Last Answer : An ideal transformer will have maximum efficiency at a load such that copper loss equal to iron loss.
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208 views
1 answer
asked
Mar 19, 2018
by
anonymous

For a transformer, operating at constant load current, maximum efficiency will occur at?
Last Answer : For a transformer, operating at constant load current, maximum efficiency will occur at unity power factor.
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125 views
1 answer
asked
Mar 19, 2018
by
anonymous

Last Answer : D.C. generators are normally designed for maximum efficiency around full-load.
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102 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The condition for maximum efficiency for a D.C. generator is variable losses equal to constant losses.
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240 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : Generators for peak load plants are usually designed for maximum efficiency at 50 to 75 percent full load.
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142 views
1 answer
asked
Mar 20, 2018
by
anonymous
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Transformer efficiency
Last Answer : Transformer efficiency
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78 views
1 answer
asked
Jun 11, 2019
by
anonymous

A transformer operates 24 hours day at full -load. It's full -load efficiency is : (A) equal all day efficiency (B) more than all -day efficiency (C) less than all -day efficiency (D) equal to maximum efficiency
Last Answer : A transformer operates 24 hours day at full -load. It's full -load efficiency is : equal all day efficiency
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272 views
1 answer
asked
Apr 30, 2018
by
anonymous

Last Answer : The efficiency of transformer is Greater than electrical Machine because there is no rotational losses in transformer and there is no air gap losses in transformer so losses is less in transformer compare to electrical machine so efficiency is higher in case of transformer.
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136 views
3 answers
asked
Oct 5, 2017
by
anonymous

If a transformer is continuously operated the maximum temperature rise will occur in?
Last Answer : If a transformer is continuously operated the maximum temperature rise will occur in windings.
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81 views
1 answer
asked
Mar 19, 2018
by
anonymous

The maximum load that a power transformer can carry is limited by its?
Last Answer : The maximum load that a power transformer can carry is limited by its voltage ratio.
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133 views
1 answer
asked
Mar 19, 2018
by
anonymous

State why a transformer always have an efficiency of more than 90%.
Last Answer : As transformer is static device with no moving parts, the losses due to friction & windage are completely absent. Hence transformer has efficiency of more than 90%.
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366 views
1 answer
asked
May 22, 2020
by
anonymous

Last Answer : The efficiency of a power transformer is of the order of 98 percent.
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105 views
1 answer
asked
Mar 19, 2018
by
anonymous

The efficiency of a transformer, under heavy loads, is comparatively low because?
Last Answer : The efficiency of a transformer, under heavy loads, is comparatively low because copper loss becomes high in proportion to the output.
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115 views
1 answer
asked
Mar 19, 2018
by
anonymous

Define : i) Maximum Value ii) RMS Value of ac supply
Last Answer : i) Maximum Value :- The maximum or peak value attained by an alternating quantity during positive or negative half cycle, is called maximum value or peak value. ii) RMS Value of ac ... as produced by the alternating current when flowing through the same resistance and for the same time.
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87 views
1 answer
asked
Aug 17, 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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84 views
1 answer
asked
Aug 4, 2019
by
anonymous

Maximum Power Transfer Theorem 1
Last Answer : Maximum Power Transfer Theorem 1
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94 views
1 answer
asked
May 22, 2019
by
anonymous

State maximum power transfer theorem for DC circuit.
Last Answer : Maximum power transfer theorem for DC circuit: The maximum power transfer theorem states that the source or a network transfers maximum power to load only when the load resistance is equal ... removed (disconnected) ii) All internal independent sources are replaced by their internal resistances.
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111 views
1 answer
asked
Sep 6, 2018
by
anonymous

An independent voltage source in series with an impedance ZS=R+jXS delivers a maximum average power to a load impedance ZL when A) ZL = R B) ZL = jXS C) ZL = R-jXS D) ZL = R+jXS
Last Answer : An independent voltage source in series with an impedance ZS=R+jXS delivers a maximum average power to a load impedance ZL when ZL = R-jXS
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4.0k views
1 answer
asked
Jun 18, 2018
by
anonymous

method for improving string efficiency
Last Answer : The Methods of Improving String Efficiency:- 1) By reducing value of ‘m’ or (‘k’) by using longer cross arm. 2) By Making of ‘m’ or (‘k’) equal to zero 3) By grading Insulator. 4) By Using guard ring.
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118 views
1 answer
asked
Aug 25, 2019
by
anonymous

"Efficiency of thermal power station is low". — Justify.
Last Answer : Justification: Efficiency of thermal power station is low":- Overall efficiency of T.P.P depends upon efficiency of boiler, turbine and alternator. The heat produced due to combustion of coal ... losses in thermal power plant is 71%, So efficiency of thermal power plant is less about 29%
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106 views
1 answer
asked
Aug 2, 2019
by
anonymous

A certain power MOSFET has a maximum junction temperature specification of 1500o C, a junction-to-case thermal resistance of 1.00 C/W, and a junction-to ambient thermal resistance of 600 C/W. If the ambient temperature is 300o C ... the device will be A) 1.52 W B) 1.72 W C) 1.92W D) 2.00 W
Last Answer : A certain power MOSFET has a maximum junction temperature specification of 1500o C, a junction-to-case thermal resistance of 1.00 C/W, and a junction-to ambient thermal resistance of ... 300o C, then the maximum allowable power dissipation in the device will be 2.00 W
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149 views
1 answer
asked
Jun 18, 2018
by
anonymous

The maximum reluctance power of a salient-pole synchronous motor having direct-axis reactance, 1.0 pu and quadrature-axis reactance, 0.5 pu, and input voltage, 1.0 pu is (A) 0.25 pu (B) 0.5 pu (C) 1.0 pu (D) 1.5 pu
Last Answer : The maximum reluctance power of a salient-pole synchronous motor having direct-axis reactance, 1.0 pu and quadrature-axis reactance, 0.5 pu, and input voltage, 1.0 pu is 0.5 pu
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100 views
1 answer
asked
Apr 28, 2018
by
anonymous

The maximum torque of d.c. motors is limited by?
Last Answer : The maximum torque of d.c. motors is limited by commutation.
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857 views
1 answer
asked
Mar 26, 2018
by
anonymous

For maximum transfer of power, internal resistance of the source should be?
Last Answer : For maximum transfer of power, internal resistance of the source should be equal to load resistance.
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374 views
1 answer
asked
Mar 25, 2018
by
anonymous

"Maximum power output is obtained from a network when the load resistance is equal to the output resistance of the network as seen from the terminals of the load". The above statement is associated with?
Last Answer : "Maximum power output is obtained from a network when the load resistance is equal to the output resistance of the network as seen from the terminals of the load". The above statement is associated with Maximum power transfer theorem.
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400 views
1 answer
asked
Mar 25, 2018
by
anonymous

Last Answer : Series motor has got maximum self relieving property.
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193 views
1 answer
asked
Mar 20, 2018
by
anonymous
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Last Answer : (b) Clostridium butylicum Lipase Removal of oil stains
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109 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is 0.5.
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329 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : In a D.C. shunt motor, under the conditions of maximum power, the current in the armature will be more than full-load current.
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376 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : In repulsion motor, maximum torque is developed when brush axis is at 45° electrical to the field axis.
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117 views
1 answer
asked
Mar 20, 2018
by
anonymous

The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as?
Last Answer : The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as pull-in torque.
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307 views
1 answer
asked
Mar 20, 2018
by
anonymous

The maximum torque which a synchronous motor will develop at rest for any angular position of the rotor, at rated stator supply voltage and frequency, is known as?
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106 views
0 answers
asked
Mar 20, 2018
by
anonymous

Last Answer : In a power plant if the maximum demand on the plant is equal to the plant capacity, then plant reserve capacity will be zero.
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279 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : Maximum demand on a power plant is the greatest of all "short time interval averaged" demand during a period.
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99 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : More than 100%
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163 views
2 answers
asked
Mar 20, 2018
by
anonymous

What is the maximum value of power factor?
Last Answer : 1 is the maximum value of power factor.
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122 views
1 answer
asked
Mar 19, 2018
by
anonymous
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In which fault the maximum short circuit current occurs?
Last Answer : In three phase bolted fault the maximum short circuit occurs.
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131 views
1 answer
asked
Mar 19, 2018
by
anonymous

What is the maximum value of torque angle in synchronous motor?
Last Answer : The maximum value of torque angle in synchronous motor is 90 degrees electrical.
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1.5k views
1 answer
asked
Mar 18, 2018
by
anonymous

The synchronous motor will develop maximum power when the load angle is?
Last Answer : The synchronous motor will develop maximum power when the load angle is 900.
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234 views
1 answer
asked
Mar 18, 2018
by
anonymous

What is the maximum number of circuit breakers in a panel?
Last Answer : It depends on that which type of panel is this.
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112 views
1 answer
asked
Mar 10, 2018
by
anonymous

At what power maximum efficiency of power transformer and distribution transformer is designed
Last Answer : Maximum efficiency of the transformer is attained at certain load factor (α) when core losses of transformer is equal to the copper losses. PCore loss = α ^2 X PCopper loss From the ... the day. Hence distribution transformers are designed to have maximum efficiency at 50% of the rated full load
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5 views
1 answer

What is the condition for maximum efficiency of transformer?
Last Answer : When Iron losses is equal to copper losses.
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5 views
1 answer

42 The efficiency of a transformer will be maximum when A. copper losses = hysteresis losses B. Hysteresis losses = eddy current losses C. Eddy current losses = copper losses D. Copper losses = iron losses
Last Answer : D. Copper losses = iron losses
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22 views
1 answer

Last Answer : The maximum efficiency of a distribution transformer is at 50% full load.
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143 views
1 answer
asked
Mar 19, 2018
by
anonymous

SEER: Seasonal Energy Efficiency Ratio (SEER)
Last Answer : SEER: Seasonal Energy Efficiency Ratio (SEER), is most commonly used to measure the efficiency of a central air conditioner. The higher the SEER, the more efficient the system OR It is the ... the ratio of total capacity to the total KW energy usage at specific humidity and temperature condition.
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27 views
1 answer
asked
Jan 2, 2021
by
anonymous
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Compare the salient features of LED and CFL based on: i] Lamp Efficiency ii] Life span
Last Answer : Parameter LED CFL Lamp Efficiency High (more than 70 lumen per watt) Comparatively less (50-60 lumen per watt) Life span (in working hours) 10000 3000
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96 views
1 answer
asked
May 3, 2020
by
anonymous

Define PIV, TUF, ripple factor, efficiency of rectifier.
Last Answer : PIV: Peak Inverse Voltage (PIV) is defined as the maximum negative voltage which appears across non-conducting reverse biased diode. TUF : Transformer Utilization Factor (TUF) is defined as the ratio of DC output ... Efficiency of rectifier: η = DC output power/ AC input power = PLdc / Pac
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839 views
2 answers
asked
May 2, 2020
by
anonymous
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What is the efficiency of Class-B amplifier? A) 68.50% B) 78.50% C) 88.50% D) 98.50%
Last Answer : What is the efficiency of Class-B amplifier? A) 68.50% B) 78.50% C) 88.50% D) 98.50%
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94 views
1 answer
asked
Jun 18, 2018
by
anonymous

The overall efficiency of Thermal Power Plant is equal to _______________ . (A) Regenerative Cycle Efficiency (B) Renkine Cycle Efficiency (C) Carnot cycle efficiency (D) None of the above
Last Answer : The overall efficiency of Thermal Power Plant is equal to Regenerative Cycle Efficiency.
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460 views
1 answer
asked
May 8, 2018
by
anonymous

The rankine cycle efficiency of steam power plant is (1) 60-80% (3) 30-45% (2) 45-80% (4) 20-30%
Last Answer : The rankine cycle efficiency of steam power plant is 30-45%
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112 views
1 answer
asked
Apr 29, 2018
by
anonymous
