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. Show Elementary Synchronous Machines?
The polyphase synchronous machine operates with direct current supplied to the field winding (assumed to be on the rotor, which is usually the case) through two slip rings and with polyphase alternating current supplied to the armature (assumed to be on the stator). The rotormmf, which is obtained froma dc source, is stationarywith respect to the rotor structure.When carrying balanced polyphase currents, the armature winding produces a magnetic field in the air gap rotating at synchronous speed, as determined by the system frequency and the number of poles in the machine. But the field produced by the dc rotor winding revolves with the rotor. To produce a steady unidirectional torque, the rotating fields of stator and rotor must be traveling at the same speed. Therefore, the rotor must turn precisely at the synchronous speed.
The polyphase synchronous machine is one in which the rotor rotates in synchronism with and in the same direction as the rotating mmf wave produced by the stator. Thus for synchronous machineswith polyphase statorwinding, the following equation relatingmechanical and electrical angular speeds is satisfied:
or alternatively, the steady-state speed at which the machine operates is known as the synchronous speed, given by
where f is the frequency of the system of which the machine is a part and P is the number of poles of the machine.
Q. Show Applications for DC Machines? Dc motors find wide applications in which control of speed, voltage, or current is essential. Shunt motors with constant speed are used fo
Q. Slip-power controlled wound-rotor induction-motor drives? Slip power is that portion of the air-gap power that is not converted into mechanical power. The methods involving
Q. Three dc generators are operating in parallel with excitations such that their external characteristics are almost straight lines over the working range with the following pairs
Explain the different types of multivibrators ? Multivibrator is basically a two-stage amplifier with output of one supplied back to the input of the other . Multivibr
Classify the following signals as energy signals or power signals. Find the normalized energy or normalized power of each. a. ? ? , 0, 0 0, at Ae t a x t elsewhere
Interrupt Signals There are five interrupt signals in 8085 microprocessor. These signals are used to inter rut the current program under execution and transfer the ex
Consider an S band (3 GHz) radar with a rotating aperture antenna with a width of 3 m. Suppose the antenna rotates at a rate of one rotation every 10 seconds. Assume the 3 dB bea
Q. Athree-phase, 600-kVA, 2300:230-V,Y-Ytrans- former bank has an iron loss of 4400 W and a full- load copper loss of 7600 W. Find the efficiency of the transformer for 70% full lo
Discuss the assembler directive of OFFSET with example. OFFSET: This is an operator to find out the offset (displacement) of a variable or process regarding the base
What are Macros? Macro is a group of instruction. The macro assembler makes the code in the program each time where the macro is called. Macros are described by MACRO & ENDM di
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