Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Explain the Synchronous Machines?
A synchronous machine, unlike an induction (or asynchronous) machine, only develops torque at a fixed, so called, synchronous speed - ns which is related to the supply frequency f and the number of pole-pairs p as follows:
ns = 60 . f / p
The main application of a synchronous machine is as a generating device for the bulk conversion of mechanical energy (from a gas, steam or water turbine or a diesel engine) to electrical energy. It is therefore found in all types of power generating stations and also standby generating plants. In the case of a steam plant, the machine is often referred to as a turbo-generator, turbine generator or turbo-alternator. Electrical machines are in general reversible in nature meaning that they are capable of operating both as a motor and as a generator. In this sense, the synchronous machine is no exception. A good example of this are pumped-storage hydro-electric schemes such as the one at Dinorwig in North Wales comprising 6 x 315-MW synchronous machines which can be operated as generators or motors. Synchronous motors are more expensive to install than induction motors and are only found in relatively small numbers in industry where there is a requirement both for a constant-speed drive and the ability of reactive power control.
If inverter-fed they can be used in high-speed variable speed drives for traction applications. Small single-phase synchronous motors have been widely used to provide a timing mechanism for processes such as washing machine cycles. A permanent magnet synchronous machine, usually termed as a DC brushless machine, serves as a basis for numerous high performance servo applications for machine tools and industrial robots. The objective of this module is to look at synchronous machines as a central part of a power generation system. In this sense, the following sections will discuss only the fundamental theory of classical synchronous generators and not the machine operating characteristics in motoring mode.
Q. Explain Modulation and sampling? Modulation is the process whereby the amplitude (or another characteristic) of a wave is varied as a function of the instantaneous value of
Supercomputer The largest fastest and most powerful are called supercomputers. Supercomputers are mainly used for weather forecasting remote sensing image processing, biom
Q. Parallel - flash converter? Parallel / flash converter. Also known as parallel A/D converter, this circuit is the simplest to understand. It's formed of a series of co
Q. Show Advantage of digital control system over analog system? Sampled data and digital control offer several advantages over analog systems: • More compact and lightweight
Q. How numbering plan is achieved in modern telephony? Ans: The purpose of numbering plan is to uniquely identify every subscriber connected to a telecommunication network.
Q. With suitable diagram explains the working of a sweep frequency generator. Sol. A sweep frequency generator or sweeper is a special type of signal generator in which the o
Energy band: the energy band picture for Ii an- type, and Iii ap - type semiconductor Indicate the position for, the donor and acceptor levels. Sol.(a)
For a given logic family, consider VOL = 0.25V and VOH = 5 V . For a given circuit, VIL = 0.96 V and VIH = 2.18 V. Find the largest positive-going and largest negative-going nois
The relationship between cell and batteries Generally, a cell delivers a certain voltage that is a function of what chemical reactions are taking place to generate the voltage
defination and working ?
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd