State any four characteristics of core type transformer.
Last Answer : Characteristics of core type transformer: i) It has one window. ii) It has one magnetic circuit. iii) Core surrounds the winding. iv) Average length of core is more. v) Area of cross ... Better cooling for winding. vii) Mechnical strength is comparatively less. viii) Repair and maintenance is easy.
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132 views
1 answer
asked
Jul 27, 2019
by
anonymous
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Last Answer : Material used for construction of transformer core is usually silicon steel.
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241 views
1 answer
asked
Mar 19, 2018
by
anonymous

When secondary of a current transformer is open-circuited its iron core will be?
Last Answer : When secondary of a current transformer is open-circuited its iron core will be hot because of heavy iron losses taking place in it due to high flux density.
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165 views
1 answer
asked
Mar 19, 2018
by
anonymous
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Reduction in core losses and increase in permeability are obtained with transformer employing?
Last Answer : Reduction in core losses and increase in permeability are obtained with transformer employing core built-up of laminations of cold rolled grain oriented steel.
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615 views
1 answer
asked
Mar 19, 2018
by
anonymous
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A 40 kVA transformer has a core loss of 400 W and a full load copper loss of 800 W. The proportion of full load at maximum efficiency is
Last Answer : A 40 kVA transformer has a core loss of 400 W and a full load copper loss of 800 W. The proportion of full load at maximum efficiency is 0.707
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776 views
1 answer
asked
May 8, 2018
by
anonymous

The core construction is like spokes of a wheel in following transformer: (A) Berry Type Transformer (B) Core Type Transformer (C) Shell Type Transformer (D) None of the above
Last Answer : The core construction is like spokes of a wheel in following transformer: Berry Type Transformer
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133 views
1 answer
asked
May 8, 2018
by
anonymous

The desirable properties of transformer core material are (1) low permeability and low hysteresis loss. (2) high permeability and high hysteresis loss. (3) high permeability and low hysteresis loss. (4) low permeability and hysteresis loss.
Last Answer : The desirable properties of transformer core material are high permeability and low hysteresis loss.
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235 views
1 answer
asked
May 1, 2018
by
anonymous

The main purpose of using core in a transformer is to (A) decrease iron losses (B) eliminate magnetic hysteresis (C) reduce reluctance of the common magnetic circuit (D) prevent eddy current loss
Last Answer : Reduce Relucatnce of the common magnetic circuit.
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2.0k views
2 answers
asked
Apr 28, 2018
by
anonymous

Why does the core of a transformer need to be laminated?
Last Answer : Transformer cores are laminated to reduce eddy current loss.
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122 views
1 answer
asked
Mar 14, 2018
by
anonymous
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Last Answer : Transformer core is laminated to reduce Eddy current losses.
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112 views
1 answer
asked
Sep 30, 2017
by
anonymous

Last Answer : The purpose of providing an iron core in a transformer is to decrease the reluctance of the magnetic path.
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205 views
1 answer
asked
Mar 19, 2018
by
anonymous

Last Answer : The purpose of providing iron core in a step-up transformer is to decrease the magnitude of magnetizing current.
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546 views
1 answer
asked
Mar 19, 2018
by
anonymous

Last Answer : The core used in high frequency transformer is usually air core .
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214 views
1 answer
asked
Mar 19, 2018
by
anonymous

State the material used for making (1) Magnetic Core (2) Fuse element
Last Answer : The material used for making of: (1) Magnetic Core : Iron, cobalt, Nickel, CRGO, HRGO , silicon steel (2) Fuse Element: Tin- lead wire, Tinned copper wire
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210 views
1 answer
asked
May 7, 2020
by
anonymous

Core type transformers are popular in___________. (A) High voltage applications (B) Low voltage applications (C) All of the above (D) None of the above
Last Answer : Core type transformers are popular in High voltage applications
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96 views
1 answer
asked
May 8, 2018
by
anonymous

A single core lead sheathed cable with two dielectrics of permittivity 4 and 3, respectively, are subjected to same maximum stress. If the conductor diameter is 1.5 cm, the outer diameter of the first dielectric is (A) 1.125 cm (B) 1.5 cm (C ) 2 cm (D) 8 cm
Last Answer : A single core lead sheathed cable with two dielectrics of permittivity 4 and 3, respectively, are subjected to same maximum stress. If the conductor diameter is 1.5 cm, the outer diameter of the first dielectric is 2 cm
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172 views
1 answer
asked
Apr 28, 2018
by
anonymous

A single core cable is designed to work for a single phase system with a peak voltage of 220 kV. The maximum permissible stress in the dielectric is not to exceed 20 kV/mm. For economical size, the overall core diameter of the cable is (A) 28.2 mm (B) 26.4 mm (C) 24.4 mm (D) 22.0 mm
Last Answer : A single core cable is designed to work for a single phase system with a peak voltage of 220 kV. The maximum permissible stress in the dielectric is not to exceed 20 kV/mm. For economical size, the overall core diameter of the cable is 22.0 mm
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757 views
1 answer
asked
Apr 28, 2018
by
anonymous

A ferrite core has less eddy current loss than an iron core because?
Last Answer : A ferrite core has less eddy current loss than an iron core because ferrites have high hysteresis.
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382 views
1 answer
asked
Mar 25, 2018
by
anonymous

Last Answer : The armature core of a D.C. generator is usually made of silicon steel.
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153 views
1 answer
asked
Mar 20, 2018
by
anonymous
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Last Answer : When a conductor carries more current on the surface as compared to core, it is due to skin effect.
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172 views
1 answer
asked
Mar 20, 2018
by
anonymous

In DC generators lamination core are generally made of?
Last Answer : In DC generators lamination core are generally made of silicon steel.
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257 views
1 answer
asked
Mar 3, 2018
by
anonymous

Does size matter?
Last Answer : In sports, sure it can matter. But you have to be athletic too.
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1 view
1 answer
asked
Mar 5
by
anonymous
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Is size 14 fat?
Last Answer : Not necessarily.
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1 view
1 answer
asked
Feb 14
by
anonymous

How to Size a Helmet
Last Answer : How to Size a Helmet A helmet that fits you right will save you a lot of headaches in the future. Nothing ruins a good run in your motorcycle, race car or anything similar than an ill-fitting ... go. Having a loose chinstrap can cause your helmet to fly away, exposing you and others to danger.
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8 views
1 answer
asked
May 11, 2021
by
anonymous

How to Find Your Hat Size ?
Last Answer : How to Find Your Hat Size Hats are great fashion accessories, but if you insist on wearing ones that don't fit you, then it's not quite as great. Here's how to ensure that every hat you purchase ... a brand with sizes that fit you, you now have a source of fine-fitting hats whenever you need them.
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4 views
1 answer
asked
May 8, 2021
by
anonymous

Which bed size is right for you?
Last Answer : Which bed size is right for you? At first glance, the bed seems to be a simple and unpretentious device, but its selection is a rather responsible event. First of all, this concerns issues ... lengthen the frame, which affects the consumption of materials and, accordingly, the cost of the product.
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7 views
1 answer
asked
Mar 27, 2021
by
anonymous

State two factors deciding size of conduit.
Last Answer : Following factors deciding size of conduit: 1) Types of wiring method 2) No. of wires carried out through conduit 3) Size of wires required for sub circuits which is carried out through conduit 4) Future expansion.
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472 views
1 answer
asked
Sep 22, 2018
by
anonymous

What is the choice of size and number of generator units in interconnected power system?
Last Answer : Choice of Size and Number of Generating Units: 1. The size/rating and number of generating units in such way that they approximately match with the load curve as closely as possible. 2. In ... , if power plant is connected to grid system then generating unit of higher capacity can be installed.
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113 views
1 answer
asked
Sep 7, 2018
by
anonymous

Calculate the size of memory address space for a 16 bit data and 20 bit address bus. A) 1 MB B) 2 MB C) 3 MB D) 4 MB
Last Answer : Calculate the size of memory address space for a 16 bit data and 20 bit address bus. A) 1 MB B) 2 MB C) 3 MB D) 4 MB
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202 views
1 answer
asked
Jun 18, 2018
by
anonymous

What is the size of memory which can be accessed by direct accessing in 8085 microprocessor? A) 64 kB B) 4 kB C) 128 kB D) 128 MB
Last Answer : What is the size of memory which can be accessed by direct accessing in 8085 microprocessor? A) 64 kB B) 4 kB C) 128 kB D) 128 MB
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149 views
1 answer
asked
Jun 18, 2018
by
anonymous

For a 15-bus power system with 3 voltage controlled buses, the size of Jacobian matrix is
Last Answer : For a 15-bus power system with 3 voltage controlled buses, the size of Jacobian matrix is 25 x 25
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2.2k views
1 answer
asked
Apr 27, 2018
by
anonymous

Last Answer : The size of a synchronous motor decreases with the increase in flux density.
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196 views
1 answer
asked
Mar 20, 2018
by
anonymous

Explain the effect of Harmonics on the Transformer.
Last Answer : Effect of Harmonics on the Transformer: 1. Core loss: Harmonic voltage increases the hysteresis and eddy current losses in the lamination. The amount of the core loss depends on ... small core vibrations. 5. Saturation problem: Sometimes additional harmonic voltage causes core saturation.
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130 views
1 answer
asked
May 22, 2020
by
anonymous

List two special feature of welding transformer.
Last Answer : Special features of welding transformer: i) It is a step down transformer that reduces the source voltage to a voltage desired according to the demands of the welding process. ii) Having large primary turns and less ... V ii) Secondary voltage - 40 to 60 V iii) Secondary current - 200 to 600 A
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154 views
1 answer
asked
May 22, 2020
by
anonymous

State two applications of isolation transformer
Last Answer : Applications of isolation transformer: i) Isolates the load equipment from supply ground: ii) Reduction of voltage spikes iii) It acts as a decoupling device. iv) Protects loads from harmonic distortion.
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54 views
1 answer
asked
May 22, 2020
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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279 views
1 answer
asked
May 22, 2020
by
anonymous

Equivalent circuit of transformer
Last Answer : Equivalent Circuit Diagram of Transformer Referred to Primary: V1 -Primary Input voltage I1 - Input Current I0- Exciting current/ No load current Im- Magnetizing component ... equivalent of secondary terminal voltage ZL- Load impedance ZL ′- Primary equivalent of load impedance
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381 views
2 answers
asked
May 17, 2020
by
anonymous

Single phase transformer
Last Answer : Single phase Transformer Transformer
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261 views
1 answer
asked
May 16, 2020
by
anonymous

What is the use of transformer?
Last Answer : The use of transformer is to do lower or raise the voltage or currents in an electrical circuit. That's quite so simple.
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160 views
1 answer
asked
May 15, 2020
by
anonymous

Write about transformer on DC.
Last Answer : Transformer on DC : Transformer cannot work on DC. Transformer works on electromagnetic induction principle. Electromagnetic induction principle means when flux linking with coil changes and EMF induced in it ... winding insulation will burn. https://youtu.be/TVp_0fIfxqY
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248 views
1 answer
asked
May 10, 2020
by
anonymous

Even at no-load, a transformer draws current from the mains. Why?
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115 views
0 answers
asked
Apr 28, 2020
by
anonymous
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State and justify which of the following two transformers is better: Transformer A = 4% voltage regulation Transformer B = 6% voltage regulation
Last Answer : Transformer A with 4% voltage regulation is better. Justification: Voltage regulation refers to the percentage change in secondary voltage when load is changed from no-load to full-load with primary voltage ... 4% voltage regulation, which is less as compared to 6% of transformer B, it is better.
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181 views
1 answer
asked
Jul 27, 2019
by
anonymous

Explain construction and working of single phase Auto transformer.
Last Answer : Construction of single phase auto transformer: (i) It has only one winding wound on a laminated circular magnetic core. (ii) The core is made of silicon steel stampings. (iii) The two terminals of the ... help of handle. 5) The same transformer can be used as step-up or step down auto-transformer
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347 views
1 answer
asked
Jul 26, 2019
by
anonymous

Last Answer : No-load current in a transformer lags behind the voltage by about 75°.
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90 views
1 answer
asked
Mar 19, 2018
by
anonymous

Last Answer : In the transformer low voltage winding has got more cross-sectional area.
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256 views
1 answer
asked
Mar 19, 2018
by
anonymous
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Last Answer : A transformer cannot raise or lower the voltage of a D.C. supply because Faraday's laws of electromagnetic induction are not valid since the rate of change of flux is zero.
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351 views
1 answer
asked
Mar 19, 2018
by
anonymous

Last Answer : Primary winding of a transformer could either be a low voltage or high voltage winding.
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86 views
1 answer
asked
Mar 19, 2018
by
anonymous

Last Answer : High voltage winding in a transformer has more number of turns.
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363 views
1 answer
asked
Mar 19, 2018
by
anonymous

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

Last Answer : The no load current in a transformer lags behind the applied voltage by an angle of about 75°.
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188 views
1 answer
asked
Mar 19, 2018
by
anonymous
