3kW load is supplied by an autotransformer with 0.7 transformation ratio. Conductively transferred power from primary to secondary is 2.1 kW
Description : Auto-transformer makes effective saving on copper and copper losses, when its transformation ratio is?
Last Answer : Auto-transformer makes effective saving on copper and copper losses, when its transformation ratio is approximately equal to 1.
Description : Use of auto-transformer is economical when the transformation ratio is?
Last Answer : Use of auto-transformer is economical when the transformation ratio is near unity.
Description : An Auto-transformer (which has only one winding) may be used as a ______ . (A) Both Step-Up and Step-Down transformer (B) Step-Down Transformer (C) Step-Up Transformer (D) None of these
Last Answer : An auto-transformer may be used as: A. Both Step-Up and Step-Down transformer An auto-transformer is a type of transformer that has only one winding and can be used as a step-up or ... size. Therefore, an auto-transformer is a versatile transformer that can be used for a variety of applications.
Description : Indicate the false statement. Noise figure is defined as A. the ratio of the S/N power supplied at the input terminal of a receiver or amplifier to the S/N power supplied to the output or ... under test, both working at the same temperature over the same bandwidth and fed from the same source
Last Answer : C. an unwanted form of energy tending to interfere with the proper and easy reception and reproduction of wanted signals
Description : The heat Q per unit mass per degree change in temperature that must be supplied or removed to change the temperature of a substance. a. Specific Heat Capacity b. Latent Heat c. Heat of Transformation d. Internal Heat
Last Answer : Specific Heat Capacity
Description : The two windings of a transformer is (A) conductively linked. (B) inductively linked. (C) not linked at all. (D) electrically linked.
Last Answer : (B) inductively linked.
Description : In case of conductively compensated D.C. series motors, the compensating winding is provided?
Last Answer : In case of conductively compensated D.C. series motors, the compensating winding is provided in series with armature winding.
Description : An autotransformer is equipped with a 50% tap, a 65% tap, and an 80% tap. Which of the following statements is true concerning a load connected to the 50% tap? A. The load is ... is receiving maximum voltage and minimum current. D. The load is receiving maximum voltage and maximum current.
Last Answer : Answer: B
Description : Draw the power and control circuit for motors using autotransformer type starter.
Last Answer : Draw the power and control circuit for motors using autotransformer type starter.
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 : Transformation refers to a. Using A Virus To Transfer DNA Fragments. b. DNA Fragments Transferred Between Live Donor And Recipient Cells. c. The Formation of an F- Recombinant Cell. d. The Transfer of Naked Fragments of DNA
Last Answer : b. DNA Fragments Transferred Between Live Donor And Recipient Cells.
Description : State with neat sketch the construction of three phase autotransformer.
Last Answer : Operation: Working principle is based on self-induction. When three-phase ac supply is given to star connected three windings, flux is produced and gets linked with each phase winding. The emf ... . Depending upon the position of variable terminal, we get variable AC voltage at the output.
Last Answer : 由BillC - 自己的作品，CC BY-SA 3.0，链接 Autotransformer is a special case in which one coil becomes part of another coil. Autotransformers are also often used for motor starting. Autotransformer ... low loss, low cost and widely used. source: https://zh.wikipedia.org/zh-hans/%E5%8F%98%E5%8E%8B%E5%99%A8
Description : A properly matched transmission line has a loss of 1.5 dB/100m. if 10 W is supplied to one end of the line, how many watts reach the load, 27 m away? A. 10 W B. 7.2 W C. 9.9 W D. 9.1 W
Last Answer : D. 9.1 W
Description : The device shown in the illustration is a/an ____________. EL-0083 A. noise filtering choke B. autotransformer C. fluorescent light ballast D. power factor correction inductor
Description : (a) Define permeability. (b) Define MMF. (c) Define form factor of an alternating quantity. (d) Define frequency and time period of an alternating quality. (e) Define transformation ratio of transformer. ... and state the meaning of each term used. (g) Give two applications of single phase motors.
Last Answer : Permeability : It is the ability of a magnetic/Non magnetic material to allow setting up of flux in it. MMF : The magneto motive force (MMF) is the force required to setup flux in a magnetic / ... applications of single phase motors : Water pumps, ceiling fan, lathe machine
Description : The electrical schematic illustrated in figure A, depicts a/an _____________. EL-0059 A. autotransformer B. Delta Wye transformer C. primary EMF generator D. potential transformer
Last Answer : Answer: D
Description : The electrical schematic shown in the illustration represents a/an ____________. EL-0017 A. across-the-line starter B. primary-resistor starter C. autotransformer starter D. part-winding starter
Last Answer : Answer: A
Description : The diagram shown in the illustration represents a/an _____________. EL-0082 A. stepup transformer B. magnetic amplifier C. autotransformer D. Scott-connected transformer
Description : Which of the listed types of motor controllers and starters is illustrated? EL-0080 A. Across-the-line B. Primary-resistor C. Autotransformer D. Part-winding
Last Answer : Answer: C
Description : The voltage at the reference electrode of the circuit shown in the illustration is applied to the input of a/an ______________. EL-0090 A. class A detector whose output drives an ... drives an 2-stage isolation transformer D. magnetic amplifier whose output controls a saturable reactor
Description : Most three-phase induction motors of five horsepower or less, are started by _____________. A. autotransformer starters B. resistor starters C. across-the-line starters D. reactor starters
Description : Autotransformer starters or compensators are sometimes used with polyphase induction motors to _____________. A. reduce the voltage applied to the motor during the starting period B. increase the voltage for ' ... to be either stepped up or down, depending on the application, to ensure full torque
Description : In general, polyphase induction motors can be started on full line voltage by means of ______________. A. compensator starters B. autotransformer starters C. across-the-line starters D. primary-resistor starters
Description : Low horsepower, polyphase, induction motors can be started with full voltage by means of _____________. A. compensator starters B. autotransformer starters C. across-the-line starters D. primary-resistor starters
Description : As shown in the illustration, which of the listed types of motor controllers and starters is indicated? EL-0012 A. Across-the-line B. Capacitor C. Autotransformer D. Part-winding
Description : List the merits of an autotransformer.
Last Answer : Require less conductor material low cost low size high VA rating high efficiency Better voltage regulation small amount of no load current
Description : Compare autotransformer with two winding transformer.
Last Answer : Two winding transformer Auto transformer 1.It has two separate windings : a) primary, b)secondary. 1. An auto transformer has single winding which acts both as primary and secondary ... varied. 3. They find application as boosters in AC feeders to increase the voltage levels.
Description : State any two applications of single phase autotransformer.
Last Answer : Applications of single phase auto transformers: 1) Give small boost to distribution cable to correct the voltage drop. 2) As auto transformer starter for induction motors. 3) As furnace supply ... . 5) In control equipment for single phase locomotives. 6) As dimmer in lighting circuits.
Description : Autotransformer
Last Answer : .embed-container { position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; } .embed-container iframe, .embed-container object, .embed-container embed { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }
Description : In conversion of 3-phase to 2-phase supply with T connection, the transformation ratio of the teaser will be__ times to that of main transformer: a) 1.732 b) 1.15 c) 0.866 d) Unity
Last Answer : Ans: C
Description : Amount of coal lost in ash particle, which is carried through the boiler system, depends upon the (A) Physical nature, ash content and fineness of the coal (B) Amount of excess air supplied and load on the boiler (C) Type of burner and combustion chamber (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : During short circuit test iron losses are negligible because A. The current on secondary side is negligible B. The voltage on secondary side does not vary C. The voltage applied on primary side is low D. Full-load current is not supplied to the transformer
Last Answer : C) the voltage applied on primary side is low
Description : If the energy is supplied from a source, whose resistance is 1 ohm, to a load of 100 ohms the source will be?
Last Answer : If the energy is supplied from a source, whose resistance is 1 ohm, to a load of 100 ohms the source will be a voltage source.
Description : The synchronous speed of an 8 pole induction motor supplied power from a 50 Hz source will be ?
Last Answer : Ns equals f/pair pole 50/4 - 12.5
Description : Energy to be supplied to the radioactive nucleus for the emission of a neutron is __________ MeV. (A) 0.8 (B) 7.8 (C) 200 (D) 10000
Last Answer : (A) 0.8
Description : For a short transmission line with r/x ratio of is 1.0, the regulation will be zero when the load power factor is
Last Answer : For a short transmission line with r/x ratio of is 1.0, the regulation will be zero when the load power factor is 0.707 lead
Description : The load transferred from rails to web of girders is in a) deck type girder b) through type girder c) semi-through type girder* d) plate girder
Last Answer : c) semi-through type girder*
Description : The load transferred from rails to bottom flanges is in a) deck type girder b) through type girder* c) semi-through type girder d) plate girder
Last Answer : b) through type girder*
Description : An engine working on air standard Otto cycle has a cylinder diameter of 10 cm and stroke length of 15 cm. The ratio of specific heats for air is 1.4. If the clearance volume is 196.3 cc and the heat supplied per kg of air per ... kg of air is a. 879.1 kJ/ b. 890.2 kJ c. 895.3 kJ d. 973.5 kJ
Last Answer : ANSWER d. 973.5 kJ
Description : The efficiency of the Otto cycle is independent of a. Heat supplied b. Compression ratio c. Ratio of specific heats d. None of the above
Last Answer : Answer a. Heat supplied
Description : Maximum power is transferred when
Last Answer : Maximum power is transferred when Load Impedance = source impedance
Description : If X is the system reactance and R is its resistance, the power transferred is maximum when (1) X=R (2) X=1.414 R (3) X=1.732 R (4) X=2R
Last Answer : x = 1.732R
Description : The power supplied to a motor is six kilowatts at 120 volts. What is the impedance of the motor? A. 0.05 Ohms B. 0.50 Ohms C. 2.40 Ohms D. 24.00 Ohms
Description : What is transformation ratio for step up, step down and isolation transformer?
Last Answer : K>1 for step up transformer K
Description : What is voltage transformation ratio or turn ratio?
Last Answer : It is expressed as ratio of the primary and secondary voltages of transformer. or It is expressed as ratio of the primary and secondary turns of transformer. E1/ E2= T1/T2 = K
Description : What is the transformation ratio in transformer?
Last Answer : Equation for transformation ratio is, E2/E1 = N2/N1 = k k = >1 in step up transformer, where secondary turns are more and thus voltage is more to reduce the transmission current. k =
Description : Define transformation ratio of a transformer.
Last Answer : Transformation Ratio (K) of a transformer: It is the ratio of secondary number of turns to primary number of turns. (OR) It is the ratio of secondary voltage to primary voltage. (OR ) It is the ratio of primary current to secondary current. OR
Description : Define transformation ratio in terms of current and voltage.
Last Answer : (i) Transformation Ratio (K) is defined as the ratio of the primary current to the secondary current. (ii) Transformation Ratio (K) is defined as the ratio of the secondary voltage to the primary voltage.