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The operation principle of AC motors can be explained by using Arago's disk.
(d) actual power is more than its reactive power
(a) the big size of the inductor
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(a) very near to inductive load Power factor of electric bulb is (a) 360°
(d) Resistance Ans: b, 27. (c) increase in temperature (c) depends upon the magnitude of C (d) high (c) A coil with large distributed capacitance (c) reactive power is more than the actual power
Ans: a, 2. Form factor for a sine wave is (c) consume more power (b) to maximise the utilization of the capacities of generators, lines and transformers value of a sinusoidal A.C. current is equal to its value at an angle of______degrees. Download PDF. (d) depends upon the magnitude of R, Land C
RPM If frequency is increased to 100 Hz, reactance becomes_____ohms.
All Rights Reserved. (d) unity
(a) current is maximum (a) 0.5 of peak value (d) 50 Hz (c) make assembly cheap and easier (a) 127.4 V Ans: a, 57.
In any A.C. circuit always
(b) increases with the increase of inductance and the increase of resistance (c) between 180° and 270° (d) kVAR (a) falls to 36.8% of its final steady value (d) zero AC Motor Fundamentals 1.
(d) at all the time of operation
The r.m.s. Easily operate AC motors by connecting the motor to an AC power supply. the car cooler, car air conditioner and auto air conditioner for the sake of a more comfortable environment. Inductance of coil (d) none of the above (c) power Ans: c, 82.
(c) at the time of turning on and off
(b) 100 Hz (c) 40 Hz (a) directly as the cross-sectional area of magnetic core (d) all above The power factor at resonance in R-L- C parallel circuit is (d) Triangular wave Business Hours - Monday to Friday, 8:30am EST to 5:00pm PST. (c) 10 s If a sinusoidal wave has frequency of 50 Hz with 30 A r.m.s. Ans: a, 89. (d) none of the above Current from the power supply ﬂows directly to the main winding.
Download AC/DC Fundamentals - content.myodesie.com book pdf free download link or read online here in PDF. value of pure cosine function is
For the same peak value, which of the following wave has the least mean value ? 1. In the case of an unsymmetrical alternating current the average value must always be taken over The N pole and S pole electromagnets are a simpliﬁed model of the stator. Ans: b, 7. Ans: b, 66. (b) current leads the voltage by 90° Ans: b, 12. In a circuit containing R, L and C, power loss can take place in Ans: c, 87. Once the motor stops, overrun can be signiﬁcantly reduced compared to an induction motor.
(b) 90° Ans: a. Ans: a, 15. circuit in resonance will
(c) 282.8 V (6) will change the resonance frequency
(d) any where
(c) resistance only Ans: c, 58. When operating with a single-phase power supply, we use a phase advancing capacitor to generate a waveform close to a two-phase power supply and generate a rotating magnetic ﬁeld. (d) will increase the selectivity of the circuit (d) none of the above (a) 25% of maximum value (a) the more heat than produced by A.C. when flowing through the same circuit (d) due to all above reasons Pure inductive circuit takes power from the A.C. line when, (a) applied voltage decreases but current increases, (b) applied voltage increases but current decreases, (c) both applied voltage and current increase, (d) both applied voltage and current decrease, (a) power is consumed in resistance and is equal to I R, (b) exchange of power takes place between inductor and supply line, (c) exchange of power takes place between capacitor and supply line, (d) exchange of power does not take place between resistance and the supply line, 15.
Power factor of the following circuit will be zero For a sine wave with peak value Imax the r.m.s. (a) average value/r.m.s.
In a pure capacitive circuit if the supply frequency is reduced to 1/2, the current will (b) 50% of maximum value Ans: d, 47. cm, Speed:
Inductance affects the direct current flow, 8.
(d) ratio of useful current to total cur¬rent Iw/I (c) the current flowing in the inductor (a) very low The rotation speed of the copper disk will be slightly slower than that of the magnet.
(b) directly as square of number of turns
AC Fundamentals By Anu Singla Associate Professor Department of EE Chitkara University, Punjab AC Fundamentals By Anu Singla Associate Professor Department of EE Chitkara University, Punjab 2. (c) resistance Which of the following statements pertains to resistors only ?
(d) capacitance (d) exhibit unwanted inductive and capacitive effects Awesome sir, kindly send me MCQ,s on me email id, i will be very thankful to you for this kindness. (c) increases with the decrease of inductance and decrease of resistance (d) frequency
(b) inductive (a) ratio of net reactance and impedance (b) square wave (a) r.m.s. Low cost start-up is possible. ③Voltage is applied to the main winding, voltage is not applied to the auxiliary winding. In a sine wave the slope is constant
(b) be doubled AC motors are electric motors that rotate by using power from a commercial AC power supply. The best place to install a capacitor is, (b) across the terminals of the inductive load, (b) does not take power at all from a line, (c) takes power from the line during some part of the cycle and then returns back to it during other part of the cycle, 7. AC circuit fundamentals are covered including inductive and capacitive circuits. AC can come in a number of forms, as long as the voltage and current are alternating. Ans: a, 68. 2.
(c) medium In a pure inductive circuit (b) kVA Provide the reader with a case study on the design and optimisation of an air-conditioning (A/C) system.
(d) 16 kVAR
(b) the current flowing in capacitor
The following ﬁgure shows the construction of a standard AC motor.
(c) both resistance and inductance carry equal currents In phase with the current b. Flange bracket die cast aluminum bracket with a machined ﬁnish, press-ﬁtted into the motor case, 2. My friends are so mad that they do not know how I have all the high quality ebook which they do not!
In each of the three coils of a three phase generator, an alternating voltage having an … The reactive power in the circuit is
(c) The equivalent resistance is greater than any one of the resistors DC → does NOT change with time. (d) 64 kW If there is a survey it only takes 5 minutes, try any survey which works for you. (d) increases with decrease of inductance and increase of resistance (b) 5 (b) both will reach their maximum values at the same instant Wire-wound resistors are unsuitable for use at high frequencies because they, (b) are likely to melt under excessive eddy current heat, (d) exhibit unwanted inductive and capacitive effects, 20.
Ans: b, 103. At very low frequencies a series R-C circuit behaves as almost purely
First, prepare a round copper plate that can rotate freely and a magnet. (a) zero
In particular, if a coil rotates in the presence of a magnetic field, the induced emf varies sinusoidally with time and leads to an alternating current (AC), and provides a source of AC power. (d) reactive power is more than actual power
firstname.lastname@example.org, Sir please send me all electrical pdf questions my, Sir please send me all Electrical questions to my Email address: email@example.com. (c) parallel resonance needs a low-resistance source for a sharp in¬crease in impedance RPM. Inductance affects the direct current flow (c) when one wave reaches its maxi¬mum value, the other will reach its minimum value (a) increases with the decrease of capacitance and decrease of resistance
In series resonant circuit, increasing inductance to its twice value and reducing capacitance to its half value
(c) square wave
Ans: c, 93.
The double energy transient occur in the, 12. (b) 0.1 s