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What is considered low voltage and high voltage?

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Description : Step-down transformer converts high voltage and low current into:  (A) How voltage and high current (B) High voltage and low current (C) Low voltage and high current (D) None of the above

Answer : Step-down transformer converts high voltage and low current into: Low voltage and high current

Description : What is the difference between a line voltage and low voltage control system?

Description : What is the definition of extra low voltage?

Answer : Extra-low voltage (ELV) is an electricity supply voltage in a range which carries a low risk of dangerous electrical shock.

Description : What is Extra High Voltage?

Description : What are the advantages of high voltage transmission?

Answer : Advantages:  1. As Transmission voltage increases, current decreases. 2. As current decreases, cross section of conductor decreases. 3. As cross section of conductor decreases ... line increases  12. As transmission voltage increases power handling capacity of transmission line increases 

Description : What is a high voltage test?

Description : Name two methods for measurement of low, medium and high resistance. Give one advantage and one limitation of V- I method.

Answer : Methods for measurement of low resistance:  1. Ammeter voltmeter method  2. Kelvin's bridge method  3. Ohm meter method  4. Potentiometer method  5. Digital/analog multi-meter ... must be infinity for perfectly accurate measurement which is not possible.  2. Connection errors.

Description : Why high voltage test is done?

Description : Why high voltage can reduce power loss?

Answer : when voltage has increased due to reduced current flow, thus power loss given by ( I^2R) will be low due to reduced current(I^2) provided that resistance (R) is constant.

Description : Why high voltage is used in power transmission?

Answer : The primary reason that power is transmitted at high voltages is to increase efficiency. ... The lower current that accompanies high voltage transmissionreduces resistance in the conductors aselectricity flows ... This means that thin, light-weight wires can beused in long-distance transmission.

Description : Which of the following is the least expensive protection for over current in low voltage system?  (A) Rewireable fuse (B) Isolator (C) Oil Circuit breaker (D) Air break circuit breaker

Answer : Which of the following is the least expensive protection for over current in low voltage system?  (A) Rewireable fuse (B) Isolator (C) Oil Circuit breaker (D) Air break circuit breaker

Description : What is meant by extra high voltage transmission?

Answer : HT & LT  two types transmission in industrial line 

Description : Limitation and application of High Voltage DC (HVDC)

Answer : Limitation and application of High Voltage DC (HVDC) :  Limitation:- 1) It is difficult to step up and step down DC voltage like AC voltage. 2) Special cooling ... conventional/non-conventional) 12) Increasing existing grid utilization. 13) Interconnection of different grids or networks

Description : State the advantages of use of high voltage in transmission of Electric power. 

Answer : Advantages: 1. As Transmission voltage increases, current decreases. 2. As current decreases, cross section of conductor decreases. 3. As cross section of conductor decreases, its ... high voltage transmission line, successful interconnection of transmission line is possible than low voltage. 

Answer : For measurements on high voltage capacitors, the suitable bridge is Schering bridge.

Answer : The contacts of high voltage switches used in power system are submerged in oil. The main purpose of the oil is to extinguish the arc.

Description : Why is it cheaper to transmit electrical energy at high voltage?

Answer : Because of the electrical energy was step upped by transformers the transformer have high efficiency than the electric energy is cheaper

Answer : yes High Voltage side of Transformer winding have more number of turns. and low voltage side of Transformer winding have less number of turns.

Description : What is the difference between line and phase voltage?

Answer : Line voltage  is  voltage  between two  phases R &Y  (415 v)  while  phase  voltage  is  the  voltage  between  one  phase and  a neutral  B &  N   (240 v).

Description : What is meant by flash over voltage?

Description : What is dielectric withstand voltage?

Description : What is impulse voltage of transformer?

Description : State the range for low and medium resistance.

Answer : Low resistances: less than 1 ohm.  Medium resistances: 1 ohm to 0.1 Mega ohm. 

Description : In voltage source converter based HVDC transmission system the active power is controlled by changing (A) phase angle of the converter ac input voltage (B) supply frequency of the converter ac input voltage (C) magnitude of the converter ac input voltage (D) DC voltage at the inverter terminals

Answer : In voltage source converter based HVDC transmission system the active power is controlled by changing phase angle of the converter ac input voltage

Description : How do you fix voltage drop?

Description : Why does increase in current mean a decrease in voltage?

Answer : This is because current flows from high potential to low potential to bring the two diffrent potential to unity , thus  a reduced potential (voltage)

Description : Name the method used to measure following resistances:- (i) Low resistance (ii) Medium resistance (iii) Insulation resistance (iv) Earth resistance.

Answer : Following are the methods used to measure resistances:-  (i) Low resistance: 1.Voltmeter-Ammeter Method 2. Kelvin's Double bridge Method  (ii) Medium resistance: 1.Voltmeter-Ammeter Method 2. ... of Charge Method  (iv) Earth resistance : 1. Fall of Potential Method 2. Earth tester

Description : In a 741 Op-Amp, there is 20 dB/decade fall-off starting at a relatively low frequency. This is due to the (A) applied load (B) internal compensation (C) impedance of the source (D) power dissipation in the chip

Answer : In a 741 Op-Amp, there is 20 dB/decade fall-off starting at a relatively low frequency. This is due to the internal compensation

Description : Accurate measurement of very low resistances is possible with (A) Megger (B) Wheatstone Bridge (C) Kelvin’s Double Bridge (D) Wagner’s Earthing Device

Answer : Accurate measurement of very low resistances is possible with Kelvin’s Double Bridge

Answer : Turbine used for low head is Kaplan turbine.

Description : At very low frequencies a series R-C circuit behaves as almost purely?

Answer : At very low frequencies a series R-C circuit behaves as almost purely capacitive.

Description : In an AC. circuit, a low value of kVAR compared with kW indicates?

Answer : In an AC. circuit, a low value of kVAR compared with kW indicates high power factor.

Answer : In a low power factor wattmeter the pressure coil is connected to the load side of the current coil.

Answer : A synchronous machine with low value of short-circuit ratio has lower stability limit.

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

Answer : A low utilization factor for a plant indicates that plant is used for stand by purpose.

Answer : To protect most of the electrical equipment handling low power, the types of relays used are thermocouple, electronic and bimetallic.

Description : The efficiency of a transformer, under heavy loads, is comparatively low because?

Answer : The efficiency of a transformer, under heavy loads, is comparatively low because copper loss becomes high in proportion to the output.

Description : At which time power factor of the induction motor is low?

Answer : The power factor of the inducction motor is low at the time of starting as compare to while the induction motor is running.

Description : write short notes on Low-pass filter.

Answer : low-pass filter (1) filter exhibiting frequency selective characteristic that allows low-frequency components of an input signal to pass from filter input to output unattenuated all high-frequency components are ... the bandwidth of the filter. A filter whose impulse response is a low-pass signal.

Answer : MOSFET have high current losses due to High on state resistance. Hence MOSFET is used for low power applications.

Description : What can cause high amperage on a motor?

Answer : High  amperage  can  result  in  a motor  when the  amount  of  load  increases. when  load  increases  , it  reduces  the  rotor  speed which  increases  the  slip  at  constant  synchronous  speed ... ,  as  a  result  more  current  shall  have  been  drawn  to  maintain  the  additional  load.

Description : What is a high tension power line?

Answer : High tension power line is a high voltage of 115 kv and power line is underground transimissio used by urbun areas

Description : What is the advantage of high power factor?

Answer : Reduced copper losses Smaller conductor size Improve voltage regulation Increase system capability Less energy bill

Answer : Buses, trains, trolleys, hoists, cranes require high starting torque and therefore make use of D.C. series motor.

Description : Which of the following thyristors can be used for high frequency of operation? A) TRIAC B) DIAC C) SCR D) GTO 

Answer : Which of the following thyristors can be used for high frequency of operation? A) TRIAC B) DIAC C) SCR D) GTO 

Description : Which of the following circuit breakers has high reliability & minimum maintenance?  (A) Bulk oil type CB (B) Air blast CB (C) Vacuum CB (D) Sulphur hexafluoride CB 

Answer : Which of the following circuit breakers has high reliability & minimum maintenance?  (A) Bulk oil type CB (B) Air blast CB (C) Vacuum CB (D) Sulphur hexafluoride CB 

Description : The number of cycles in which a high speed circuit breaker can complete its operation is  (A) 3 to 8 (B) 10 to 18 (C) 20 to 30 (D) 40 to 50

Answer : The number of cycles in which a high speed circuit breaker can complete its operation is 3 to 8

Description : Which type of ADC gives high resolution?

Answer : Sigma Delta, successive approximation and integrating type analogue to digital converter gives very high resolution but they have slower speed.

Description : At very high temperatures, extrinsic semiconductor becomes intrinsic semiconductor because (A) Of drive in diffusion of dopants & carriers. (B) Band to band transition dominates impurity ionization. (C) ... band to band transition. (D) Band to band transition is balanced by impurity ionisation.

Answer : At very high temperatures, extrinsic semiconductor becomes intrinsic semiconductor because Impurity ionization dominates band to band transition.

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