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

Classify the transformers based on the construction, frequency and power.
by

1 Answer

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) Purpose: Power T/F, Distribution T/F v) Use: Instrument, Protection, Control vi) Cooling: Self-cooled, Air-cooled, Forced-air cooled, Oil-cooled, Forced-oil cooled. 

by

Related questions

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

Description : The efficiencies of transformers compared with that of electric motors of the same power are?

Last Answer : Transformers have high efficiency than the same ratted motors

Based on temperature withstanding ability, classify insulating material.

Description : Based on temperature withstanding ability, classify insulating material. 

Last Answer : class Temperature withstanding ability in 0C Materials Y 90 Cotton, silk paper and similar organic materials neither impregnated nor immersed in any oil, rubber, PVC. A 105 ... rubber compounds C Above 180  Mica, ceramics, glass, Teflon, quartz, etc. 

What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to

Description : What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to a 500 Hz (frequency) source of the same voltage:  (A) Eddy Current and Hysteresis losses will be ... Current will be too much high  (C) Transformer may start to smoke and burn  (D) No effect

Last Answer : What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to a 500 Hz (frequency) source of the same voltage:  (A) Eddy Current and Hysteresis losses will be ... will be too much high  (C) Transformer may start to smoke and burn  (D) No effect

For a 500 Hz frequency excitation, a 50 km long power line will be modeled as

Description : For a 500 Hz frequency excitation, a 50 km long power line will be modeled as

Last Answer : For a 500 Hz frequency excitation, a 50 km long power line will be modeled as long line

The device which allows reverse power flow and withstands highest switch frequency is

Description : The device which allows reverse power flow and withstands highest switch frequency is (A) GTO (B) MOSFET (C) IGBT (D) Inverter grade SCR

Last Answer : The device which allows reverse power flow and withstands highest switch frequency is MOSFET

The time period of third harmonic of power supply frequency, in milliseconds, is

Description : The time period of third harmonic of power supply frequency, in milliseconds, is (A) 20 (B) 3.33 (C) 6.66 (D) 60

Last Answer : The time period of third harmonic of power supply frequency, in milliseconds, is 6.66 

State the meaning of secondary instrument. Classify secondary instruments.

Description : State the meaning of secondary instrument. Classify secondary instruments.

Last Answer : Secondary instruments: - Gives reading directly of the quantity being measured. - Calibrated with respect to absolute instruments  Classification of Secondary instruments:  1. Depending on the ... on permissible error: i) Standard meters ii) Substandard meters iii) First grade instruments.

Classify electrical materials.

Description : Classify electrical materials.

Last Answer : Classification of electrical materials: i) Conducting Materials ii) Insulating materials iii) Magnetic materials iv) Semiconducting materials

Classify magnetic materials and explain in brief.

Description : Classify magnetic materials and explain in brief.

Last Answer : .embed-container { position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; } .embed-container iframe, .embed-container object, .embed-container embed { ... the absence of external magnetic field. Following are the ferromagnetic materials: Iron, Cobalt, Nickel.

Explain construction and working principle of single phase transformer.

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

Last Answer : A single phase transformers is an electrical device that accepts single-phase AC power and outputs single-phase AC. PRINCIPLE... The single-phase transformer works on the principle of ... and secondary windings. Thin steel laminations shall be employed to prevent power losses from the core.

74)Power transformers are generally designed to have maximum efficiency around A. No load B. Half load C. Near full load D. 10% overload

Description : 74)Power transformers are generally designed to have maximum efficiency around A. No load B. Half load C. Near full load D. 10% overload

Last Answer : C. Near full load

[23] Transformers are rated in KVA instead of KW because A. load power factor is often not known B. KVA is fixed whereas KW depends on load power factor C. Total transformer loss depends on volt ampere D. It has become customary

Description : [23] Transformers are rated in KVA instead of KW because A. load power factor is often not known B. KVA is fixed whereas KW depends on load power factor C. Total transformer loss depends on volt ampere D. It has become customary

Last Answer : C. Total transformer loss depends on volt ampere

Power transformers are generally designed to have maximum efficiency around?

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

TRANSFORMERS MCQ

Description : TRANSFORMERS MCQ

Last Answer : 101. A shell-type transformer has (a) high eddy current losses (b) reduced magnetic leakage (c) negligibly hysteresis losses (d) none of the above Ans: b 102. A transformer can have regulation closer to zero (a ... (6) much smaller (c) much higher (d) somewhat smaller (e) none of the above Ans: c

What are the schedules of maintenance done on transformers?

Description : What are the schedules of maintenance done on transformers?

Last Answer : Ans. Following are the schedules of maintenance on transformers. a. Daily maintenance. b. Monthly maintenance. c. Quarterly maintenance. d. Half yearly maintenance. e. Yearly maintenance. f. 5 Yearly maintenance.

Why a transformer requires cooling. What are the methods of cooling transformers?

Description : Why a transformer requires cooling. What are the methods of cooling transformers?

Last Answer : Ans. Transformers requires cooling as they get heated up due to various losses taking place in the transformer. (like iron of copper losses) Following are the methods of cooling of transformer. a. Natural ... . Forced oil air Natural Cooling (OFAN). d. Forced oil and forced Air cooling (OFAF).

What are the loses in Transformers, Explain?

Description : What are the loses in Transformers, Explain?

Last Answer : Ans. (1) Iron loses (2) Copper loses Iron Loss : Iron loss occurs in the transformers Iron core due to hysteresis and eddy currents taking place. They are almost fixed irrespective of ... losses in the primary and the secondary windings of the transformer which with the loading of transformer.

Which of the following connection of transformers will give highest value of secondary voltage ?

Description : Which of the following connection of transformers will give highest value of secondary voltage ? (A) Delta primary delta secondary (B) Delta primary star secondary (C) Star primary star secondary (D) Star primary delta secondary

Last Answer : Which of the following connection of transformers will give highest value of secondary voltage ? (A) Delta primary delta secondary (B) Delta primary star secondary (C) Star primary star secondary (D) Star primary delta secondary

Two transformers A and B having equal outputs and voltage ratios but unequal percentage

Description : Two transformers A and B having equal outputs and voltage ratios but unequal percentage impedances of 4 and 2 are operating in parallel. The transformer A will be overloaded by 

Last Answer : Two transformers A and B having equal outputs and voltage ratios but unequal percentage impedances of 4 and 2 are operating in parallel. The transformer A will be overloaded by 33%

Core type transformers are popular in___________.

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

Last Answer : Core type transformers are popular in High voltage applications

In a transmission line if booster transformers are to be used, preferred location will be

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 

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

The friction losses in Real Transformers are :

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

Last Answer : A

Two 3-phase transformers cannot be operated in parallel, if their :

Description : Two 3-phase transformers cannot be operated in parallel, if their :  (A) kVAs are different (B) phase sequences are different (C) % impedances are different (D) voltage ratios are different

Last Answer : Two 3-phase transformers cannot be operated in parallel, if their : phase sequences are different

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

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

Last 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

Which of the following is the advantage of using CRGO steel in transformers?

Description : Which of the following is the advantage of using CRGO steel in transformers? A) High magnetic flux density B) Low permeability C) Both A and B D) None of these

Last Answer : It definitely High Magnetic Flux Density since a crgo steel has always a more around 3% of silicon proportion among the remaining ferrite which make cold rolled grain oriented steel having high flux magnetic ... for more about the crgo core you can learn here https://nicoreindia.com/crgo-core/

Instrument transformers are?

Last Answer : Instrument transformers are potential transformers, current transformers.

Natural oil cooling is used for transformers up to a rating of?

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

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

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

Last 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.

Distribution transformers are generally designed for maximum efficiency around?

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

Two transformers do not have equal percentage impedance. This is likely to result in?

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

Last 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.

Short circuit test on transformers is conducted to determine?

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

For the parallel operation of single phase transformers it is necessary that they should have?

Last 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.

Natural air cooling is generally restricted for transformers up to?

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

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

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

Last Answer : Friction losses windage losses 

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

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

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

of what use are current and voltage transformers in protective systems

Last 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.

Why do transformers make noise?

Description : Why do transformers make noise?

Last Answer : Transformers make noise based on it out put if an transformer outputs is 400v maximum than a 398v be apply to that transformer it also make a noise because of that 

The clock frequency of an 8085 microprocessor based system is 3 MHz. What should be the minimum pulse

Description : The clock frequency of an 8085 microprocessor based system is 3 MHz. What should be the minimum pulse width of the INTR signal so that it is recognized successfully? A) 5.6 µs B) 5.7 µs C) 5.8 µs D) 5.9 µs

Last Answer : The clock frequency of an 8085 microprocessor based system is 3 MHz. What should be the minimum pulse width of the INTR signal so that it is recognized successfully? A) 5.6 µs B) 5.7 µs C) 5.8 µs D) 5.9 µs

Operating frequency of power MOSFET is higher than that of power BJT. Justify the statement.

Description : Operating frequency of power MOSFET is higher than that of power BJT. Justify the statement.

Last Answer : Power MOSFET have high turning on and turning off capability high switching speed of MOSFET is due to the high rate of change of drain voltage. The switching losses of power MOSFET ... lower frequency. Hence, operating frequency of power MOSFET is higher than that of power BJT.

Will rain water damage a building under construction?

Description : Will rain water damage a building under construction?

Last Answer : Often, yes, if you do it wrong. It's usually not a problem if the bones of the building get a bit wet before the roof goes on; things dry out easily before you install insulation and ... buildings are all metal, glass and concrete until the exterior is done, so even less problems with water.

How thick do you make the exterior and interior walls of a residence if you are using Post and Beam construction instead of standard Timber Frame?

Description : How thick do you make the exterior and interior walls of a residence if you are using Post and Beam construction instead of standard Timber Frame?

Last Answer : Post and Beam is historically 10 to 12 inches by the same. . . so wall thickness of up to 12 inches. I owned a 1720’s center chimney with post and beam.

How long have construction workers been laying sheet of plastic on the ground before laying the foundation?

Description : How long have construction workers been laying sheet of plastic on the ground before laying the foundation?

Last Answer : https://en.wikipedia.org/wiki/Vapor_barrier

How do construction cranes rise up?

Description : How do construction cranes rise up?

Last Answer : Look at rough terrain mobile crane to see if that’s what you mean.

Help with very basic construction, generalized building code info?

Description : Help with very basic construction, generalized building code info?

Last Answer : It seems to me she should have obtained a building permit before beginning, posted in full view. She should have submitted a set of plans to the appropriate engineering dept to get an approval to ... on what unbalanced fill is. http://www.doityourself.com/forum/archive/index.php/t-308617.html

How can a person improve at the job of construction?

Description : How can a person improve at the job of construction?

Last Answer : Just build things. The more you do it the better you get. The internet is full of every how-to imaginable. Also go to the clinics at Home Depot. They are constantly demonstrating tools and techniques.

How can I find out about new construction near my land?

Description : How can I find out about new construction near my land?

Last Answer : i think you go to city hall to get the actual dimensions of your property and your neighbor's property

How to make construction profitable and a house durable?

Description : How to make construction profitable and a house durable?

Last Answer : It so happened that we often make excessive demands on anything, wanting to save money and get high quality as a result. Especially in the case of building a house. Is it possible to save on ... immersed in the ground. Usually there are two of them - the method of indentation and screwing in.

What paintwork materials are used in construction?

Description : What paintwork materials are used in construction?

Last Answer : What paintwork materials are used in construction? Whatever the building material, it needs protection from external factors. Whether it be wood, concrete or metal, it doesn't matter. The ... plastered surfaces. Silicate paints are also capable of imparting good fire resistance to wood.  

Explain construction and working of AC servomotor.

Description : Explain construction and working of AC servomotor.

Last Answer : Construction of AC Servo Motor: AC servo motor is mainly composed of a stator and a rotor. Laminated stator core is usually made of silicon steel. Two phase windings are placed in the stator slots at 90 degree ... on rotor. Due to the force or torque acting on the rotor, it is set in motion.