Which type of motor is used in trains, what is the rating of supply used?

1 Answer

Answer :

A:Dc series is in the trains to get high starting torque while starting of the trains and operating voltage is 1500v dc.

Related questions

Description : What are the various types of tariff?

Last Answer : 1. Simple tariff 2. Flat rate tariff 3. Block rate tariff 4. Two-part tariff 5. Maximum demand tariff 6. Power factor tariff 7. Three-part tariff

Description : What is tariff?

Last Answer : The rate at which electrical energy is supplied to a consumer is known as tariff. The tariff should include the following items: (i) Recovery of cost of producing electrical energy at the power ... of cost of operation and maintenance of supply (iv) A suitable profit on the capital investment.

Description : How can we reduce the effect of corona?

Last Answer : 1. By increasing conductor size: By increasing conductor size, the voltage at which corona occurs is raised and hence corona effects are considerably reduced. 2. By increasing conductor spacing: ... , the voltage at which corona occurs is raised and hence corona effects can be eliminated.

Description : What is corona?

Last Answer : The phenomenon of violet glow, hissing noise and production of ozone gas in an overhead transmission line is known as corona.

Description : What is meant by Sag?

Last Answer : The difference in level between points of supports and the lowest point on the conductor is called sag.

Description : What is difference between fuse and breaker?

Last Answer : A: (i) Fuse performs both detection and interruption functions. Circuit breaker performs interruption function only. The detection of fault is made by relay system. (ii) The breaking capacity of ... , replacement is required in the fuse. In case of circuit breaker, replacement is not required.

Description : Why we use ac system in India why not dc ?

Last Answer : A:Firstly, the output of power stations comes from a rotary turbine, which by it's nature is AC and therefore requires no power electronics to convert to DC. Secondly it is much easier to ... the sine wave current will naturally tend to zero at some point making the current easier to interrupt.

Description : Why electricity in India is in the multiples of 11 like 11kv, 22kv, 33kv ?

Last Answer : A:Transformer Induced voltage equation contains 4.44 factor. E -Induced emf per phase T -number of turns f -frequency Φ -maximum flux per pole From the equation we see that E is proportional to 4.4 and it is in turn multiple of 11.So always transmission voltage is multiple of 11

Description : When we connect the large capacitor bank in series ?

Last Answer : A :we connect large capacitor bank in series to improve the voltage power supply at the load end in balanced transmission line when there is considerable voltage drop along the balanced transmission line due ... - %6 )of the rated high terminal voltage )the large capacitor bank is used in series.

Description : What is reverse power relay?

Last Answer : A:Reverse Power flow relay are used in generating stations's protection. A generating stations is supposed to fed power to the grid and in case generating units are off,there is no generation in the ... power from grid. To stop the flow of power from grid to generator we use reverse power relay.

Description : What is the difference between over voltage relay and over current relay?

Last Answer : A:The current increases not only for over voltages but also for under voltage(As most of the loads are non-linear in nature). So,the over voltage protection & over current protection are completely ... , for a better protection of the system.It should have both over voltage & over current relay.

Description : What is derating?

Last Answer : A:The current currying of cables will change depending upon the site temperature (location of site), type of run (it will run through duct, trench, buried etc.), number of tray, depth ... of cable reduce than current currying capacity (which given to cable Catalogue) this is called derating.

Description : Define IDMT relay?

Last Answer : It is an Inverse Definite Minimum Time relay. In IDMT relay its operating is inversely proportional and also a characteristic of minimum time after which this relay operates. It is inverse in the sense; the tripping time will decrease as the magnitude of fault current increase.

Description : Where should the lighting arrestor be placed in distribution lines?

Last Answer : A:Near distribution transformers and out going feeders of 11kv and incomming feeder of 33kv and near power transformers in sub-stations.

Description : What is the difference between MCB & MCCB, Where it can be used?

Last Answer : A: MCB is miniature circuit breaker which is thermal operated for overload condition and magnetically operated for short circuit protection. It is available in small current rating. MCCB is moulded case ... frequency may be inbuilt. Normally it is used where normal current is more than 100 A.

Description : Explain types of Earthing.

Last Answer : A:The two types of earthing are Equipment earthing and system earthing. In Equipment earthing: body ( non conducting part) of the equipment should be earthed to safegaurd the human beings ... . This type of earthing is further classified into directly earthed, Impedance earthing, resistive earthing.

Description : What is Ferranti effect?

Last Answer : A: When receiving end voltage is greater than the sending end voltage.

Description : What is buchholz relay and the significance of it in to the transformer?

Last Answer : A:Buchholz relay is a gas based relay which is used for the protection of transformer from its internal faults. whenever any internal fault occurs in a transformer, the buchholz relay at once gives an ... then it stop its sound itself other wise it trips the circuit by its own tripping mechanism.

Description : What is the difference between Isolator and Circuit Breaker?

Last Answer : A: Isolator is a off load device which is used for isolating the downstream circuits from upstream circuits for the reason of any maintenance on downstream circuits. it is manually operated ... specification 1) rated current 2) short circuit breaking capacity and 3) Instantaneous tripping current.

Description : what is power factor? whether it should be high or low? why?

Last Answer : A:Power factor is the ratio of true power to apparent power. It has to be ideally 1. If it is too low then cable over heating & equipment overloading will occur. if it is greater than 1 then load will ... : 0.95 to meet actual power, load has to draw less current(V constant),result in less losses).

Description : Explain the working principle of the circuit breaker

Last Answer : A:Circuit Breaker is one which makes or breaks the circuit.It has two contacts namely fixed contact & moving contact. Under normal condition the moving contact comes in contact with fixed contact thereby forming ... . Arc is extinguished by the Arc Quenching media like air, oil, vacuum, SF6 gas etc.

Description : What is the difference between surge arrestor and lightning arrestor?

Last Answer : A:Lightning Arrestor is installed outside and the effect of lightning is grounded where as surge arrestor installed inside panels comprising of resistors which consumes the energy and nullify the effect of surge.

Description : Why we use Vacuum Circuit Breaker in High Transmission System and not Air Circuit Breaker?

Last Answer : A:Vacuum has high arc quenching property compare to air . The dielectric strength of vacuum is equal to 8 times than air . Hence vacuum circuit breaker is used in High voltage line and air circuit breaker is used in low voltage lines.

Description : Why syn. generators are used for the production of electricity?

Last Answer : A:synchronous machines have capability to work on different power factor. Hence syn. generators are used for the production of electricity.

Description : What will happen when power factor is leading in distribution of power?

Last Answer : A:If their is high power factor, i.e if the power factor is close to one: 1.losses in form of heat will be reduced, 2.cable becomes less bulky and easy to carry, and very cheap to afford, & 3. it also reduces over heating of transformers.

Description : what is ACSR cable and where we use it?

Last Answer : A: ACSR means Aluminium conductor steel reinforced, this conductor is used in transmission & distribution.

Description : Describe the operation carried out in Thermal power stations?

Last Answer : A:The water is boiled in the boiler with the help of coal. This generates steam. This steam is allowed to hit the turbine hence the turbine rotates. The turbine is coupled with generator. So the mechanical energy of turbine is converted to electrical energy by Generator.

Description : What is "pu" in electrical engineering?

Last Answer : PU stands for per unit and this will be used in power system single line diagram there it is like a huge electrical circuit with no of components (generators, transformers, loads) with different ratings (in ... into this basis. Those values are called as pu values. (p.u=actual value/base value).

Description : What is Electric traction?

Last Answer : A:Electric traction means using the electric power for traction system to drive the locomotives.

Description : What is meant by synchronous condenser?

Last Answer : An over excited synchronous motor running on no load is known as synchronous condenser. It is used to improve the power factor of the system.

Description : The rating of the Transformer __ when the supply frequency is increased: a) Remains unchanged b) Increases c) Decreases d) None of the above

Last Answer : Ans: B

Description : AC and DC generators are similar in that they _____________. A. both generate alternating voltages B. both rectify the voltage before delivery C. are constructed at the same physical size for the same kilowatt rating D. both supply three-phase power

Last Answer : Answer: A

Description : Name the mode of transportation that reduces trains-shipment losses and delays in the supply of petroleum and gases? -SST 10th

Last Answer : Pipelinesis the mode of transportation that reduces trains-shipment losses and delays in the supply of petroleum and gases.

Description : Describe the reason of using dc series motor for electric trains.

Last Answer : Electric trains require an inverse torque speed characteristics for proper operation. That is a higher torque is required at start (when speed is nil or low) and as the train picks up ... torque - speed characteristics of DC series motors match, these motors are suitable for electric trains

Description : In a three-phase, squirrel-cage type, induction motor the rotating magnetic field is established by the _____________. A. current induced in the rotor windings B. application of a three-phase voltage ... caused by the induced current in the squirrel-cage bars with the magnetic field of the stator

Last Answer : Answer: B

Description : If the supply voltage is 220 volts 60 Hz, what is the operating voltage of the motor controller circuitry illustrated? EL-0011 A. 110 volts DC B. 110 volts AC C. 220 volts DC D. 220 volts AC

Last Answer : Answer: D

Description : A series wound DC motor has its armature and field connected in series with a resistor. When the motor is disconnected from its power supply, this motor will exemplify __________. A. the ... the proper connections for an automatic strip heater C. a reversing controller circuit D. dynamic braking

Last Answer : Answer: D

Description : When testing for blown fuses in a three-phase supply circuit to a motor, you should first ___________________. A. apply the megger across the tops of the line fuses B. apply an ammeter diagonally across ... of the line fuses D. ensure the circuit is de-energized, and then use a continuity tester

Last Answer : Answer: D

Description : If a three-phase induction motor is operated under a light load and it develops an open in one of its supply lines, the motor will _____________. A. continue to run, but will vibrate and have reduced ... speed up due to the reduced number of poles C. run cooler due to reduced current flow D. stop

Last Answer : Answer: A

Description : If a three-phase induction motor malfunctions and drops to a single-phase (one supply line open) ____________. A. the motor will continue to run if it is not heavily loaded B. more torque will be ... be able to be restarted D. the motor will immediately stop and can only be restarted at no load

Last Answer : Answer: A

Description : The most common source of excitation for synchronous motors is a/an _____________. A. low voltage battery B. motor attenuator set C. DC exciter generator D. AC supply

Last Answer : Answer: C

Description : Which of the following statements represents an application of a silicon controlled rectifier? A. To provide DC power for a main propulsion motor. B. For use as a voltage reference diode. C. For sensing flame in an automated burner. D. To eliminate power supply hum.

Last Answer : Answer: A

Description : Indicate how you will select the limit switch contacts for indication and for cutting the supply to the motor? 

Last Answer : For cutting off the supply to the motor normally closed (NC) contacts of limit switch (LS) should be wired in series with interposing relay coil of respective direction of the valve so that when ... should remain NC only and vice-versa. So for close direction NC contact of close direction  

Description : The direction of rotation of hysteresis motor is reversed by (A) Shift shaded pole with respect to main pole (B) Reversing supply lead (C) Either A or B (D) Neither A nor B

Last Answer : Ans: A This motor used single phase, 50Hz supply and stator has two windings. These are connected continuously from starting to running.

Description : A dc shunt generator has a speed of 800 rpm when delivering 20 A to the load at the terminal voltage of 220V. If the same machine is run as a motor it takes a line current of 20A from 220V supply. The speed of ... . (B) more than 800 rpm. (C) less than 800 rpm. (D) both higher or lower than 800 rpm.

Last Answer : (C) less than 800 rpm.

Description : A relay has a rating of 5 A, 2.2 sec IDMT and a relay setting of 125% TMS = 0.6. It is connected to a supply circuit through a C.T. 400/5 ratio. The fault current is 4000 A. The operating current of the relay is

Last Answer : A relay has a rating of 5 A, 2.2 sec IDMT and a relay setting of 125% TMS = 0.6. It is connected to a supply circuit through a C.T. 400/5 ratio. The fault current is 4000 A. The operating current of the relay is 6.25A

Description : If a fuse of correct size and type blows frequently, ________________. A. try the next higher amperage rating B. try the next lower amperage rating C. look for trouble within the circuit D. reduce the applied voltage 10%

Last Answer : Answer: C