Valves – Troubleshooting and repair
A control valve is a valve used to control fluid flow by varying the size of the flow passage as directed by a signal from a controller





This enables the direct control of flow rate and the consequential control of process quantities such as pressure, temperature, and liquid level.
In automatic control terminology, a control valve is termed a “final control element”.
More about valves
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Mechanical Design of Electric Motors
Suitable for motor designers, engineers, and manufacturers, as well as maintenance personnel, undergraduate and graduate students, and academic researchers, Mechanical Design of Electric Motors provides in-depth knowledge of state-of-the-art design methods and developments of electric motors. From motor classification, design of motor components, model setup, and material and bearing selections to power losses, motor cooling, design integration, vibration, and acoustic noise, this comprehensive text covers the fundamentals, practical design and design-related issues, modeling and simulation, engineering analysis, manufacturing processes, testing procedures, and performance characteristics of electric motors today.
Focusing on the mechanical design of modern electric motors, the book:
Details the design and manufacture of major components and subsystems, such as rotors, shafts, stators, and frames
Reviews various cooling techniques, including forced air, liquid, and phase-change
Discusses the analysis and calculation of motor power losses
Addresses motor vibration and acoustic noise issues
Presents engineering analysis methods and case study results
Emphasizes construction, optimization, and applications
Featuring research results from the author’s own personal experience and the significant contributions of others, Mechanical Design of Electric Motors highlights innovative and advanced electric motors developed in recent decades.

Mechanical Design of Electric Motors
The book also covers the various testing methods of d.c. motors such as Swinburne's test, brake test, retardation test, field test and Hopkinson's test. The book further explains the three phase induction motors in detail. It includes the production of rotating magnetic field, construction, working, effect of slip, torque equation, torque ratios, torque-slip characteristics, losses, power flow, equivalent circuit, effect of harmonics on the performance, circle diagram and applications. This chapter also includes the discussion of induction generator. The book teaches the various starting methods and speed control methods of three phase induction motors. The book incorporates the explanation of various single phase induction motors. The chapter on synchronous motor provides the detailed discussion of construction, working principle, behavior on load, analysis of phasor diagram, Vee and Inverted Vee curves, hunting, synchronous condenser and applications. The book also teaches the various special machines such as single phase commutator motors, universal motor, a.c. servomotor, linear induction motor and stepper motors. The book uses plain, lucid language to explain each topic. The book provides the logical method of explaining the various complicated topics and stepwise methods to make the understanding easy. Each chapter is well supported with necessary illustrations, self explanatory diagrams and variety of solved problems. The book explains the philosophy of the subject which makes the understanding of the concepts very clear and makes the subject more interesting.
