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!
Q. Explain about Elementary Direct-Current Machines?
A preliminary discussion of dc machines, including Equations. The location of the brushes on the commutator arrangement connected to the armature winding ensures that the rotor and stator mmf axes are at all times at right angles to one another, as shown in Figure. The expression for torque given by Equation is applicable to the dc machine, provided the constant K is adjusted for the nonsinusoidal mmf distributions and sin δ is made equal to unity. Not only are the conditions for constant torque fulfilled, but also the condition for maximum torque and hence for maximum energy conversion is satisfied, since δ = ± π/2, depending upon whether generator or motor action occurs for a given direction of rotation.
Since both armature and field circuits carry direct current in the case of a dcmachine, they can be connected either in series or in parallel. When the armature and field circuits are connected in parallel, the machine is known as a shunt machine. In the shunt machine, the field coils are wound with a large number of turns carrying a relatively small current. When the circuits are connected in series, the machine is known as a series machine. The field winding in the series machine carries the full armature current and is wound with a smaller number of turns. A dc machine provided with both a series-field and a shunt-field winding is known as a compound machine. In the compoundmachine, the series fieldmay be connected either cumulatively, so that itsmmf adds to that of the shunt field, or differentially, so that the mmf opposes. The differential connection is used very rarely. The voltage of both shunt and compound generators (or the speed, for motors) is controlled over reasonable limits by means of a field rheostat in the shunt field. The machines are said to be self-excited when the machine supplies its own excitation of the field windings, as in the cases just defined. The field windings may be excited separately from an external dc source, however. A small amount of power in the field circuit can control a large amount of power in the armature circuit. The dc generator may then be viewed as a power amplifier.
a train weight 5 megaN is taking a slope of 1 in 200 at 45 kmper hour.the engine put in 100 kw.determine the power to be put in by the engine it the train take the slope up of 1 in
What are the 8086 interrupt types? Dedicated interrupts Type 0: Divide by zero interrupt Type 1: Single step interrupt Type 2:Non maskable interrupt Type 3: Breakpo
Q. Explain about Floating Point Numbers? The IEEE Standard 754 floating point is the most common representation today for real numbers on computers. There are numerous ways
CURRENTLY, orthogonal frequency division multiplexing (OFDM) is emerging as the preferred modulation technique in modern high data rate broadband wireless mobile communication syst
Q. ADMM (digital multimeter) reads true rms values of current. If the peak value of each of the following periodic current waves is 5 A, find the meter reading for: (a) a sine wave
Software/Application Platform Requirement: GIS solutions would primarily consist of Database and Applications software. The application package should work in LAN/WAN/Interne
Describe in brief how email system works Following is a simple description of how email system works: - Sender composes a message (and attaches a file if required) and send
Q. Open-circuit and load characteristics of generator? The open-circuit and load characteristics of a separately excited dc generator, along with its schematic diagram of conne
CMA Complement Accumulator Instruction Complement the contents of the accumulator i e the accumulator al once are converted zeros and all zeros are converted to ones.
Q. Given that V 0 = 10 V, determine IS in the circuit drawn in Figure.
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