Which of the following statements regarding the wind turbine gearbox are true? Select one or more: O a. After the gearbox, the rotational speed of the shaft is slower than the rotational speed of the turbine rotor (= blades). b. There are typically one planetary gear + 2 helical stages O c. With a single planetary stage, a 1: 6 gear ratio can be achieved. Od. The gearbox is usually 4-speed

Which of the following statements regarding the wind turbine gearbox are true? Select one or more: O a. After the gearbox, the rotational speed of the shaft is slower than the rotational speed of the turbine rotor (= blades). b. There are typically one planetary gear + 2 helical stages O c. With a single planetary stage, a 1: 6 gear ratio can be achieved. Od. The gearbox is usually 4-speed

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

See similar textbooks

Similar questions

5- The rotor voltage per phase of a slip-ring star connected induction motor is 289.5 V. The rotor resistance and standstill leakage reactance are 50 and 8 ohm per phase respectively. Determine. (i) the rotor current and power factor at start with slip-rings shorted (ii) the rotor current and power factor at 4% slip with slip-rings shorted (iii) the external rotor resistance per phase required to obtain a starting current of 20 A in the rotor lines.
G-1). The 3-phase squirrel-cage induction motor has a poorer starting torque than might be expected based on the line current being drawn, because the rotor current and stator currents are out of phase as a result of the high rotor frequency at starting. a) true b) false G-2). Which of the following is/are a general method of starting squirrel-cage motors? a) full voltage starting b) reduced voltage starting c) both a" and "b" d) neither "a" nor 'lb" G-3). What is, if any, an objection to building a 3-phase squirrel-cage induction motor with high enough rotor resistance to provide good starting torque? a) stator current would increase b) speed regulation would get poorer c) rotor current would increase d) none of the above G-4). Which code letter(s) is given to the rotor of a 3-phase squirrel cage induction motor with the highest resistive value? a) A b) B-E c) F-V d) none of the above
1. A self-excited induction generator driven by wind turbine, Explaing the relationship between the power supplied by the generator with the variation of wind speed? 2. Explain the starting of 3 phase slip ring induction motor.
Problem 1 The rotor resistance and reactance of a squirrel-cage induction motor rotor at standstill are 0.14 ohm per phase and 0.8 ohm per phase respectively. Assuming a transformer ratio of unity, from the eight-pole stator having a phase voltage of 254 at 60 Hz to the rotor secondary, calculate the following A. rotor starting current per phase. B. the value of slip producing maximum torque.
1.1. A 3-phase, 10 MVA, Salient Pole, Synchronous Motor is run off an 11 kV supply at 50Hz. The machine has Xd = 0.8 pu and Xq = 0.4 pu (using the Machine Rating as the base). Neglect the rotational losses and Armature resistance. Calculate 1.1.1. The maximum input power with no field excitation. 1.1.2. The armature current (in per unit) and power factor for this condition.
1
A/ A460 V, 25 HP, 60 Hz, 4 pole, X-coun- IM. Find' The useful torque and motor efficiency at rated Slip of 2.2% if the total motor impedance at Thise slip is 14/33.6°52 and total rotational losses are loow (R₁ = 0.64-52). B/ Explain the effect of voter resistance of motor output forque.
The following figure shows the circuit of a DC drive system. Choose the right expression concerning this system. Forward bridge Reverse bridge L1 L1 L2 L3 23 Armature Shunt field L3 23 L2 O a. This drive is a Regenerative DC drive. It allows controlling the motor speed ONLY below its base speed. Changing the rotation direction requires to feed the motor from the reverse bridge. The reverse bridge is also used while braking to transform the excess energy into AC and feed it to grid lines O b. This drive is a Non-regenerative DC drive. It allows controlling the motor speed below and above its base speed. Changing the rotation direction requires external contactors to be connected. The reverse bridge is used while braking to direct the excess energy to braking resistor bank Oc. None of the choices Od. This drive is a Regenerative DC drive. It allows controlling the motor speed below and above its base speed. Changing the rotation direction requires to change the pulses fed into the…
A 480 V, 3-phase, 50 Hz, 6-pole, slip-ring, Y-connected induction motors has the following parameters: R3-R2-0.19 Ohm and Xeg-0.33 Ohm The motor speed at full load is 970 rpm. If the magnetizing current is neglected, calculate the maximum torque Answer: The main task of power electronics is to control and convert electrical power from one form to another form Select one: Oa. True O b. False The field and armature resistances of a 231V series motor are 0.1 ohm and 0.2 ohm, respectively. The motor takes line current of 32 A while running at speed of 700 rpm. If the total iron and friction losses are 428 W, determine the motor efficiency in percent. Answer:
I need help on parts 4 and 5. Also, i am confused on computing the output torque.
At 1170 rpm, a three-phase IM generates 4 kilowatt. It is a 6 pole, 60 Hz transformer. Friction and windage losses aren't taken into account. If the stator losses are 250 w, the stator input power will be? * Your answer The gross power of a single phase induction motor absorbed by the backward and the forward fields are 30 w and 160 w respectively. the motor runs at speed of 950 rpm. the no-load frictional losses are 70 w. if the number of poles are 6 and the supply frequency is 50 Hz, the shaft torque will be: * 0.583 0.564 0.578 none of the mentioned 0.835 0.538