Description : What is Colling Fan ?
Last Answer : A small fan , which is used to keep the processor cool by removing the heat generated in the processor. There is a ventilator outside to expel the heat generated by the air flow generated by the cooling fan. The cooler has to be connected to the processor socket.
Description : 5Star air conditioner will provide the same amount of colling using ___________ power than 1 star air conditioner of same tonnage. a) Lesser c) more b) Equal d) all of the above
Last Answer : Equal
Description : Why we do 2 types of earthing on transformer i.e.: body earthing & neutral earthing, what is function. I am going to install a 5oo kva transformer & 380 kva DG set what should the earthing value?
Last Answer : The two types of earthing are Familiar as Equipment earthing and system earthing. In Equipment earthing: body (non conducting part) of the equipment should be earthed to safeguard the human ... earthing will be further classified into directly earthed, Impedance earthing, resistive (NGRs) earthing.
Description : What are the various types of three phase transformer connections?
Last Answer : The most common types of transformer connections are, i. Star-Star (Y-Y) ii. Delta-Delta(∆-∆) iii. Star-Delta (Y-∆) iv. Delta-Star (∆-Y) v. Open Delta (V-V) vi. Scott Connection (T-T)
Description : What are the different types of faults in a transformer?
Last Answer : The internal faults include phase faults, ground faults, inter-turn faults, tap-changer failure, and leakage oil from tank. The external faults include system phase faults, system ground faults, over loads and over fluxing.
Description : What are the types of bushing used in transformer?
Last Answer : Condenser type bushing Porcelain type bushing
Description : What are the types of oil used for in transformer for cooling?
Last Answer : Paraffin based and naphtha based (in INDIA)
Description : What are the types of cooling in transformer?
Last Answer : 1. Natural cooling. a. Air natural cooling (Dry type). b. Oil immersed natural cooling. c. Oil immersed, forced oil circulation with natural cooling. 2. Artificial cooling. a. Oil immersed forced ... This is the method of cooling combining oil natural, water, air natural, air blast and forced oil.
Description : What are the types of transformer core?
Last Answer : a. Core type transformer core. b. Shell type transformer core. c. Berry type transformer core. d. Spiral type transformer core.
Description : In the illustrated 450 VAC system, what should be provided between the bus and the device labeled 'F'? EL-0003 A. a potential transformer B. a current transformer C. an emergency disconnect device D. an audible alarm and indicating light
Last Answer : Answer: A
Description : Figure 'A' of the diagram shown in the illustration represents a ______________. EL-0092 A. differential transformer B. saturable reactor C. synchro system D. magnetic amplifier
Last Answer : Answer: C
Description : A switchboard for an AC electrical system requires the use of which of the following devices? A. Frequency meter. B. Ohmmeter. C. Induction voltage regulator. D. Current transformer governor.
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 : The harmonic currents in a power transformer does not cause increase in: a) Secondary voltage b) Core loss c) Copper loss d) Magnetic interference with protective relays
Last Answer : Ans: A
Description : An auto transformer is preferred over an ordinary two winding transformer due to: a) Safety of operation b) Availability of taps on secondary c) Copper savings d) All the above
Description : In a transformer, with closed magnetic coupling between primary and secondary __ will improve: a) Efficiency b) All day efficiency c) Regulation d) None of the above
Description : Booster transformer should never: a) Have fuse in the HV winding b) Be left open circuited c) Be left closed circuited d) None of the above
Last Answer : Ans: B
Description : The rating of the Transformer __ when the supply frequency is increased: a) Remains unchanged b) Increases c) Decreases d) None of the above
Description : Stones are provided in the substation to: a) To avoid fire accident by draining oil from transformer if leaks b) To avoid growing of weeds and plants c) To provide insulation d) All the above
Last Answer : Ans: D
Description : A transformer has negative voltage regulation when its load power factor is- (a) Zero (b) Unity (c) Leading (d) Lagging
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 : Which of the listed electrical devices is represented by the symbol shown in the illustration? EL-0055 A. Fixed resistance resistor B. Coil with magnetic core C. DC motor or generator shunt field D. Transformer
Description : The symbol shown as figure 'A' represents a/an ____________. EL-0059 A. transformer B. coil C. shunt field D. inductor
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 : In electric circuit schematics, a transformer is represented by which of the symbols shown in the illustration? EL-0059 A. A B. B C. C D. D
Description : Which of the following statements identifies the difference between the primary windings and the secondary windings of a 2:1 stepdown transformer? A. The secondary windings have twice as much resistance ... primary windings. D. The secondary windings have half as many turns as the primary windings.
Description : An open coil in a transformer will be indicated by which of the listed conditions? A. 'zero' resistance accompanied by high inductance B. no resistance accompanied by stray inductance C. infinite resistance in addition to no inductance D. infinite resistance in addition to normal inductance
Description : A load with an impedance of 440 ohms is connected across the secondary of the transformer illustrated. If the input voltage is 110 VAC and the step-up ratio is 10 to 1, what will be the primary current? EL-0055 A. 2.5 amps B. 25 amps C. 250 amps D. current cannot be determined with information given
Last Answer : Answer: B
Description : The turns ratio of transformer 'A' shown in the illustration is four to one and all taps are evenly spaced. If 120 volts were applied to terminals 'H1' and 'H3', what would appear at 'X1' and 'X2'? EL-0082 A. 15 volts B. 30 volts C. 480 volts D. 960 volts
Description : A load is connected to the secondary of the transformer illustrated and the current through the load is 10 amps. If the step-up ratio is 10 to 1 and the input voltage is 110 VAC, what will be the current flow through the primary? EL-0055 A. 1 amp B. 10 amps C. 100 amps D. 1000 amps
Description : Which of the following statements is true concerning stepdown transformer operation? A. The inductance on the primary side is the same as the inductance on the secondary side. B. The voltage to the primary ... . D. The voltage to the primary side is greater than the voltage from the secondary side.
Description : When a low input voltage is imparted to a device which then delivers a high output voltage, the device is known as a _____________. A. primary transformer B. secondary transformer C. stepdown transformer D. stepup transformer
Description : In the illustrated circuit, if the input to leads 'B' and 'Y' was 24 VDC the output between 'A' and 'X' will be _________. EL-0069 A. 24 VDC B. 22.8 VDC, 24 VDC minus the 1.2 VDC voltage drop across two diodes C. undeterminable without knowing the turns ratio of the transformer D. 0 VDC
Description : A device used in an electrical circuit to change alternating current to direct current, is known as a _____________. A. current transformer B. rectifier C. condenser D. shunt
Description : When used for taking resistance measurements, a volt-ohm-milliammeter is normally powered by _____________. A. a hand cranked generator B. internal storage batteries C. the current in the circuit being tested D. a step down transformer
Description : In the illustrated electronic governor, the circuit card connected to the potential and current transformers is for ________. EL-0046 A. increasing the signal strength to the governor to ... from motorization D. conditioning the load through the use of a magnetic amplifier current transformer
Description : The transistors in the illustrated circuit are connected using what type of coupling? EL-0049 A. RC coupling B. transformer coupling C. LC coupling D. direct coupling
Description : The transistors in the illustrated circuit are connected using what type of coupling? EL-0048 A. RC coupling B. transformer coupling C. LC coupling D. direct coupling
Description : Which of the following statments is true of the illustrated motor controller? EL-0023 A. The low speed is used for starting the motor and when the controller automaticly shifts to High speed. B. The HOL relay ... D. If the overload relay opens for high speed the motor can still be run in low speed.
Description : The transistors in the illustrated circuit are connected using what type of coupling? EL-0051 A. RC coupling B. transformer coupling C. impedance coupling D. direct coupling
Description : The illustrated motor controller _________. EL-0023 A. is a low voltage release controller because the motor will stop when voltage falls below a certain value and automaticly start when normal voltage ... with a generator or transformer bank that is 'wye' wound with T2 connected to the neutral
Description : In replacing a defective transformer with a new one, which of the following actions must be carried out to insure proper operation of the equipment it serves? A. The secondary leads must be grounded ... magnetize it. D. The iron core must be grounded for 10 minutes to remove any residual magnetism.
Description : The transistors in the illustrated circuit are connected using what type of coupling? EL-0050 A. RC coupling B. transformer coupling C. Impedance coupling D. direct coupling
Description : When a fluorescent lamp has reached the end of its useful life, it should be replaced immediately, or the resultant flashing may _____________. A. blow the lamp's circuit breaker B. explode, ... fly in all directions C. short circuit the ballast transformer D. damage the starter and the ballast
Description : In a three-phase, open-delta connected transformer, the line current is equal to _____________. A. the phase current B. three times the phase current C. the sum of any two phase currents D. the difference of any two phase currents
Description : The hook-on AC volt-ammeter consists essentially of a split-core and a rectifiertype instrument connected to the secondary winding of a _____________. A. potential transformer B. control transformer C. current transformer D. reactance transformer
Description : Which of the listed transformer uses a single winding to produce voltage transformation? A. Stepup transformers B. Stepdown transformers C. Autotransformers D. Isolation transformers
Description : Which of the following statements is true concerning a stepdown transformer in an operating AC power circuit? A. Voltage and current will both be increased. B. Voltage and current will both be decreased C. Voltage decreases as current increases. D. Voltage increases as current decreases.
Description : What can be used to replace the exciter in the circuit shown in the illustration? EL-0101 A. A step-up transformer. B. A rectifier. C. A step-down transformer. D. An operational amplifier.
Description : In order to take a current reading with a 'clamp-on' ammeter, the instrument's jaws _________________. A. should remain open B. cannot touch the adjacent conductor C. must be fully closed D. will act as a transformer primary