Recent questions tagged electrical-machines

A $4$-pole induction motor with inertia of $0.1\; kg-m^{2}$ drives a constant load torque of $2\; Nm$. The speed of the motor is increased linearly from $1000$ $\text{rpm...

A star-connected $3$-phase, $400\; V$, $50$ $\text{ kVA}$, $50\; Hz$ synchronous motor has a synchronous reactance of $1$ $\text{ohm}$ per phase with negligible armature ...

A $3$-phase, $415\; V$, $4$-pole, $50\:Hz$ induction motor draws $5$ times the rated current at rated voltage at starting. It is required to bring down the starting curre...

Consider the table given:$\begin{array}{|cl|cI|cI|}\hline&\textbf{Constructional feature} & \textbf{Machine type} & \textbf{Mitigation} \\ \hline &\text{P. Damper bars} ...

The power input to a $\text{500 V, 50 Hz, 6-pole, 3-phase}$ induction motor running at $975 \text{RPM}$ is $40 \text{ kW}$ . The total stator losses are $1 \text{ kW}$. I...

An alternator with internal voltage of $1\angle \delta _{1}\text{p.u}$ and synchronous reactance of $\text{0.4 p.u}$ is connected by a transmission line of reactance $\te...

​​​​​​​In a single-phase transformer, the total iron loss is $2500\:W$ at nominal voltage of $440\:V$ and frequency $50\:Hz$. The total iron loss is $850\:W$ at $220\:V$ ...

A belt-driven $\text{DC}$ shunt generator running at $300\: \text{RPM}$ delivers $100 \:\text{kW}$ to a $200 \:V\: \text{DC}$ grid. It continues to run as a motor when th...

An $8$-pole, $50 \:Hz$, three-phase, slip-ring induction motor has an effective rotor resistance of $0.08\:\Omega$ per phase. Its speed at maximum torque is $650 \text{ R...

An air-core radio-frequency transformer as shown has a primary winding and a secondary winding. The mutual inductance $M$ between the windings of the transformer is _____...

A three-phase cylindrical rotor synchronous generator has a synchronous reactance $X_{s}$ and a negligible armature resistance. The magnitude of per phase terminal voltag...

A three-phase, $\text{50 Hz}$, $4$-pole induction motor runs at no-load with a slip of $1\%$. With full load, the slip increases to $5 \%$. The $\%$ speed regulation of t...

A single-phase, $\text{4 kVA}$, $200\: V/100 \: V$, $50 \: Hz$ transformer with laminated $\text{CRGO}$ steel core has rated no-load loss of $450 \: W$. When the high-vo...

A $250 V$ dc shunt motor has an armature resistance of $0.2\:\Omega$ and a field resistance of $100\:\Omega$. When the motor is operated on no-load at rated voltage, it d...

Consider a permanent magnet dc $\text{(PMDC)}$ motor which is initially at rest. At $t=0$, a dc voltage of $5 V$ is applied to the motor. Its speed monotonically increase...

The figure below shows the per-phase Open Circuit Characteristics (measured in $\text{V}$) and Short Circuit Characteristics (measured in $\text{A}$) of a $14 \: kVA$, $4...

A cylindrical rotor synchronous generator with constant real power output and constant terminal voltage is suppling $100 \: A$ current to a $0.9$ lagging power factor loa...

Windings $\text{‘A’,’B’}$ and $\text{‘C’}$ have $20$ turns each and are wound on the same iron core as shown, along with winding $\text{‘X’}$ which has $2$ turns. The fig...

A cylindrical rotor synchronous generator has steady state synchronous reactance of $0.7 \: pu$ and subtransient reactance of $0.2 \: pu$. It is operating at $\left ( 1+j...

A $5kVA, 50V/100V,$ single-phase transformer has a secondary terminal voltage of $95V$ when loaded. The regulation of the transformer is$4.5\%$$9\%$$5\%$$1\%$

The parameter of an equivalent circuit of a three-phase induction motor affected by reducing the rms value of the supply voltage at the rated frequency isrotor resistance...

A three-phase synchronous motor draws $200 A$ from the line at unity power factor at rated load. Considering the same line voltage and load, the line current at a power f...

A single-phase transformer of rating $25$ kVA, supplies a $12$ kW load at power factor of $0.6$ lagging. The additional load at unity power factor in kW (round off to two...

A $220$ V DC shunt motor takes $3$ A at no-load. It draws $25$ A when running at full-load at $1500$ rpm. The armature and shunt resistance are $0.5 \: \Omega$ and $220 \...

A delta-connected, $3.7$ kW, $400$ V(line), three-phase, $4$-pole, $50$-Hz squirrel-cage induction moor has the following equivalent circuit parameters per phase referred...

A $220$ V(line), three-phase, Y-connected, synchronous motor has a synchronous impedance of $(0.25+j2.5) \: \Omega/\text{phase}$. The motor draws the rated current of $10...

A single phase $10$ kVA, $50$ Hz transformer with $1$ kV primary winding draws $0.5$ A and $55$ W, at rated voltage and frequency, on no load. A second transformer has a ...

The locked rotor current in a $3$-phase, star connected $15$ kW, $4$-pole, $230$ V, $50$ Hz induction motor at rated conditions is $50$ A. Neglecting losses and magnetizi...

A $220$ V, $15$ kW, $1000$ rpm shunt motor with armature resistance of $0.25 \: \Omega$, has a rated line current of $68$ A and a rated field current of $2.2$ A. The chan...

The slip of an induction motor normally does not depend onrotor speedsynchronous speedshaft torquecore-loss component