Last Answer : The material for commutator brushes is generally carbon.
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151 views
1 answer
asked
Mar 20, 2018
by
anonymous
State two applications of : (i) PVC paper (ii) Porcelain with type of class based on withstand temperature is insulating material.
Last Answer : (i) Application of PVC paper : 1. It is used in slot lining or motor winding insulation purpose 2. For Insulation of Transformer winding (ii) Application of Porcelain : 1. Mainly used for manufacturing ... on withstand temperature : * H' & C' Class of insulation i e. 180° and above 180°C
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306 views
1 answer
asked
May 7, 2020
by
anonymous
State gaseous and liquid insulating material.
Last Answer : i) Gaseous insulating material : 1. Air 2. Nitrogen 3. Hydrogen 4. SF6 ii) liquid insulating material: 1. Transformer oil 2. Capacitor oil 3. Cable oil 4. Pyranol 5. Savotal 6. Savol 7. Vegetable oil 8. Silicon liquids
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119 views
1 answer
asked
May 7, 2020
by
anonymous
Based on temperature withstanding ability, classify insulating material.
Last Answer : class Temperature withstanding ability in 0C Materials Y 90 Cotton, silk paper and similar organic materials neither impregnated nor immersed in any oil, rubber, PVC. A 105 ... rubber compounds C Above 180 Mica, ceramics, glass, Teflon, quartz, etc.
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86 views
1 answer
asked
Sep 4, 2018
by
anonymous
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List four examples of insulating material and explain any two.
Last Answer : Examples of insulating materials: i) Solid: Ceramic, Porcelain, Mica, Glass, Rubber, Resinous, Fibers ii) Liquid: Synthetic, Mineral etc. iii) Gaseous: Hydrogen, Air, ... and low hygroscopicity. Uses: Insulation in electric field, transformer stampings, armature, pole stampings
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105 views
1 answer
asked
Sep 4, 2018
by
anonymous
What is dielectric strength of an insulating material? What is its unit?
Last Answer : Dielectric Strength: The dielectric strength of an insulating material is the maximum voltage which the insulating medium can withstand without breakdown. Unit is volts per millimeter (V/mm), or kV/mm or kV/cm
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112 views
1 answer
asked
Sep 4, 2018
by
anonymous
What are insulating material?
Last Answer : Insulating material: Insulating material is that which offers very high resistance to the flow of current through it.
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64 views
1 answer
asked
Sep 4, 2018
by
anonymous
State the insulating materials used in motor. Write temperature class and withstand temperature ranges for them.
Last Answer : The insulating materials used in motor are as belows: 1. Cotton, 2. Silk, or paper, 3. Press board, 4. Resins 5. PVC 6. Cellulose-Fiber, 7. Enameled coating, etc ... Over 180° Mica, porcelain, ceramics, glass quartz, asbestos, treated glass fiber or treated asbestos. etc.
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173 views
1 answer
asked
May 7, 2020
by
anonymous
Last Answer : To avoid formation of grooves in the commutator of a D.C. machine the brushes of opposite polarity should track each other.
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3.0k views
1 answer
asked
Mar 21, 2018
by
anonymous
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Last Answer : The number of brushes in a commutator depends on amount of current to be collected.
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158 views
1 answer
asked
Mar 20, 2018
by
anonymous
Last Answer : In a commutator mica is harder than copper.
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62 views
1 answer
asked
Mar 20, 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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209 views
1 answer
asked
May 7, 2020
by
anonymous
State properties of conductor material used for overhead conductor.
Last Answer : Following are the properties of conductor material:- 1. High conductivity :- Material should have high conductivity 2. High mechanical strength:- Material should have sufficiently high mechanical strength ... available & less costly. 9. Scrap Value: - Material should have high scrap value.
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131 views
1 answer
asked
May 5, 2020
by
anonymous
Name the material used for :- (i) Moving coil (ii) Permanent magnet in PMMC instrument.
Last Answer : (i) Material used for Moving coil: Copper, Aluminum( some times) (ii) Permanent magnets are made of special alloys such as : Aluminum-Nickel-Cobalt (Alnicos) Strontium-Iron Neodymium-Iron-Boron Samarium-Cobalt.
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213 views
1 answer
asked
Sep 6, 2018
by
anonymous
State the material used for moving coil and former for PMMC instruments.
Last Answer : Material Used for Moving Coil and Former for PMMC Instruments: Material used for moving coil: Copper Material used for Former: Aluminium
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169 views
1 answer
asked
Sep 5, 2018
by
anonymous
The material used in liquid fuses is (1) SF6 (3) carbon tetra chloride (2) distilled water (4) transformer oil
Last Answer : The material used in liquid fuses is carbon tetra chloride
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392 views
1 answer
asked
Apr 30, 2018
by
anonymous
Last Answer : The material used for fuse must have low melting point and high specific resistance.
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162 views
1 answer
asked
Mar 20, 2018
by
anonymous
State the function of commutator in DC generator and name the material used for commutator.
Last Answer : Function of Commutator: Commutator converts AC induced in armature winding into DC for external load. Material: i) Commutator segments are made up of Copper. ii) Commutator segments are insulated from each other by Mica.
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256 views
1 answer
asked
Jul 27, 2019
by
anonymous
The function of a brush and commutator arrangement in a dc motor is to (1) produce unidirectional torque (2) produce unidirectional current in the armature (3) help in changing the direction of rotation of the armature (4) reduce sparking
Last Answer : The function of a brush and commutator arrangement in a dc motor is to produce unidirectional torque
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2.5k views
1 answer
asked
Apr 29, 2018
by
anonymous
Which of the following does not have a commutator? A) Dynamo B) Induction motor C) Universal motor D) None of these
Last Answer : Which of the following does not have a commutator? A) Dynamo B) Induction motor C) Universal motor D) None of these
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323 views
1 answer
asked
Apr 29, 2018
by
anonymous
Number of commutator bars for a 4-pole, 2-layer, DC lap winding with 24 slots and one conductor per layer is (A) 48 (B) 24 (C) 192 (D) 96
Last Answer : Number of commutator bars for a 4-pole, 2-layer, DC lap winding with 24 slots and one conductor per layer is 24
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2.0k views
1 answer
asked
Apr 28, 2018
by
anonymous
Last Answer : Sparking at the commutator of a D.C. motor may result in damage to commutator segments, damage to commutator insulation, increased power consumption.
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228 views
1 answer
asked
Mar 20, 2018
by
anonymous
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Last Answer : In a A.C. series motor armature coils are usually connected to commutator through resistance.
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161 views
1 answer
asked
Mar 20, 2018
by
anonymous
The insulating material used between the commutator segments is normally (a) graphite (b) paper (c) mica (d) insulating varnish
Last Answer : Ans: c
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19 views
1 answer
State the type of insulating materials under Class Y and Class B.
Last Answer : The type of insulating materials under Class Y : 1. Cotton 2. Silk 3. Paper 4. Rubber 5. PVC The type of insulating materials under Class B: 1. Backelite 2. Impregnated varnish 3. Mica 4. Fiber glass 5. Asbestos
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198 views
1 answer
asked
May 7, 2020
by
anonymous
State factors affecting the life of insulating materials.
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165 views
0 answers
asked
Apr 16, 2020
by
anonymous
Classification of insulating materials as per IS 8504- 1994
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345 views
0 answers
asked
Mar 19, 2020
by
anonymous
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State properties of insulating materials.
Last Answer : (i) Resistivity should be very high. (ii) It should be water resistant. (iii) It should not contain impurities. (iv) It should not be affected chemically and not corroded easily. (v) Its ... It should be mechanically strong (tensile strength should be more). (vii) It should not be porous.
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70 views
1 answer
asked
Aug 17, 2019
by
anonymous
Explain the mechanical properties of insulating materials.
Last Answer : i) Mechanical strength: Mechanical strength depends on temperature and humidity. a) Temperature: High temperature badly affects the mechanical strength of insulating material. While selecting material ... material should have property of easy moulding and machined into required shape and size.
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131 views
1 answer
asked
Sep 4, 2018
by
anonymous
The electric breakdown strength of insulating materials depends on (A) Nature of applied voltage (B) lmperfection of dielectric material (C) Pressure, temperature and humidity (D) All or these
Last Answer : The electric breakdown strength of insulating materials depends on (A) Nature of applied voltage (B) lmperfection of dielectric material (C) Pressure, temperature and humidity (D) All or these
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990 views
1 answer
asked
May 8, 2018
by
anonymous
Insulating materials have the function of?
Last Answer : Insulating materials have the function of preventing an open circuit between the voltage source and the load.
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474 views
1 answer
asked
Mar 25, 2018
by
anonymous
Last Answer : In case of D.C. machine winding, number of commutator segments is equal to number of armature coils.
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665 views
1 answer
asked
Mar 20, 2018
by
anonymous
Last Answer : The commutator segments are connected to the armature conductors by means of copper lugs.
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202 views
1 answer
asked
Mar 20, 2018
by
anonymous
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In addition to undercutting the mica, proper maintenance of a D.C. motor's commutator includes _______________. A. side-cutting the copper segments and insulating the slots B. coating the copper surface with light machine ... in an oven at a maximum of 95°C for not over 8 hours D. all of the above
Last Answer : Answer: A
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1 view
1 answer
Last Answer : The bearings used to support the rotor shafts are generally ball bearings.
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122 views
1 answer
asked
Mar 20, 2018
by
anonymous
Select insulating materials for following parts : (i) Insulation between heating element and base plate of electric iron. (ii) Insulation used over copper or aluminium conductor used for making coils. (iii) Transformer bushings. (iv) Insulation between transmission line and pole.
Last Answer : Parts Insulating Materials Insulation between heating element and base plate of electric iron. Mica Insulation used over copper or aluminium conductor used for making coils. ... Transformer bushings Porcelain Insulation between transmission line and pole. Porcelain
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199 views
1 answer
asked
May 7, 2020
by
anonymous
evergreen decking material
Last Answer : To do away from the problems associated with wood, such as high costs and decaying, alternative materials were introduced to the deck-builder market. Composite materials are the most popular among these ... driver can damage the groove edge of the board; aregular decking screw can be used instead.
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8 views
1 answer
boat decking material
Last Answer : You love staying in the upper deck of your boat while going on a cruise. It serves as your shelter from rain or direct sunlight, at the same time, it treats you to a great view of vast ... When the outer shell is surfaced with a weatherproof material, metal and wood as frames are not much different.
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11 views
1 answer
The Guide to Decking Material
Last Answer : Let's face it. The worst enemy of our home's interior are our kids and pets. All that's required to maintain the inside of our home is a little dusting, vacuuming and cleaning. For the ... of them come in various solid colors, which may work to your advantage when trying to cut painting costs.
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8 views
1 answer
wood decking material
Last Answer : Most builders choose wood as the main material for decks for several reasons. With proper treatment, wood is expected to last for years without needing any kind of repair. It is also ... for their expensive prices, all people should be encouraged to purchase natural wood decking materials only.
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7 views
1 answer
plastic decking material
Last Answer : Modern times call for modern solutions. If before, wood was the only material used to make decks, innovative alternatives are now available to avoid the problems associated with wood. Alternative materials ... with plastic decking materials; you don't need special tools to install them in your home.
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6 views
1 answer
decking material prices
Last Answer : Adding a deck to your house provides you with a new place to lounge around and host parties and improve the look of your home. Various materials may be used to build the deck. Naturally, prices also ... tend to have a trade-off in aesthetic quality, if not on the caliber of the very structure.
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5 views
1 answer
composite decking material
Last Answer : If you plan to add a new deck to your home, you're probably thinking about what material to use. Most people would look no further and will instantly get hardwood like Cedar and Redwood. ... against innovations, such a type of material is a very welcome development in the world of deck building.
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5 views
1 answer
best decking material
Last Answer : Today, homeowners are not only limited to choosing wood as the main material for their new deck. More modern materials such as composites and plastic are also available. The obvious question is ... decking material still depends on what you need and which among the factors above is your priority.
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6 views
1 answer
alternative decking material
Last Answer : Wood is the most popular decking material. It has the perfect fusion of beauty and firmness, so we need not ask why it is still the main choice of deck builders. Wood can also be ... your neighbors, consider using alternative decking materials, such as Veranda boards, when building your own deck.
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2 views
1 answer
Overalls. Which material is better?
Last Answer : Material is the most important factor to look out for when choosing workwear. Usually cotton, polyester or blended fabrics are chosen for the manufacture of workwear. Each option has ... , operating conditions and personal preferences. Work clothes should provide employees with comfort and safety.
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3 views
1 answer
asked
Mar 29, 2021
by
anonymous
What material should children's furniture be made of?
Last Answer : The most ideal option is furniture made from natural wood. Such material is environmentally friendly, however, many varieties of valuable species are quite expensive. In view of the limited family ... your liking, because, despite its versatility and safety, it should please and bring pleasure.
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5 views
1 answer
asked
Mar 29, 2021
by
anonymous
Suggest the diode material suitable to rectify 0.5V AC signal.
Last Answer : The diode material suitable to rectify 0.5V AC signal is silicon
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180 views
1 answer
asked
May 16, 2020
by
anonymous
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(i) Explain the process of diffusion in semiconductor material. (ii) Explain Hall effect.
Last Answer : (i) Diffusion: In a semi conductor bar a concentration gradient exist when either number of electrons or holes is greater in one region of a semi conductor as compared to other region. When ... to determine whether a semiconductor is N type or P type, and to find carrier concentration
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132 views
1 answer
asked
Aug 5, 2019
by
anonymous
Write one application for the give dielectric material. (i) Polyvinyl Carbide(PVC) (ii) Glass (iii) Mica (iv) Cotton and Silk
Last Answer : (i) Polyvinyl Carbide(PVC):it is used in insulation of wires and cables in domestic wiring as well as in aircraft and factory wiring (any one) (ii) Glass: 1) Alkaline glasses are used for ... with wax or varnishes are used in windings of magnet coils and small medium sized mechanics (any one)
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138 views
1 answer
asked
Aug 4, 2019
by
anonymous
