Recent questions tagged electrical-machines

A $15 \mathrm{kVA}, 1100 \mathrm{~V} / 220 \mathrm{~V}$, single-phase two-winding transformer is configured as a $1.32 \mathrm{kV} / 1.1 \mathrm{kV}$ autotransformer.What...

A certain application requires power at a frequency of $16.67$ Hz, while the available grid frequency is $50$ Hz. A $3$-phase synchronous motor connected to the $50$ Hz, ...

Which one of the following options is correct regarding the typical double-squirrel-cage structure used in induction motors?At starting, a larger portion of the rotor cur...

The figure shows the single-line diagram of a synchronous generator delivering $P =50 \mathrm{~MW}$ of power at unity power factor to an infinite bus.$I_{S}$ denotes the ...

A $220 \mathrm{~V} / 12 \mathrm{~V}$ single-phase transformer is designed for use in India and rated $100$ VA at $50$ Hz. Later, this unit is shipped to the USA where it ...

A balanced three-phase supply is given to a $30 \mathrm{~kW}, 4$-pole, $400 \mathrm{~V}, 50 \mathrm{~Hz}$, wound rotor induction motor with Y-connected stator and rotor w...

The operating region of the developed torque $\left(T_{e m}\right)$ and speed $(\omega)$ of an induction motor drive is given by the shaded region $OQRE$ in the figure. T...

The induced emf in a $3.3 \: \mathrm{kV}, 4$ pole, $3$-phase star connected synchronous motor is considered to be equal and in phase with the terminal voltage under no lo...

The transformer connection given in the figure is part of a balanced $3$-phase circuit where the phase sequence is " $a b c$ ". The primary to secondary turns ratio is $2...

A $\mathrm{DC}$ series motor with negligible series resistance is running at a certain speed driving a load, where the load torque varies as cube of the speed. The motor ...

A $3$-phase, $400 \mathrm{~V}, 4$ pole, $50 \: \mathrm{Hz}$ star connected induction motor has the following parameters referred to the stator:$$R_{r}^{\prime}=1 \Omega, ...

​​​​A $3$-phase, $11 \mathrm{kV}, 10 \mathrm{MVA}$ synchronous generator is connected to an inductive load of power factor $(\sqrt{3} / 2)$ via a lossless line with a per...

​​​​Which of the following options is/are correct for the Automatic Generation Control (AGC) and Automatic Voltage Regulator (AVR) installed with synchronous generators?A...

A $3$-phase star connected slip ring induction motor has the following parameters referred to the stator:\[R_{s}=3 \Omega, X_{s}=2 \Omega, X_{r}^{\prime}=2 \Omega, R_{r}^...

The following columns present various modes of induction machine operation and the ranges of slip$$\begin{array}{ll} \qquad \qquad\textbf{A} & \qquad \textbf{B} \\ \quad...

The four stator conductors $\left(\mathrm{A}, \mathrm{A}^{\prime}, \mathrm{B}\right.$ and $\left.\mathrm{B}^{\prime}\right)$ of a rotating machine are carrying $\mathrm{D...

A separately excited $\text{DC}$ motor rated $400 \mathrm{~V}, 15 \mathrm{~A}, 1500\mathrm{~ RPM}$ drives a constant torqueload at rated speed operating from $400 \mathrm...

A three-phase synchronous motor with synchronous impedance of $0.1+\mathrm{j} 0.3 \text { per unit } $ per phase has a static stability limit of $2.5 \text { per unit.}$ ...

A three phase $415 \mathrm{~V}, 50 \mathrm{~Hz}, \text { 6-pole, } 960 \text { RPM, 4 HP}$ squirrel cage induction motor drives a constant torque load at rated speed oper...

When the winding $\text{c-d}$ of the single-phase, $50 \mathrm{~Hz},$ two winding transformer is supplied from an $\mathrm{AC}$ current source of frequency $50 \mathrm{~H...

The type of single-phase induction motor, expected to have the maximum power factor during steady state running condition, issplit phase (resistance start).shaded pole.ca...

The frequencies of the stator and rotor currents flowing in a three-phase $8$-pole induction motor are $40\:Hz$ and $1\:Hz$, respectively. The motor speed, in $\text{rpm}...

A $20$ $\text{MVA}$, $11.2$ $\text{kV}$, $4$-pole, $50$ $\text{Hz}$ alternator has an inertia constant of $15$ $\text{MJ/MVA}$. If the input and output powers of the alte...

A $280 \;V$, separately excited $\text{DC}$ motor with armature resistance of $1\:\Omega$ and constant field excitation drives a load. The load torque is proportional to ...