Question 3 A WT is a complex machine comprised of multiple mechanical and electrical subsystems, including the main bearing, blades, gear box, and generator, among others. The main bearing is a key subsystem that assists the conversion of wind kinetic energy into mechanical energy. The reliability of the main bearing degrades over time due to wear out of its rolling bolts, and cracks of inner and outer rings races resulted from ball rotations and vibrations. The field data shows that the hazard rate function of the main bearing can be modelled as h (t) = 0.002 failures/year. Estimate (a) Cumulative hazard function. (b) Reliability function (c) Mean Time to Failure (MTTF)

Question 3 A WT is a complex machine comprised of multiple mechanical and electrical subsystems, including the main bearing, blades, gear box, and generator, among others. The main bearing is a key subsystem that assists the conversion of wind kinetic energy into mechanical energy. The reliability of the main bearing degrades over time due to wear out of its rolling bolts, and cracks of inner and outer rings races resulted from ball rotations and vibrations. The field data shows that the hazard rate function of the main bearing can be modelled as h (t) = 0.002 failures/year. Estimate (a) Cumulative hazard function. (b) Reliability function (c) Mean Time to Failure (MTTF)

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

Q2) A wave wound DC generator armature has six - pole and 50 slots. Each slot contains 20 conductors. The required generated voltage is 250 V. a) What would be the speed of the armature, if flux per pole is 0.007 Wb? b) If the armature is rewound as lap formation and run at the same speed you found in part a) above, what will be the generated voltage? The flux per pole is 0.007 Wb.
An electromagnet has a movable iron part and dimensions of magnetic circuit with uniform cross section as shown in figure. The core is made of ferromagnetic material with relative permeability of 3000: a) b) c) Calculate the magnetic reluctance of the circuit and the inductance of the main winding. Determine the air-gap flux, the flux density and the field intensity of the core and gap. Because of a fault in the power supply, the exciting current is increased to 8 A causing the mobile element of the iron core to move to a zero gap position as a result of the excessive electromagnetic force action. If this movement occurs in 0.01 s, find the transient voltage induced in the test coil having two turns. 0.5 mm air-gap 2 cm 2 A 3 cm 2 cm 60 turns 18 cm test coil 24 cm 0.5 mm air-gap
A 100KW generator, 250V, 6 poles have a wave wound armature with 300 turns then the number of compensating winding turns per pole is approximately equal to ----- if the ratio of pole arc/pole pitch * is 0.72
Other than the two main parts of rotating machines.the rotor and stator,enumerate other parts.
a) A triplex lap-wound armature is use in a 14 poles machine with 14 brushes sets, each spanning three commutator bars. Calculate the number of parallel paths in the armature. b) Repeat a) for a triplex wave-wound armature having two such brush sets and 14 poles. c) Calculate the generated emf in each of the above problems, if the flux per pole is 4.2x106 lines, the generated speed is 60rpm, and there are 420 coils in the armature, each coil having 20 turns.
Exercise 2-1: The armature core of a 4 pole de machine has 31 slots each designed to accomodate 4 coil sides of a simplex wave winding. The winding has total of 496 conductors. Find i) Total number of coils ü) Turns per coil i) Commutator pitch iv) Back, front and total pitches v) Number of commutator, segments.
A 2 pole wave wound dc generator has 44 slots, each slot having 20 conductors. The flux/pole is 0.018 weber. At what speed the armature be rotated to get an induced emf of 220 V. What will be the induced emf developed if the armature winding is lap connected and runs at the same speed. Speed Generated Emf when lap connected
A 8 pole wave wound dc shunt generator runs at a speed of 900 rpm, has an armature and shunt field resistance of 0.7 N and 300 N respectively. The armature has 960 conductors and flux per pole is 0.057 Weber. If the lamp load connected has a resistance of 60 2, determine (i) Generated EMF, (ii) Total Resistance, (iii) Armature Current, (iv) Terminal Voltage. Generated EME (Eg) Total Resistance (Rt) Armature Current (la) Terminal Voltage (V)
A 4 pole generator with wave wound armature has 52 slots each having 28 conductors. The flux per pole is 0.01 Wb. (i) At what speed must the armature rotate to give an induced EMF of 225V is, (ii) What will be the voltage developed, if the winding is lap connected and the armature rotates at the same speed is, A shunt generator supplies a 25kW load at 205V through cables of resistance, R = 112mQ. If the field winding resistance, Rf =640 and the armature resistance, Ra =55mQ. Determine the following below: The terminal voltage is, The e.m.f. generated in the armature is, Explain the Commutation process in DC machines.
In a DC machine, provides the magnetic path as well as the mechanical support to the whole machine. Bearings Commutator O Brushes Yoke
Electric Machines2 What are the characteristics of the rotating magnetic field created by three-phase current inthree-phase stator winding?
30. A) Why is there a small emf generated in a series generator at no load? a) the residual magnetic field establishes a low density magnetic field which the armature conductors cut b) the series field does not contribute any magnetic strength, because the field strength is a product of Ampere-Turns and there is no current through the series field with no load c) the amount of emf generated in a series generator is directly proportional to the load current d) all of the above B) What happens to the generated emf as load is added? a) voltage should increase provided the field is connected in the correct polarity b) voltage should decrease regardless of the field connection polarity c) either "a" or "b" d) neither "a" nor "b"