# Overhead lines for power supply to tramcars are at a minimum height of?

Overhead lines for power supply to tramcars are at a minimum height of 10 m.

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Description : A minimum clearance of 6.3 m to ground is required for overhead lines when operating voltages are :  (A) less than 66 kV (B) lie between 66 kV and 110 kV (C) more than 165 kV (D) lie between 110 kV and 165 kV

Last Answer : A minimum clearance of 6.3 m to ground is required for overhead lines when operating voltages are : lie between 66 kV and 110 kV

Description : Why are overhead transmission lines not insulated?

Last Answer : Insulators are useful to help separate electrical conductors when they come into physical contact. Overhead Transmission Lines Are Not Insulated: The overhead transmission line is carrying extreme high voltage and ... a whole lot of thick insulation to absorb the heat produced by such high voltage.

Description : Why ACSR conductor is used for overhead lines?

Last Answer : It has high tensile strength

Description : State the effects of low power factor on efficiency and voltage regulation of short transmission lines.

Last Answer : i) Effect of Low power factor on efficiency:- When power factor of load reduces current drawn by transmission line increases so copper losses in transmission line increases, hence transmission ... increases, so voltage drop in transmission line increases so regulation increases. (Become Poor)

Description : Why don't we burry power lines underground ?

Last Answer : Because conductor used for power transmission are not insulated and if we do so it create phase to ground fault causing interruptions to supply.

Description : In tuned power lines, on load :  (A) the receiving end voltage is numerically equal to the sending end voltage  (B) the receiving end current is numerically equal to the sending end current  (C) there is no voltage drop  (D) all the above

Last Answer : In tuned power lines, on load :  (A) the receiving end voltage is numerically equal to the sending end voltage  (B) the receiving end current is numerically equal to the sending end current  (C) there is no voltage drop  (D) all the above

Description : Draw the block diagram of regulated power supply, explain function of each block and draw waveforms of each stage.

Last Answer : 1. A step down transformer 2. A rectifier 3. A filter 4. A regulator Operation of Regulated Power Supply:- Step Down Transformer:- A step down transformer will ... regulator. A regulator will maintain the output constant even when changes at the input or any other changes occur.

Description : What is need of regulated power supply?

Last Answer : A regulated power supply is used to ensure that the output remains constant even if the input changes. But sometimes main supply voltage, load, and surrounding temperature keep changing and altering the ... power supply is needed that will accept an AC input and give a constant DC output.

Description : What is the Power Supply specification for 8085AH microprocessor? A) Single +5V supply with 10% voltage margins B) Dual +5V supply with 10% voltage margins C) Single +10V supply with 5% voltage margins D) Dual +5V supply with 5% voltage margins

Last Answer : What is the Power Supply specification for 8085AH microprocessor? A) Single +5V supply with 10% voltage margins B) Dual +5V supply with 10% voltage margins C) Single +10V supply with 5% voltage margins D) Dual +5V supply with 5% voltage margins

Description : Two 100W, 200V lamps are connected in series across a 200V supply. The total power consumed by each lamp will be in Watts

Description : The time period of third harmonic of power supply frequency, in milliseconds, is (A) 20 (B) 3.33 (C) 6.66 (D) 60

Last Answer : The time period of third harmonic of power supply frequency, in milliseconds, is 6.66

Last Answer : The primary reason for low power factor is supply system is due to installation of induction motors.

Last Answer : For high value of diversity factor, a power station of given installed capacity will be in a position to supply more number of consumers.

Last Answer : Rectifier is use in power supply to convert Alternating current (AC) to Direct Current (DC) .

Description : The supply for arc welding is :

Last Answer : The supply for arc welding is : Low voltage, high current ac or dc voltage

Description : Differentiate between overhead transmission and underground transmission.

Last Answer : Points Overhead line  Underground cable Capital cost  Less More Erecting cost  Less More Time require for completion of work Less More Flexibility More ... Space consumed Space consumed  No space consumed Appearance Not good  Very good

Description : 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.

Description : Why underground service connections are service connections are costly than overhead service connection

Last Answer : Reason: Underground service connection is given by underground cable. This cable is costly than bare conductor. Sometimes cable trench is required for cable laying, which requires additional cost. So underground service connections are costly than overhead service connection.

Description : Define service connection and state types connection and state types of overhead service connection

Last Answer : Service Connection:- It is the input conductor or wire which is carried out from supply company (authorities) pole to consumers' main board or premises. Types of overhead service ...  1. Overhead service connection with Bare conductor 2. Overhead service connection with weather proof cable

Description : lf a travelling-wave travelling along a loss-less overhead line does not result in any reflection after it has reached the far end, then the far end of the line is

Last Answer : lf a travelling-wave travelling along a loss-less overhead line does not result in any reflection after it has reached the far end, then the far end of the line is terminated into a resistance equal to surge impedance of the line

Last Answer : Overhead system can be designed for operation up to 400 kV.

Description : State the classification of transmission lines depending on length of transmission lines.

Last Answer : A) According to Voltage level: ( 2 Marks)  a) High voltage Transmission Line (HV) up to 33 KV  b) Extra High Voltage Transmission Line (EHV) above 33 KV up to 400 KV  c) Ultra ... Transmission Line: - The length of Long transmission Line is above 200KM and its line voltage is above 100KV

Description : Find out number of data lines required to interface 16 LEDs arrange in the 4 x 4 matrix form.

Last Answer : 4+4=8, eight lines are required for 4x4 matrix of 16 LEDs

Description : Define magnetic lines of force. Also draw and show magnetic lines of force of a bar type magnet.

Last Answer : Magnetic Lines of force- These are the imaginary lines (having no physical existence) introduced by Faraday for the pictorial representation of the distribution of a magnetic field.  OR  A line of ... that the tangent at any point gives direction of the resultant force at that point.

Description : Define magnetic lines of force. Show the magnetic lines of force for bar type magnet.

Last Answer : Magnetic linens of force is the imaginary lines for magnetic field of magnet around it. These magnetic lines of forces are introduced by Michael Faraday. The direction of lines of force is from N-pole to S-pole. The figure shows lines of force for bar type magnet.

Description : In which of the following transmission lines, the value of the Shunt admittance should be approximated to zero ? (A) A 66 kV 35 km long line (B) A 132 kV 200 km long line (C) A 220 kV 300 km long line (D) A 400 kV 500 km long line

Last Answer : In which of the following transmission lines, the value of the Shunt admittance should be approximated to zero ? (A) A 66 kV 35 km long line (B) A 132 kV 200 km long line (C) A 220 kV 300 km long line (D) A 400 kV 500 km long line

Description : The purpose of guard ring in transmission lines is to  (1) reduce the earth capacitance of the lowest unit. (2) increase the earth capacitance of the lowest unit. (3) reduce the transmission lines losses. (4) reduce the reactance of the line

Last Answer : The purpose of guard ring in transmission lines is to reduce the earth capacitance of the lowest unit.

Description : Which of the following is the name given to the lines of electric force which move so that its beginning traces a closed curve on a positive surface and its end traces a corresponding closed curve on the negative surface? A) Tube of surface B) Tube of lines C) Tube of force D) Tube of electricity

Last Answer : Which of the following is the name given to the lines of electric force which move so that its beginning traces a closed curve on a positive surface and its end traces a corresponding closed curve on the negative ... A) Tube of surface B) Tube of lines C) Tube of force D) Tube of electricity

Description : Corona loss in transmission lines can be reduced by (A) using small diameter conductors (B) using bundled conductors (C) using less spacing between conductors (D) increasing the transmission line voltage

Last Answer : Corona loss in transmission lines can be reduced by using bundled conductors

Description : If a 5-bus test system contains 6 transmission lines and one transformer, how many non-zero elements are there in the system Y-bus ? (A) 25 (B) 12 (C) 11 (D) 19

Last Answer : If a 5-bus test system contains 6 transmission lines and one transformer, 19 non-zero elements are there in the system Y-bus.

Last Answer : Series capacitors on transmission lines are of little use when the load VAR requirement is small.

Description : Total instantaneous power supplied by a 3-phase ac supply to a balanced R-L load is

Last Answer : Total instantaneous power supplied by a 3-phase ac supply to a balanced R-L load is constant

Description : How To Make An Emergency Supply Kit

Last Answer : How To Make An Emergency Supply Kit Accidents and natural disasters happen; they are among the unavoidable and unpleasant occurrences that happen in life. Unfortunately, we can't predict when and ... emergency supply kit properly, and you'll be able to make it through the catastrophe unscathed.

Description : Analyze the effect of supply voltage on performance of LED as regards current, Lumen output, efficacy and life.

Last Answer : 1) Effect on Current:- In LED current depends upon supply voltage, if voltage get changes then current also change but this change in current will be control by resistors which are connected in series.  2) ...   4) Effect on Life:- If supply voltage is not stable then life of LED get reduced.

Description : Define phase sequence of three phase supply with waveforms. What is normal phase sequence? Which 3 standard colours are used to denote the phase sequence?

Last Answer : It  is  sunnosoidal  sequence.

Description :  An AC supply of 230 V is applied to a half-wave rectifier circuit through a transformer having primary to secondary turn’s ratio 12:1. The peak inverse voltage is A) 8.62 V B) 12 V C) 19.17 V D) 27.11 V

Last Answer :  An AC supply of 230 V is applied to a half-wave rectifier circuit through a transformer having primary to secondary turn’s ratio 12:1. The peak inverse voltage is A) 8.62 V B) 12 V C) 19.17 V D) 27.11 V

Description : A change of 4% in the supply voltage to an induction motor will produce a change of approximately

Last Answer : A change of 4% in the supply voltage to an induction motor will produce a change of approximately 8% in the rotor torque

Description : We connected a 35V dc supply to a resistance of 600 Ohm in series with an unknown resistance R.A. voltmeter having a resistance of 1.2 kOhm is connected across 600 Ohm resistance and read 5v. The value of resistance R will be

Last Answer : We connected a 35V dc supply to a resistance of 600 Ohm in series with an unknown resistance R.A. voltmeter having a resistance of 1.2 kOhm is connected across 600 Ohm resistance and read 5v. The value of resistance R will be 2.4 kOhm

Description : What will happen if the primary of a transformer is connected to D.C. supply?  (A) Transformer will operate with low efficiency (B) Transformer will operate with high efficiency (C) No effect (D) Transformer may start to smoke and burn

Last Answer : What will happen if the primary of a transformer is connected to D.C. supply?  (A) Transformer will operate with low efficiency (B) Transformer will operate with high efficiency (C) No effect (D) Transformer may start to smoke and burn

Description : Consider a circuit with three parallel branches connected across a DC supply. What is the ratio of the branch currents I1 : I2 : I3 if the branch resistances are in the ratio of 2 : 3 : 4 respectively? A) 2 : 3 : 4 B) 6 : 4 : 3 C) 4 : 3 : 2 D) None of these

Last Answer : Consider a circuit with three parallel branches connected across a DC supply. What is the ratio of the branch currents I1 : I2 : I3 if the branch resistances are in the ratio of 2 : 3 : 4 respectively? A) 2 : 3 : 4 B) 6 : 4 : 3 C) 4 : 3 : 2 D) None of these

Description : 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

Description : In a three-phase supply floating neutral is undesirable because it way give rise to?

Last Answer : In a three-phase supply floating neutral is undesirable because it way give rise to unequal line voltages across the load.

Description : The effective resistance of an iron-cored choke working on ordinary supply frequency is more than its true resistance because of?

Last Answer : The effective resistance of an iron-cored choke working on ordinary supply frequency is more than its true resistance because of iron loss in core.

Last Answer : Reason is kinetic energy

Last Answer : If a D.C. series motor is operated on A.C. supply, it will spark excessively, have poor efficiency, have poor power factor.

Description : A capacitor-start single phase induction motor is switched on to supply with its capacitor replaced by an inductor of equivalent reactance value. It will?

Last Answer : A capacitor-start single phase induction motor is switched on to supply with its capacitor replaced by an inductor of equivalent reactance value. It will not start at all.

Last Answer : If the synchronous motor, properly synchronised to the supply is running on no load and is having negligible loss then the stator current will be zero.

Last Answer : If the supply frequency to the transformer is increased, the iron loss will increase.

Description : In a step-down transformer, there is a change of 15 A in the load current. This results in change of supply current of?

Last Answer : In a step-down transformer, there is a change of 15 A in the load current. This results in change of supply current of less than 15A.

Description : Why does a transformer only work with an AC supply?

Last Answer : The transformer work depends on the induction as main principle ,for that AC is the right means