STED COUNCIL ELECTRICAL QA\QC 2022 SCHEME 0% STED COUNCIL (QA/QC) Online Exam Your NameEmail-idPhone Number 1 / 50 The field coils of D.C generator are made of copper cast iron carbon mica 2 / 50 For 66Kv lines the number of insulator disc are used 6 8 2 10 3 / 50 In which of the following motors the stator and rotor magnetic field rotate at the same speed induction motor synchronous motor universal motor reluctance motor 4 / 50 Form factor for a sine wave is 1.414 0.707 1.11 0.637 5 / 50 The conductors of the overhead lines are Solid None of the above Stranded Both (a) and (b) 6 / 50 How much current is produced by a voltage of 18kV across a 15-kilo ohm resistance? 1.2A 12mA 120mA 12A 7 / 50 Distribution lines in India generally use None of the above R.C.C poles Wooden poles Steel towers 8 / 50 A series motor is best suited for driving machine tools none of the above cranes and hoists shear and punches 9 / 50 Permissible current density of GI These motors are not self-starting To restrict armature current as there is no back emf while starting These motors have high starting torque Back emf of these motors is initially zero test wrong answer test right answer 10 / 50 Transformer ratings are given in HP kVAR KW kVA 11 / 50 The speed of a synchronous motor none of the above always remain constant increases as the load increases decreases as the load decreases 12 / 50 Relation between phase voltage and line voltage in three phase delta connected system Vline= 1.41Vphase Vline= Vphase/1.73 Vline= Vphase Vline= 1.73Vphase test wrong answer test right answer 13 / 50 Breaking capacity of a circuit breaker is usually expressed in terms of MVA amperes volts MW 14 / 50 A 3-phase 4-wire system is commonly used on Secondary transmission Secondary distribution Primary distribution Primary transmission 15 / 50 The fuse rating is expressed in terms of VAR current voltage kVA 16 / 50 The algebraic sum of voltages around any closed path in a network is equal to infinity negative polarity 1 0 17 / 50 Fuse protection is used for current ratings up to 10A 20A 100A 50A 18 / 50 The chemical used in breather for transformer should have the quality of cooling the transformer oil cleansing the transformer oil ionizing air absorbing moisture 19 / 50 Laminated core in electrical machines are used to reduce eddy current loss copper loss hysteresis loss all of the above 20 / 50 Which type of wiring system is suitable for multistorey building looping out with junction box Ring main system Tree system distribution board system 21 / 50 Differential relays use the principle of Frequency domain analysis Current magnitude comparison between incoming and outgoing feeder Time domain comparison 22 / 50 For which motors DOL starter can be used Up to 20 H.P Up to 5 H.P Up to 10 H.P Up to 15 H.P 23 / 50 The insulating material of a cable should have high dielectric strength all of the above high mechanical strength low-cost 24 / 50 The frequency of domestic power supply in India is 200 Hz 100 Hz 50 Hz 60 Hz 25 / 50 What is the insulation breakdown voltage of a cable 1000V 880V 1200V 1100V 26 / 50 Capacitors for power factor correction are rated in kW kVAR kV kVA 27 / 50 Starters are used with D.C motors because To restrict armature current as there is no back emf while starting Back emf of these motors is initially zero These motors are not self-starting These motors have high starting torque test wrong answer test right answer 28 / 50 Moisture content in the soil _______ earth soil resistance none of the above increase decrease does not affect 29 / 50 Transmission line insulators are made of iron glass porcelain P.V.C 30 / 50 Power factor of the following circuit will be unity capacitance inductance resistance both (a) and (b) 31 / 50 What is the standard size of GI earth wire in domestic installation 12 SWG 10 SWG 14 SWG 8 SWG 32 / 50 The voltage of the single-phase supply to residential consumer is 400V 210V 230V 110V 33 / 50 Overhead system can be designed for operation up to 11kV 33kV 66kV 400kV 34 / 50 What will happen if DC motor is used without starter Depends on load Will not start at all It will start smoothly Heavy sparking at brushes 35 / 50 The primary winding of a transformer has a 120V ac supply. What is the value of secondary voltage if the turns ratio is 10 12V 120V 1200V 12000V 36 / 50 In a cable immediately above, metallic sheath _______ is provided none of the above earthing connection bedding armouring 37 / 50 3-point starter is used to start the Both (b) and (c) series motor shunt motor compound motor 38 / 50 Which of the following does not change in an ordinary transformer Current Frequency Voltage all of the above 39 / 50 A fuse is connected none of the above in parallel with the circuit either in series or parallel with the circuit in series with the circuit 40 / 50 The operating voltage of high-tension cables is up to 66kV 33kV 6.6kV 11kV 41 / 50 Which of the following circuit element stores energy in the electromagnetic field inductance variable resistor resistance condenser 42 / 50 The medium employed for extinction of arc in air circuit breaker is air oil SF6 vacuum 43 / 50 Sulphur hexafluoride is a inactive gas conductor dielectric semiconductor 44 / 50 Pin type insulators are not used for voltages beyond 11kV 1kV 22kV 33kV 45 / 50 The filament of electric bulb is made of tungsten nickel carbon aluminum 46 / 50 Factors on which soil resistance depends moisture salt all of the above depth of electrode 47 / 50 H.R.C fuses provide best protection against open circuits overload reverse current short circuits 48 / 50 The operating voltage of extra high-tension cables is up to 66kV 6.6kV 33kV 11kV 49 / 50 The material commonly used for sheath of underground cables is Iron Lead Rubber Copper 50 / 50 In an induction motor, rotor slots are usually not quite parallel to the shaft but are given a slight skew To reduce the magnetic hum Both (a) and (b) To reduce the locking tendency of the rotor To increase the speed of the rotor Your score is 0%
