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.
Q. explain the architecture of SS7 and compare with seven-layer OSI architecture. Ans: A block schematic diagram of CCITT no. 7 signalling system is displayed in figure. Sig
LIFO (Last In First Out) stack is used in 8085.In this type of Stack the last kept information can be retrieved first.
Q. What are the various types of amplifiers? Amplifiers can be classified as follows: (a) Based on the transistor configuration 1. Common emitter amplifier 2. Common c
Q. J and K are the external inputs to the JKFF shown in Figure. Note that gates 1 and 2 are enabled only when the clock pulse is high. Consider the four cases of operation and expl
Q. For themagnetic circuit shown in Figure, neglecting leakage and fringing, determine the mmf of the exciting coil required to produce a flux density of 1.6 T in the air gap. Them
Explain SAR instructions in 8086 family with example and their effect on flag. SAR: Shift each bit of operand right through given number of bits, this instruction shifts eve
Q. Can you explain Noninverting Amplifier? It is called "noninverting" because there is no sign inversion. A typical circuit is shown in Figure. With a finite op-amp gain Ao,
With neat diagram indicate how a simple NAND gate decoder is used to select a 2716 EPROM memory component for memory locations FF800H-FFFFFH. Simple NAND gate Decoder: As the 2
transformer voltage induced in armatur of ac commentator machin in case tha field flux in sinosoidal?..
Classification of measures: measures or metrics can be classified under the following headings: 1 finance: income shareholder value added value rates of return costs. 2 outp
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