What is the frequency of an alternator which has 2 poles and makes 3600 revolutions per minute? A) 3600 HZ B) 60 Hz C) 120 Hz D) None of these
Last Answer : What is the frequency of an alternator which has 2 poles and makes 3600 revolutions per minute? A) 3600 HZ B) 60 Hz C) 120 Hz D) None of these
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Apr 29, 2018
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anonymous

Last Answer : An alternator coupled to a hydraulic turbine runs at slow speed, as compared to others.
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105 views
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Mar 20, 2018
by
anonymous

State working principle of alternator. State the meaning self and separate excitation.
Last Answer : Working principle of alternator: When a conductor is moved in magnetic field or a magnetic field moved with respect to conductor, according to Faraday's law of electromagnetic induction, the conductor ... like battery or shaft-mounted exciter, then the excitation is said to be separate excitation.
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May 27, 2020
by
anonymous

Explain the construction of alternator with neat diagram.
Last Answer : Diagram: Construction of three phase alternator: Construction wise, an alternator generally consists of field poles placed on the rotating fixture of the machine i.e. rotor as shown in the ... of rotor used in construction of alternator, 1. Salient pole type. 2. Cylindrical rotor type.
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316 views
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Jul 30, 2019
by
anonymous

At which power factor alternator is said to be overexcited?
Last Answer : At leading power factor alternator is said to be overexcited.
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97 views
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Mar 18, 2018
by
anonymous

The power factor of an alternator depends on?
Last Answer : The power factor of an alternator depends on load.
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116 views
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Mar 18, 2018
by
anonymous

In an alternator at lagging power factor the generated voltage per phase as compared to that at unity power factor?
Last Answer : In an alternator, at lagging power factor the generated voltage per phase as compared to that at unity power factor must be more than terminal voltage.
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524 views
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Mar 18, 2018
by
anonymous

The magnitude of various voltage drops that occur in an alternator depends on?
Last Answer : The magnitude of various voltage drops that occur in an alternator depends on load current.
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594 views
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Mar 18, 2018
by
anonymous

In alternator where the voltage drop occurs?
Last Answer : In alternator voltage drop occurs in armature resistance, leakage reactance, and armature reactance.
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139 views
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Mar 18, 2018
by
anonymous

The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque (1) Decreases (2) Increases (3) Remains constant (4) None of the above
Last Answer : The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque Increases
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235 views
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May 1, 2018
by
anonymous

Draw and explain pneumatic proportional controller.
Last Answer : Explanation : Basic : Proportional control is one in which the process input is change in direct proportion to the error(t) controls the output so that the manipulated variable and the error has proportional relation. ... the MV and SP reference value called as error Given as : Error = SP - MV
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Jul 21, 2019
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anonymous
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Power in the wind is proportional to
Last Answer : Power in the wind is proportional to (Wind velocity)3
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May 1, 2018
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anonymous

109 views
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Mar 22, 2018
by
anonymous

Last Answer : The friction at the track is proportional to speed.
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148 views
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Mar 22, 2018
by
anonymous

What is an alternator?
Last Answer : Ans. Alternator is a machine which converts mechanical energy into electrical energy
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Define armature reaction in an alternator. Explain the effect of armature reaction at various P.F. of loads of alternator.
Last Answer : Armature Reaction: The effect of armature flux on main flux is called as armature reaction. Armature Reaction at Various Power Factors: When armature is loaded, the armature flux modifies ... lagging p.f. For capacitive loads the effect of flux is partly distorting and partly strengthening.
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May 7, 2020
by
anonymous

Draw equivalent circuit of alternator.
Last Answer : Equivalent circuit of alternator
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259 views
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May 6, 2020
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anonymous
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Alternator
Last Answer : .embed-container { position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; } .embed-container iframe, .embed-container object, .embed-container embed { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }
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Jul 6, 2019
by
anonymous

While keeping the excitation constant, if the steam supply of an alternator running in parallel with another identical alternator is increased, then (A) It would over-run the other alternator (B) Its rotor ... (C) Its portion of share in load will increase (D) Its power factor would be decreased.
Last Answer : While keeping the excitation constant, if the steam supply of an alternator running in parallel with another identical alternator is increased, then Its portion of share in load will increase
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430 views
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Apr 28, 2018
by
anonymous

The fractional-pitch used for eliminating 7th harmonic from the emf wave of an alternator is (A) 2/3 (B) 5/6 (C) 7/8 (D) 6/7
Last Answer : The fractional-pitch used for eliminating 7th harmonic from the emf wave of an alternator is 6/7
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495 views
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Apr 28, 2018
by
anonymous

What causes diodes to fail in alternator?
Last Answer : alternator
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77 views
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Mar 15, 2018
by
anonymous

Salient pole rotor is use for which speed?
Last Answer : Salient pole rotor is use for low and medium speed prime movers.
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Mar 18, 2018
by
anonymous

Which rotor is use for high speed in turbo alternators?
Last Answer : Non-salient pole rotor is used for high speed in turbo alternators.
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81 views
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Mar 18, 2018
by
anonymous

Consider the sinusoidal voltage waveforms, v1(t) and v2(t), as shown (i) State the frequency and amplitude for both the voltage waveforms. (ii) Calculate the rms value of v1(t) and v2(t), ... time domain. (vii) Calculate the instantaneous value of v2(t) at t = 38 ms.
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May 19, 2020
by
anonymous

Sinusoids find amplitude, period, frequency, voltage (Problem 1)
Last Answer : Sinusoids find amplitude, period, frequency, voltage (Problem 1)
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Mar 29, 2020
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anonymous

Principal of digital frequency meter.
Last Answer : The basic block diagram of basic digital frequency meter (DFM) is shown in above figure. The signal whose frequency we have to be measured is first to be amplified through amplifier. The output of amplifier ... = Number of counts. t = Time interval between start and stop condition of the gate.
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2 answers
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Aug 21, 2019
by
anonymous

Define the following terms: 1) Virtual height 2) Actual height 3) Critical frequency. 4) Maximum usable frequency.
Last Answer : 1) Virtual height:- The incident and refracted rays follow paths that are exactly the same as they have been if reflection had taken place from a surface located at a greater height, called ... angle of incidence is other than the normal is known as maximum unstable frequency. MUF= fc secθ
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Aug 4, 2019
by
anonymous

Draw the diagram and explain the working of ferrodynamic type frequency meter.
Last Answer : Ferrodynamic type frequency meter: (Electrical resonance type frequency meter): It consists of a fixed coil. The supply whose frequency is to be measured is connected across it. This coil ... so selected that the moving coil takes up a convenient position when frequency is of normal value.
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6.4k views
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Sep 6, 2018
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anonymous

List the different types of frequency meters.
Last Answer : Different types of frequency meters 1. Reed type [Mechanical type] 2. Ferro-dynamic type [Resonances type] 3. Weston type 4. Ratio-meter type 5. Saturable core type 6. Digital type
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82 views
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Sep 6, 2018
by
anonymous

Explain working of Weston type frequency meter.
Last Answer : Weston Type Frequency Meter: There are two fixed coils marked as A and B. Each coil divided into two equal parts and are fixed such that their magnetic axis are perpendicular to each ... leading to deflections in either direction depending on the currents there in, due to changed impedances.
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Sep 5, 2018
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anonymous

State the application of phase sequence indicator; clip on ammeter, frequency meter & P.F. meter.
Last Answer : Phase Sequence Indicator: 1. For finding correct phase sequence of supply 2. For obtaining exact instant of parallel operation of alternators. 3. For obtaining reversal of rotation ... 4. In electroplating industries 5. In various processes industries for measuring power factor
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146 views
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Sep 5, 2018
by
anonymous

List two types of oscillator, which generates frequency in RF range.
Last Answer : Types of Oscillators generating frequencies in RF range: i) Hartley Oscillator ii) Colpitt’s Oscillator iii) Clapp Oscillator
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83 views
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Sep 5, 2018
by
anonymous

State the need of multistage amplifier. Draw frequency response of R-C coupled amplifier.
Last Answer : The need of multistage amplifier The voltage (or power) gain, obtained from a single stage small signal amplifier, is limited. Therefore, it is not sufficient for all practical applications. Therefore, in ... to use a MULTISTAGE AMPLIFIER . Frequency response of R-C coupled amplifier.
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Sep 5, 2018
by
anonymous

Classify the transformers based on the construction, frequency and power.
Last Answer : Classification of Transformer Based On: i) Construction: Shell type, Core type, Berry type ii) Change in voltage level: Step-Up, Step-Down, iii) Number of phases: Single phase, Three phase iv) ... Control vi) Cooling: Self-cooled, Air-cooled, Forced-air cooled, Oil-cooled, Forced-oil cooled.
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Aug 30, 2018
by
anonymous

Define: 1) frequency, 2) cycle, 3) time period, 4) amplitude
Last Answer : 1) frequency: The total number of cycles completed in one second is called frequency. Its unit is cycles per second or Hertz (Hz). Its formula is f = 1/ T, where T is time period. ... is second per cycle. 4) amplitude: the maximum instantaneous value of sine wave is called as amplitude.
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384 views
2 answers
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Aug 8, 2018
by
anonymous
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A pulse radar has a pulse repetition frequency (PRF) of 3 KHz. If the radar is emitting at 10 GHz, what is the maximum unambiguous range for this radar? A) 5 Km B) 5 m C) 50 Km D) 15 m
Last Answer : A pulse radar has a pulse repetition frequency (PRF) of 3 KHz. If the radar is emitting at 10 GHz, what is the maximum unambiguous range for this radar? A) 5 Km B) 5 m C) 50 Km D) 15 m
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1 answer
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Jun 18, 2018
by
anonymous

A pulse compression radar transmits an encoded pulse having a frequency chirp from 990 MHz to 1010 MHz centred around 1 GHz. The range resolution capability of this radar is A) 7.5 m B) 7.5 Km C) 75 m D) 750 m
Last Answer : A pulse compression radar transmits an encoded pulse having a frequency chirp from 990 MHz to 1010 MHz centred around 1 GHz. The range resolution capability of this radar is 7.5 m
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223 views
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Jun 18, 2018
by
anonymous

The clock frequency of an 8085 microprocessor based system is 3 MHz. What should be the minimum pulse width of the INTR signal so that it is recognized successfully? A) 5.6 µs B) 5.7 µs C) 5.8 µs D) 5.9 µs
Last Answer : The clock frequency of an 8085 microprocessor based system is 3 MHz. What should be the minimum pulse width of the INTR signal so that it is recognized successfully? A) 5.6 µs B) 5.7 µs C) 5.8 µs D) 5.9 µs
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1.5k views
1 answer
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Jun 18, 2018
by
anonymous

What is the frequency range of VHF electromagnetic waves? A) 30-300 kHz B) 30-3000 kHz C) 30-300 MHz D) 30-3000 MHz
Last Answer : What is the frequency range of VHF electromagnetic waves? A) 30-300 kHz B) 30-3000 kHz C) 30-300 MHz D) 30-3000 MHz
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415 views
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Jun 18, 2018
by
anonymous

The SCR would be turned OFF by voltage reversal of applied anode-cathode ac supply frequency of A) 10 kHz B) 10 Hz C) 5 kHz D) 5 Hz
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187 views
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Jun 18, 2018
by
anonymous

Which of the following thyristors can be used for high frequency of operation? A) TRIAC B) DIAC C) SCR D) GTO
Last Answer : Which of the following thyristors can be used for high frequency of operation? A) TRIAC B) DIAC C) SCR D) GTO
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109 views
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Jun 18, 2018
by
anonymous

In a series R-C circuit, with the increase in frequency, current (A) Reduces (B) Increases (C) Does not change (D) Becomes zero
Last Answer : In a series R-C circuit, with the increase in frequency, current Increases
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111 views
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May 8, 2018
by
anonymous

A series R-L-C Circuit has a resonant frequency of 1000 Hz. If the values of R, L and C are doubled, the new resonant frequency is
Last Answer : A series R-L-C Circuit has a resonant frequency of 1000 Hz. If the values of R, L and C are doubled, the new resonant frequency is 500 Hz
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453 views
1 answer
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May 8, 2018
by
anonymous

What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to a 500 Hz (frequency) source of the same voltage: (A) Eddy Current and Hysteresis losses will be ... Current will be too much high (C) Transformer may start to smoke and burn (D) No effect
Last Answer : What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to a 500 Hz (frequency) source of the same voltage: (A) Eddy Current and Hysteresis losses will be ... will be too much high (C) Transformer may start to smoke and burn (D) No effect
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795 views
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May 8, 2018
by
anonymous
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For measurement of radio frequency ac signals __________ type meter is used
Last Answer : For measurement of radio frequency ac signals thermo-couple type meter is used
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182 views
1 answer
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Apr 30, 2018
by
anonymous

In a series RLC high Q circuit, the current peaks at a frequency (1) equal to the resonant frequency (2) greater than the resonant frequency (3) less than the resonant frequency (4) equal to half the resonant frequency
Last Answer : In a series RLC high Q circuit, the current peaks at a frequency equal to the resonant frequency
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1.4k views
1 answer
asked
Apr 29, 2018
by
anonymous

In a self-controlled synchronous motor fed from a variable frequency inverter (1) the rotor poles invariably have damper windings (2) there are stability problems (3) the speed of the rotor decides stator frequency (4) the frequency of the stator decides the rotor speed
Last Answer : 2
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637 views
2 answers
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Apr 29, 2018
by
anonymous

For a 500 Hz frequency excitation, a 50 km long power line will be modeled as
Last Answer : For a 500 Hz frequency excitation, a 50 km long power line will be modeled as long line
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2.8k views
1 answer
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Apr 29, 2018
by
anonymous
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What happens to the voltage in the secondary when the frequency of the supply in the primary is decreased? A) It increases B) It decreases C) It remains the same D) Cannot say unless the actual percentage increase in the frequency is known
Last Answer : What happens to the voltage in the secondary when the frequency of the supply in the primary is decreased? A) It increases B) It decreases C) It remains the same D) Cannot say unless the actual percentage increase in the frequency is known
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119 views
1 answer
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Apr 29, 2018
by
anonymous

The device which allows reverse power flow and withstands highest switch frequency is (A) GTO (B) MOSFET (C) IGBT (D) Inverter grade SCR
Last Answer : The device which allows reverse power flow and withstands highest switch frequency is MOSFET
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89 views
1 answer
asked
Apr 28, 2018
by
anonymous
