Description : Why OC test is generally performed on LV side of a transformer?
Last Answer : The high-voltage side is generally kept open because the current in high-voltage winding is less compared to that on low-voltage winding.The LV side has higher current so that maximum no load current can be measured.
Description : Why SC test is generally performed on HV side of a transformer?
Last Answer : The rated current is less on HV side. This will also permit to use ammeter and wattmeter of lower current range.
Description : Why the tap changers are always connected to HV side of the transformer?
Last Answer : During tap changing action the load current has to be shifted from one tap to another tap. In case HV wining the load current will be less. Hence lesser arcing will take place.
Description : Why REF is now is used for HV side also in GT/SUT?
Last Answer : The E/F setting of differential is poor.
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 : A 400/200 volts transformer has pu impedance of 0.05. The HV side voltage required to circulate full load current during short circuit test is
Last Answer : A 400/200 volts transformer has pu impedance of 0.05. The HV side voltage required to circulate full load current during short circuit test is 20 V
Description : What are the protections used in Class III & Class IV 415 V LV side?
Last Answer : Class III 415 V LV side 1. 51 (inverse over current) 2. 50 (instantaneous over current) 3. 27 (under voltage) 4. 51N (earth fault) 5. 64 (REF) Class IV 415 V LV side 1. 51 RYB (inverse over current) 2. 51N (earth fault)
Description : Why REF is provided in the LV side of SUT and UT?
Last Answer : The LV sides of the two transformers are earthed through the resistance. This will limit the flow of current in case of LV earth fault. Hence the differential protection may not act for a LV earth fault. Hence ref protection is provided.
Description : Why the tapings are placed on HV side?
Last Answer : 1.A fine voltage regulation is possible with hV side as it has large number of turns. 2.LV side carries large current 3. HV side is placed outside so its feasible 4. In case of step ... large no. of turns the flux and flux density decreases. Hence core losses decreases results in higher efficiency.
Description : Voltage failure of an AC generator may be caused by ____________. A. failure of the exciter generator B. a tripped bus circuit breaker C. high mica segments on the stator bus bar D. excessive prime mover speed
Last Answer : Answer: A
Description : Two paralleled alternators are operating near rated load. If one trips out mechanically, which of the listed actions should be taken FIRST? A. Restart the tripped machine immediately. B. Strip the board ... circuits. C. Start the emergency generator. D. Transfer all vital loads to the emergency bus.
Last Answer : Answer: B
Description : How will a molded-case circuit breaker react after it has tripped, as a result of an overloaded circuit? A. The breaker will trip again if immediately reset. B. The breaker handle will lock in ... down. D. The breaker handle cannot be moved to the OFF position until the thermal element cools down.
Description : When the operating handle of a molded case circuit breaker is in the mid-position, it indicates the circuit breaker is _____________. A. in the 'opened' position B. in the 'closed' position C. tripped D. reset
Last Answer : Answer: C
Description : You can determine if a circuit breaker is tripped by ______. A. examining the position of the handle B. checking for the warm breaker C. looking for a burned-out link D. looking for the tripped breaker light
Description : When the operating handle of a molded-case circuit breaker is in the mid-position, the circuit breaker is indicated as being ____________. A. in the 'closed' position B. in the 'opened' position C. tripped D. reset
Description : You can determine if a circuit breaker has tripped by ________________. A. examining the position of the handle B. checking for which of the breakers is warm C. looking for a burned-out link D. all of the above
Description : When the operating handle of a molded-case circuit breaker is in the mid-position, this indicates that the circuit breaker is _____________. A. on B. off C. reset D. tripped
Last Answer : Answer: D
Description : On a vessel with turbo-electric drive, which of the following conditions would indicate that the propulsion motor had dropped out of synchronization with the propulsion generator? A. Excessive ... Tripped main motor interlocks C. Overheated crosstie busses D. Closed contact in the field circuits
Description : As shown in the illustration, once the "LV" relay is energized for operation, what contacts must remain closed to maintain the "LV" relay energized when the control lever is moved away from the "off" or "stop" ... . B. Reset contacts. C. Upper set of "LVa" contacts. D. Lower set of "LVa" contacts.
Description : As shown in the illustration, what is responsible for maintaining the "LV" relay energized when the master switch handle is moved away from the "off" position? EL-0102 A. "DBa" contact. B. Reset contacts. C. Upper set of "LVa" contacts. D. Lower set of "LVa" contacts.
Description : When the master switch for the winch shown in the illustration is in the 'off' position, and the line & safe switches are closed, which of the listed relays should be energized? EL-0102 A. 'DB' & '2T' B. 'DB' & '4M' C. 'FR-B.O.' & 'LV' D. '1M' & '1A'
Description : For LV applications (below 1 kV), ______________ cables are used. (A) Paper insulated. (B) Plastic. (C) Single core cables. (D) Oil filled.
Last Answer : Ans: C For low voltage applications single core cables are suitable.
Description : Mention the various tests carried out in a circuit breaker at HV labs.
Last Answer : Short circuit tests, Synthetic tests& direct tests.
Description : What is the purpose of HV / leakage current test on stator?
Last Answer : This is to find out weakness in the stator winding. If the ambient conditions are right, and the insulation is weak, the leakage current will increase non-linearly. The record of voltage ... current. In HV test starting leakage current should be more than switching off current in μ Amps.
Description : What is the DC HV test voltage range?
Last Answer : 1.7* 1.5* rated voltage.
Description : Why not high resistance for earth fault than using grounding transformer & resistor 0.45 ohms?
Last Answer : It is mechanically unwide. Difficult to manufacture.
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 : If we give 2334 A, 540V on Primary side of 1.125 MVA step up transformer, then what will be the Secondary Current, If Secondary Voltage=11 KV?
Last Answer : A. As we know the Voltage & current relation for transformer-V1/V2 = I2/I1 We Know, VI= 540 V; V2=11KV or 11000 V; I1= 2334 Amps. By putting these value on Relation540/11000= I2/2334 So,I2 = 114.5 Amps
Description : In a Tap changing transformer on which side is the tap connected, primary side or secondary side?
Last Answer : A. Tapings are always connected to high voltage winding side, because of low current. If we connect tapings to low voltage side, sparks will produce while tap changing operation due to high current.
Last Answer : As we know the Voltage & current relation for transformer-V1/V2 = I2/I1 We Know, VI= 540 V; V2=11KV or 11000 V; I1= 2334 Amps. By putting these value on Relation540/11000= I2/2334 So,I2 = 114.5 Amps
Description : In a three phase transformer, if the primary side is connected in star and secondary side is connected in delta, what is the angle difference between phase voltage in the two cases. (A) delta side lags by -30°. (B) star side lags by -30°. (C) delta side leads by 30°. (D) star side leads by -30°.
Last Answer : Ans: C This is vector group and has +30° displacement. Therefore, delta side leads by +30°.
Description : Give the details of switchyard 220 kV CB, Isolator, CT, CVT and lightning arrestor.
Last Answer : 220 kV SF6 Circuit Breaker 1. Make - ABB 2. Air pressure blocking a. Close Block - 17.3 bar. b. Open block - 16.7 bar. c. Auto reclose block - 19 bar. 3. SF6 pressure block a. Alarm - 5. ... , storage and erection. Rated voltage : 216 kV rms. Operating voltage : 184 kV rms.
Description : What are the characteristics of CB, OLR and HRC Fuse?
Last Answer : When CB is used the CB characteristics should be below the fuse, because the CB should operate first and then fuse. Not vice-versa. Because CB is the main protection or main breaking device.
Description : For interrupting capacitive currents which Circuit Breaker (CB) is used a) SF6 CB b) Oil CB c) Vacuum CB d) Air blast CB
Last Answer : Ans: Vacuum CB
Description : Why 2 types of earth fault relays in 6.6 kV side of transformers?
Last Answer : I – Trips 6.6 kV breakers only. It gives primary protection for 6.6 kV bus bars. I1 – Trips the both HT and LT breakers. It acts as a backup to ref and also acts as backup to bus bar earthfault relay.
Description : The side AB of a parallelogram ABCD is produced to any point P. A line through A and parallel to CP meets CB produced at Q, then parallelogram PBQR is completed (see figure). -Maths 9th
Last Answer : Join AC and QP, also it is given that AQ || CP ∴ △ACQ and △APQ are on the same base AQ and lie between the same parallels AQ || CP. ∴ ar(△ACQ) = ar(△APQ) or ar(△ABC) + ar(△ABQ) = ar(△BPQ) + ar(△ABQ) or ar(△ABC) = ar( △BPQ) or 1/2 ar(||gm ABCD) = 1/2 ar(||gm PBQR) or ar(||gm ABCD) = ar(||gm PBQR)
Description : Will rotor earth fault relay operate for earth fault in main exciter winding or RCU Diode Bridge also?
Last Answer : Yes.
Description : Is he ran down stairs and nearly tripped over his sister's red bag an adjective?
Last Answer : The word red is an adjective. It describes something that is anoun. Color, size, shape, taste, texture- all are adjectives.
Description : Are there any dungeons and dragons games that focus on creating a character from lv 0 to level 1?
Last Answer : Do you perchance mean role-playing games rather than Dungeons & Dragons specifically? If so, then, maybe you mean what is generally called lifepath character generation? That is, systems where you ... they enter play? If so, then yes. Perhaps the first such published RPG system was Traveller.
Description : How do you play a lv 10 diviner in Dungeons & Dragons?
Last Answer : D&D isn’t always about battle. Sometimes it’s about politics. Or adventure. There’s much more to it than just stat grinding and dungeon crawls.
Description : What is the atomic number of Lv ?
Last Answer : The atomic number of Lv is 116
Description : What is the full form of LV ?
Last Answer : Full Variety of LV.
Description : What is the full form of 'HV' ? -How To ?
Last Answer : The full form of 'HV' is High Voltage
Description : I hv 300 oman baisa where cn I change it plzz?
Last Answer : Western Asia
Description : In the following reaction: `ZnS+O_(2)overset(Delta)rarrA+ZnO` `4HCl+O_(2)overset(CuCl_(2))rarrB+2H_(2)O` `A+B overset(hv)rarrC` Then A, B and C are:
Last Answer : In the following reaction: `ZnS+O_(2)overset(Delta)rarrA+ZnO` `4HCl+O_(2)overset(CuCl_(2))rarrB+2H_(2)O` ` ... SOCl_(2)` D. `SO_(3),HClO_(3),HClO_(4)`
Description : De Broglie equation is (a) h/mv = 1 (b) E1 – E2 = hv (c) C = 1v (d) n1 = 2d sin q
Last Answer : Ans:(a)
Description : The de Broglie equation is (a) h/mv = 1 (b) hv = E2 - E1 (c) n 1 = 2d sin (d) c = hv
Description : The unity of Planck's constant 'h' in the equation, E = hv is (A) J/s (B) J.S (C) J/kmol (D) kmol/J
Last Answer : (B) J.S
Description : The probability of a photon ionizing an atom or molecule is maximum when (hv-eVi) is as small as: a. 0.5 b. 1.5 c. 3.5 d. 10
Last Answer : The probability of a photon ionizing an atom or molecule is maximum when (hv-eVi) is as small as: a. 0.5 b. 1.5 c. 3.5 d. 10