed
delivering mechanical power, the current supplied to it is 4.90
A.
Part A.) What is...
1. A six pole, 240V, 50 Hz three phase squirrel-cage induction motor has a no-load speed of 103 rad/s and a speed regulation of 5% at rated load. Find the amount of slip (in rpm) at full load for this motor. 2.. A 2 HP, 240 VAC, 60 Hz, capacitor-start motor is 75% efficient and draws 10 A at full load. What is this motor's power factor at rated load? 3. A wound rotor, 3 phase induction motor in Mr....