# Use of auto-transformer is economical when the transformation ratio is?

Use of auto-transformer is economical when the transformation ratio is?

Use of auto-transformer is economical when the transformation ratio is near unity.

## Related questions

Description : Auto-transformer makes effective saving on copper and copper losses, when its transformation ratio is?

Answer : Auto-transformer makes effective saving on copper and copper losses, when its transformation ratio is approximately equal to 1.

Description : The voltage transformation ratio of a transformer is equal to the ratio of?

Answer : The voltage transformation ratio of a transformer is equal to the ratio of secondary induced e.m.f. to primary induced e.m.f.

Description : Define: 1) voltage ratio, 2) current ratio, 3) transformation ratio of transformer.

Answer : 1) Voltage ratio: The voltages in primary and secondary winding is proportional to number of turns in primary and secondary respectively. So, the voltage ratio is same as transformation ratio. V2/V1 = N2 ... as transformation ratio of transformer. It is denoted by K. K = N2/N1

Description : What is transformation ratio?

Answer : Transformation Ratio (k):- 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.

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

Answer : an autotransformer may used only as step down transformer

Description : 3kW load is supplied by an autotransformer with 0.7 transformation ratio. Conductively transferred power from primary to secondary is (A) 2.1 kW (B) 0.9 kW (C) 4.29 kW (D) 3 kW

Answer : 3kW load is supplied by an autotransformer with 0.7 transformation ratio. Conductively transferred power from primary to secondary is 2.1 kW

Answer : For a consumer the most economical power factor is generally 0.95 lagging .

Description : What is the use of transformer?

Answer : The use of transformer  is to do lower or raise  the voltage or currents in an electrical  circuit.  That's quite so simple.

Description : Source transformation problem solution

Description : Find the current through 4 ohm resistor by source transformation

Description : Source transformation Replace the circuit with voltage source in series with a single resistor

Answer : Source transformation Replace the circuit with voltage source in series with a single resistor

Description : Source transformation voltage source to current source and vice versa

Description : Wye Delta Transformation

Answer : Wye Delta Transformation 1 : https://youtu.be/mPKeczDWZCo Wye Delta Transformation 2 : https://youtu.be/k80VbHI-wwg Wye Delta Transformation 3 : https://youtu.be/6cnwj15uw5M Wye Delta Transformation ... 8 : https://youtu.be/knRb5UW1404 Wye Delta Transformation 9 : https://youtu.be/JBwHKBJ08WM

Description : Explain space vector transformation and space vector switching with the help of diagram. What are the advantages of SVM?

Description : An auto transformer having a transformation ratio of 0.8 supplies a load of 10 kW. The power transferred inductively from the primary to secondary is (a) 2 kW (b) 4 kW (c) 8 kW (d) 10 kW

Answer : The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is 0.5.

Answer : The stator of phase shifting transformer for use in conjunction with an A.C. potentiometer usually has a two-phase winding.

Description : What is the use of Buchholz relay in transformer?

Answer : This is a transformer that is used to step up and down current.

Answer : Series capacitors on transmission lines are of little use when the load VAR requirement is small.

Description : In otto cycle compression ratio is 8. Calculate air standard efficiency. Will it be grater than Carnot Cycle ? Justify your answer.

Answer : No, the Otto cycle efficiency 56.47% will always be lower than Carnot cycle efficiency. Justification: Carnot theorem states that keeping operating conditions same, Carnot engine is more efficient than any other engine. So, Otto cycle efficiency is lower than Carnot cycle efficiency.

Description : Graph indicating changes in pollutants level w.r.t air fuel ratio

Answer : Graph indicating changes in pollutants level w.r.t air fuel ratio

Description : Compressor pressure ratio (CPR)

Answer : Compressor pressure ratio (CPR), is the ratio of the air total pressure exiting the compressor to the air pressure entering the compressor. This number is always greater than 1.0.

Description : SEER: Seasonal Energy Efficiency Ratio (SEER)

Answer : SEER: Seasonal Energy Efficiency Ratio (SEER), is most commonly used to measure the efficiency of a central air conditioner. The higher the SEER, the more efficient the system OR It is the ... the ratio of total capacity to the total KW energy usage at specific humidity and temperature condition.

Description : Voltage ratio

Description : Turns ratio

Description : Impedance ratio

Description : Current ratio

Description : The ratio of the width to the height of the picture frame is called as A) Rastar B) Aspect Ratio C) Length Ratio D) Efficiency

Answer : The ratio of the width to the height of the picture frame is called as Aspect Ratio

Description : If the fault current is 6000 A, the relay plug setting is 150% and the CT ratio is 400/5, the plug setting multiplier will be

Answer : If the fault current is 6000 A, the relay plug setting is 150% and the CT ratio is 400/5, the plug setting multiplier will be 10

Description : Given a unity feedback system with G(s)=k/s (s+4), the value of k for damping ratio of 0.5 is

Answer : Given a unity feedback system with G(s)=k/s (s+4), the value of k for damping ratio of 0.5 is 16

Description : A dc chopper is fed from a constant voltage mains the duty ratio of chopper is progressively increased while the chopper feeds an RL load. The per unit current ripple would  (1) increase progressively  (2 ... 0.5 and then increase  (4) increase to a maximum value at α = 0.5 and then decrease

Answer : A dc chopper is fed from a constant voltage mains the duty ratio of chopper is progressively increased while the chopper feeds an RL load. The per unit current ripple would increase to a maximum value at α = 0.5 and then decrease

Description : If Poisson's ratio of a resistance wire strain gauge is 1.8, then neglecting piezo-resistive effects, its Gauge factor is :  (A) 2.8 (B) 2.6 (C) 4.6 (D) 3.6

Answer : If Poisson's ratio of a resistance wire strain gauge is 1.8, then neglecting piezo-resistive effects, its Gauge factor is : 4.6

Description : The ratio of full -load volt-amperes to short-circuit volt-amperes is equal to :

Answer : The ratio of full -load volt-amperes to short-circuit volt-amperes is equal to : Z (p.u)

Description : Specific energy consumption of an electric train is the ratio between (A) Specific energy output at driving wheels and efficiency of the traction motor (B) Specific energy output at driving wheels ... (D) Specific energy output at driving wheels and efficiency of the (motor + transmission gear)

Answer : Specific energy consumption of an electric train is the ratio between Specific energy output at driving wheels and efficiency of the (motor + transmission gear)

Description : Ratio of the rotor reactance X to the rotor resistance R for a two-phase servo motor (A) is equal to that of a normal induction motor (B) is less than that of a normal induction motor (C) ... than that of a normal induction motor (D) may be less or greater than that of a normal induction motor

Description : The Eb/V ratio of a d.c. motor is an indication of its?

Answer : The Eb/V ratio of a d.c. motor is an indication of its efficiency.

Description : The ratio of mass of proton to that of electron is nearly?

Answer : The ratio of mass of proton to that of electron is nearly 1840.

Description : Two bulbs of 500 W and 200 W rated at 250 V will have resistance ratio as?

Answer : Two bulbs of 500 W and 200 W rated at 250 V will have resistance ratio as 2 : 5.

Description : The ratio of active power to apparent power is known as____ factor.

Answer : The ratio of active power to apparent power is known as power factor.

Answer : The form factor is the ratio of r.m.s. value to average value.

Description : The ratio of limiting friction and normal reaction is known as?

Answer : The ratio of limiting friction and normal reaction is known as coefficient of friction.

Answer : The ratio of starting torque to full-load torque is least in case of shunt motors.

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

Description : Find power delivered by voltage source

Answer : Find power delivered by voltage source

Description : Explain construction and working of single phase Auto transformer.

Answer : Construction of single phase auto transformer: (i) It has only one winding wound on a laminated circular magnetic core. (ii) The core is made of silicon steel stampings. (iii) The two terminals of the ... help of handle. 5) The same transformer can be used as step-up or step down auto-transformer

Description : State the use of synchroscope.

Answer : Use of Synchroscope: The synchroscope is used to determine the exact instant of switching required to connect the alternators in parallel or put an alternator in parallel with the infinite bus. ... idea of the faster or slower machine to make adjustments in speed of alternators for synchronising.

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.

Description : Use phasors to find

Answer : Use phasors to find

Description : State the use of:- (i) Clip-on-ammeter (ii) Phase sequence indicator

Answer : (i) Clip-on-ammeter: used for measurement of current in cables/lines in live conditions without disconnecting them.  (ii) Phase sequence indicator: To determine /find the phase sequence of 3 phase supply.

Description : An _____________is a network of electrical components used to supply, transfer and use electric power:  (A) Electric power system (B) Electric power (C) All of the above (D) None of the above

Answer : An Electric power system is a network of electrical components used to supply, transfer and use electric power.

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