search
person
The efficiencies of transformers compared with that of electric motors of the same power are?

2 Answers

The efficiencies of transformers compared with that of electric motors of the same power are somewhat smaller.
thumb_up_alt 0 like thumb_down_alt 0 dislike
Transformers have high efficiency than the same ratted motors
thumb_up_alt 0 like thumb_down_alt 0 dislike

Related questions

Description : Losses which occur in rotating electric machines and do not occur in transformers are?

Answer : Friction losses windage losses 

Description : State which electric motors are generally used in electro agro systems with reason.

Answer : 1) 3 phase induction motor is used in electro agro system for water pumping from wells as 3 phase ac supply is easily available, cost of induction motor is less, maintenance free being rugged ... as 1 phase ac supply is easily available for domestic purpose, repair is simple and easily available.

Description : Suggest electric motors for i) traction ii) crane iii) lathe machine iv) domestic fan.

Answer : i) Traction :- DC Series motor  ii) Crane :- DC Series motor  iii) Lathe machine :- 3 phase Induction motor or DC shunt motor  iv) Domestic fan :- 1 phase induction motor

Answer : The standard full-load power factor ratings for synchronous motors are unity or 0.8 leading.

Description : Classify the transformers based on the construction, frequency and power.

Answer : Classification of Transformer Based On: i) Construction: Shell type, Core type, Berry type ii) Change in voltage level: Step-Up, Step-Down, iii) Number of phases: Single phase, Three phase iv) ... Control vi) Cooling: Self-cooled, Air-cooled, Forced-air cooled, Oil-cooled, Forced-oil cooled. 

Answer : For power factor correction, synchronous motors operate at no-load and greatly over-excited fields.

Answer : Power transformers are generally designed to have maximum efficiency around near full-load.

Description : State elements of diesel electric power plant with their functions. 

Answer : Elements of Diesel Power Plant with their function):   1) Diesel Engine: - This is the main component of the P.P. which develops mechanical power. 2) Engine air intake system: - Air ... fuel as per requirement. 10) Alternator: - Its function is to convert mechanical power into electrical power.

Description : "Hydro electric power station are not perennial power station". Justify.

Answer : Justification: The water utilized by the hydro power plants comes mostly from storage dams/reservoirs which get filled up during the monsoon rainy season. Such reservoirs are utilized for supplying ... are important. Hence "Hydro electric power stations are not perennial power station" 

Description : what are the three different types of Electric power?

Answer : Real,reactive,apparent power

Answer : Necessary conditions required to be satisfied in order to ensure successful parallel operation of single phase transformers:  1. Only transformers having the same phase displacement between primary and secondary ... . 7. The phase sequence must be followed strictly on HV and LV side connection.

Description : Electric Power

Answer : Electric Power

Description : Options: A) WATT B) AMPERE C) VOLTS D) OHM

Answer : Correct Answer: A) WATT

Description : Electric power formula

Answer : Electric power formula

Description : Explain starting system in diesel electric power plant.

Answer : Starting system in Diesel Electric Power Plant: It includes Storage battery, compressed air tanks, self-starter etc. The purpose of engine starting system is to rotate the engine initially while ... as Ammeters, Voltmeters, Wattmeters, Thermometers, Pressure gauges, Visible and audible alarm etc.

Description : Explain fuel system and air intake system in diesel electric power plant.

Answer : Fuel system and air intake system in diesel electric power plant :  Fuel system: It consists of storage tank, strainers, fuel transfer pump and all day fuel tank. The fuel oil is supplied ... Filters are provided to remove dust particles from air which may act as abrasive in the engine cylinder.

Description : State any four advantages and four disadvantages of diesel electric power plant. 

Answer : Advantages of Diesel electric power plant:- 1) The design and layout of Diesel electric power plant is simple. 2) It requires less space. 3) Time required for complete erection of diesel power plant is less ... . 9) The useful life is very short. 10) Availability of fuel in future may be limited.

Description : List out the four applications of diesel electric power plant.

Answer : Applications of Diesel Power Plant: 1. It can be used as a standby (emergency) power plant to maintain continuity of supply. (Incase failure of main supply like hospital, Telephone exchange Radio stations, ... 10. Diesel plants are widely used for generating power ranging from 100 to 5,000 H.P.

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.

Description : The storage battery generally used in electric power stations is  (1) zinc carbon battery (2) lead acid battery (3) nickel cadmium battery (4) lithium -ion battery

Answer : The storage battery generally used in electric power stations is lead acid battery 

Description : Power factor of electric bulb is?

Answer : Power factor of electric bulb is unity.

Answer : Power for lighting in passanger coach, in a long distance electric train, is provided through individual generator of bogie and batteries.

Answer : In a steam locomotive electric power is provided through small turbo-generator.

Answer : The power mentioned on the name plate of an electric motor indicates the output power available at the shaft.

Description : What is electric power generation transmission and distribution?

Answer : Generation: it wrong word at here.because it is no generation it is conversion of one form of energy into electrical form.it may by using any type of energy. Transmission is just to ... place to other by providing some modifications And distribution means use of this energy for any purpose.

Description : If the percentage impedances of the two transformers working in parallel are different, then?

Answer : If the percentage impedances of the two transformers working in parallel are different, then parallel operation will still be possible, but the power factors at which the two transformers operate will be different from the power factor of the common load.

Answer : Distribution transformers are generally designed for maximum efficiency around 50% load.

Description : Choose the correct order of electric discharge lamps in their increasing order of efficiencies (lumens/watt) :  (A) Sodium vapour lamp, Mercury vapour lamp, Neon lamp  (B) Neon lamp, Sodium vapour ... Mercury vapour lamp, Sodium vapour lamp  (D) Mercury vapour lamp, Sodium vapour lamp, Neon lamp

Answer : Choose the correct order of electric discharge lamps in their increasing order of efficiencies (lumens/watt) :  (A) Sodium vapour lamp, Mercury vapour lamp, Neon lamp  (B) Neon lamp, Sodium ... Mercury vapour lamp, Sodium vapour lamp  (D) Mercury vapour lamp, Sodium vapour lamp, Neon lamp

Answer : Natural oil cooling is used for transformers up to a rating of 3000 kVA.

Description : Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in?

Answer : Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in loading of the transformers not in proportion to their kVA ratings.

Answer : Short circuit test on transformers is conducted to determine copper losses.

Answer : Natural air cooling is generally restricted for transformers up to 1.5 MVA .

Description : The efficiency of two identical transformers under load conditions can be determined by?

Answer : The efficiency of two identical transformers under load conditions can be determined by back-to-back test.

Description : 3 phase motor  42 hp  same ratting two motors  but pole change 2 and 4 pole   tell me difference amp of both motors

Answer : Starters are used with D.C. motors because to restrict armature current as there is no back e.m.f. while starting.

Answer : Much higher efficiency of transformer compared with that of electrical motors of the same power.

Description : An additional condition for parallel operation of three-phase transformers over single-phase transformers is that

Answer : An additional condition for parallel operation of three-phase transformers over single-phase transformers is that the transformers should belong to the same vector group

Answer : A common method of cooling a power transformer is oil cooling.

Answer : In a capacitor start and run motors the function of the running capacitor in series with the auxiliary winding is to improve power factor.

Description : Core type transformers are popular in___________.  (A) High voltage applications (B) Low voltage applications (C) All of the above (D) None of the above

Answer : Core type transformers are popular in High voltage applications

Description : In a transmission line if booster transformers are to be used, preferred location will be  (A) At the receiving end (B) At the sending end (C) At the intermediate point (D) Anywhere in the line 

Answer : In a transmission line if booster transformers are to be used, preferred location will be At the intermediate point

Description : The friction losses in Real Transformers are :  (A) 0% (B) 5% (C) 25% (D) 50%

Answer : A

Answer : Instrument transformers are potential transformers, current transformers.

Answer : Current transformers (CT) : Current transformer (CT) actually step down the high current to low current for the operation of relays. Current transformer is use for measurement of ... use for relay. This is about potential transformer.

Description : Why are DC motors used in trains and not AC motors ?

Answer : The reason is torque. torque is inversely proportional to speed..i.e when th knowe train comes to rest position to motion.. initial speed is zero..so it requires high starting torque for ... current will flow through field and armature coils then maximum torque is available at the intial condition.

Description : What are the factors to be considered while selection of motors for different drives?

Answer : Following Factors are considered while selecting electric drive (Motor) for particular application:  Factors to be considered for selection of Electrical Drives:  1) Nature of Supply:- Whether supply ... , load equalization 7) Cost: - Capital, Running and maintenance cost should be less.  

Description : Stepper motors are used in  (1) printers (2) lifts (3) amplifiers (4) oscillators

Answer : Stepper motors are used in printers 

Description : Slot harmonics are reduced in induction motors by using (A) fractional-pitch windings (B) fractional-slot windings (C) integral-slot windings (D) distributed windings

Answer : Slot harmonics are reduced in induction motors by using fractional-slot windings

← Prev Question Next Question →
editChoose topic
...