Why noise of motor is produced? How it can be reduced?

Why noise of motor is produced? How it can be reduced?

by

2 Answers

Answer :

Noise of motor is produced due to:- 1. Vibration 2. Bad foundation 3. Friction 4. Magnetic pulsation


Noise of motor can be reduced by – 1. Motor is mounted on cushion such as rubber pad instead of direct mounting on concrete foundation. 2. Motor can be mounted on spring so that it can absorb all the vibrating frequency. 3. By proper maintenance i.e. if bearings are worn out then replace it. 4. Lubrication must be done regularly. 5. Electrical connection to motor should be given through PVC flexible pipe instead of metal flexible pipe. 6. By connecting condenser of 0.1 to 0.25 microfarad across live and motor frame (earth) which will reduce magnetic pulsation. Also it will reduce radio interference

by

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 { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }
by

Related questions

Noise produced by cooling fans (employed in air cooled heat exchangers or cooling tower) is mainly caused due to the turbulence created by blade passage through air. It can be reduced by use of a slower fan (A) With greater number of blades (B) Of increased diameter (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Noise produced by cooling fans (employed in air cooled heat exchangers or cooling tower) is mainly caused due to the turbulence created by blade passage through air. It can be reduced by use of a slower fan (A) With greater ... (B) Of increased diameter (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

High noise levels produced during operation of fans and compressors can be reduced by using (A) Mufflers (silencers) (B) Acoustic absorbent (C) Lagging of noisy duct (D) None of these

Description : High noise levels produced during operation of fans and compressors can be reduced by using (A) Mufflers (silencers) (B) Acoustic absorbent (C) Lagging of noisy duct (D) None of these

Last Answer : (A) Mufflers (silencers)

Reduction in the capacitance of a capacitor-start motor, results in reduced (A) Noise. (B) Speed. (C) Starting torque. (D) Armature reaction.

Description : Reduction in the capacitance of a capacitor-start motor, results in reduced (A) Noise. (B) Speed. (C) Starting torque. (D) Armature reaction.

Last Answer : Ans: C Reduction in the capacitance reduces starting voltage, which results in reduced starting torque.

Explain the requirements of elevator motor. State with reason best suitable motor for elevator.

Description : Explain the requirements of elevator motor. State with reason best suitable motor for elevator.

Last Answer : Ideal requirements of elevator motor: 1. High starting torque along with high rate of acceleration and retardation. 2. Motors are compact in size especially smaller in diameter. 3. Speed of motor should not exceed 900 ... 4. Permanent magnet AC Motor. 5. Split Phase AC I.M. 6. Capacitor Start I.M.

Explain the suitability of 3-phase induction motor for traction service.

Description : Explain the suitability of 3-phase induction motor for traction service. 

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 { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }

Explain regenerative braking for D.C. series motor.

Description : Explain regenerative braking for D.C. series motor.

Last Answer : Schematic diagram of regenerative braking of D.C. series :-  Explanation of regenerative braking: During normal running, motors are connected in parallel with field winding in series ... For final stop mechanical braking is applied. External Resistances are connected to limit the current.

State any four desirable characteristics of ideal traction motor. State the names of different traction motor used.

Description : State any four desirable characteristics of ideal traction motor. State the names of different traction motor used.

Last Answer : Desirable characteristics of ideal traction motors:-  A) Mechanical Properties or characteristics: 1) It should be robust in construction to withstand against continuous vibrations. 2) Weight of motor per HP ... AC series motor 3. 3-Ph, Slip-ring induction motor 4. Linear induction motor (LIM)

Write eight desirable characteristics of traction motor.

Description : Write eight desirable characteristics of traction motor.

Last Answer : Desirable characteristics of ideal traction motors:- 1) It should be robust in construction to withstand against continuous vibrations. 2) Weight of motor per HP should be minimum in order to increase pay ... maintenance cost. 17) It should have high efficiency. 18) It should have long life.

"DC series motor is used for traction purpose." Justify your answer with any six characteristics.

Description : "DC series motor is used for traction purpose." Justify your answer with any six characteristics.

Last Answer : Due To Following Reasons DC Series Motor Is Used For Traction Purpose:- 1. DC Series motor robust in construction and capable to withstand against continuous vibration. 2. DC series motor weight is 1. ... . 12. Torque obtained by DC series motor is smooth and uniform, so it improves riding quality

How can noise be reduced?

Description : How can noise be reduced?

Last Answer : In order to be able to reduce disturbing noise levels, it is very important to identify two key elements. The first element is the source of the noise. The second is the frequency of the noise. Typically a vibration mount designed in accordance with vibration.

Noise can be reduced by A. widening the bandwidth B. narrowing the bandwidth C. increasing temperature D. increasing transistor current levels

Description : Noise can be reduced by A. widening the bandwidth B. narrowing the bandwidth C. increasing temperature D. increasing transistor current levels

Last Answer : B. narrowing the bandwidth

The noise output of a resistor is amplified by a noiseless amplifier having a gain of 60 and a bandwidth of 20 kHz. A meter connected at the output of the amplifier reads 1mV RMS. If the bandwidth of the amplifier is reduced to 5kHz, its gain remaining constant, what does the meter read now? A. 0.5 mV B. 0.5 µV C. 5.0 mV D. 5.0 µV

Description : The noise output of a resistor is amplified by a noiseless amplifier having a gain of 60 and a bandwidth of 20 kHz. A meter connected at the output of the amplifier reads 1mV RMS. If the bandwidth of the amplifier is reduced to ... does the meter read now? A. 0.5 mV B. 0.5 µV C. 5.0 mV D. 5.0 µV

Last Answer : A. 0.5 mV

Ambient noise level can be reduced by __________ decibels by planting trees (like coconut, neem etc.) near public utility buildings (like hospitals & schools). (A) 1-2 (B) 5-10 (C) 15-20 (D) 25-30

Description : Ambient noise level can be reduced by __________ decibels by planting trees (like coconut, neem etc.) near public utility buildings (like hospitals & schools). (A) 1-2 (B) 5-10 (C) 15-20 (D) 25-30

Last Answer : (B) 5-10

Pick out the correct statement. (A) Noise from ball mills can be dealt with by fibre glass lined enclosures (B) Noise from vibrating chutes can be reduced by lining the metallic chute with rubber (C) Noise of conveyor belt system is reduced by using urethane coated cloth conveyor belts and rubber/plastic covered metallic rollers (D) All (A), (B) & (C)

Description : Pick out the correct statement. (A) Noise from ball mills can be dealt with by fibre glass lined enclosures (B) Noise from vibrating chutes can be reduced by lining the metallic chute with rubber (C) Noise ... cloth conveyor belts and rubber/plastic covered metallic rollers (D) All (A), (B) & (C)

Last Answer : (D) All (A), (B) & (C)

Quantization noise can be reduced by ________ the number of levels. a) Decreasing b) Increasing c) Doubling d) Squaring

Description : Quantization noise can be reduced by ________ the number of levels. a) Decreasing b) Increasing c) Doubling d) Squaring

Last Answer : b) Increasing

Quantising noise can be reduced by increasing

Last Answer : Quantising noise can be reduced by increasing Number of standard quantum levels.

Applications of Dielectric Heating

Description : Applications of Dielectric Heating

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 { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }

Differentiate between core type and core less induction furnace.

Description : Differentiate between core type and core less induction furnace.

Last Answer : Sr.No. Core type induction furnace. Core less induction furnace. 1 Less leakage flux  More leakage flux 2 Power factor is good Power factor is poor 3 ... normal frequency is used. Due to high frequency, high voltage supply, time required for heating is less.

Justify the use of saturable reactor to control the magnitude of welding current.

Description :  Justify the use of saturable reactor to control the magnitude of welding current.

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 { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }

Explain the factors affecting framing of tariffs.

Description : Explain the factors affecting framing of tariffs.

Last Answer : Factors affecting framing of tariffs:- 1. Total recovery of all taxes , duties and other charges 2. Expenses on premium (installment) paid to insurance company. 3. T&D losses. 4. Electricity cannot ... L.F. 12. The tariff should be simple cheap and capable of easy explanation to consumers. 

State four advantages of seam welding over spot welding.

Description : State four advantages of seam welding over spot welding.

Last Answer : Advantages of seam welding over spot welding:- 1. Due to seam welding we get continuous weld which is air-tight 2. Gas tight as well as liquid tight joints can be made. 3. The Overlap is ... . The production of single seam weld and parallel seams can be got simultaneously. 5. Efficient energy use.

Explain with neat diagram construction and working of Ajax Wyatt vertical core induction furnace.

Description : Explain with neat diagram construction and working of Ajax Wyatt vertical core induction furnace.

Last Answer : Neat sketch of Ajax Wyatt' vertical core furnace: Construction of Ajax Wyatt' vertical core furnace: Vertical core type induction heating furnace is nothing but transformer. It consists of ... is utilized to melt the charge. Where, R = Resistance of charge & I secondary current.

State desirable properties of heating elements used in indirect resistance heating.

Description : State desirable properties of heating elements used in indirect resistance heating. 

Last Answer : Following properties of good heating material in indirect resistance heating:- 1. High resistivity: It should have high resistivity. So that it becomes compact in size and produces more heat with small ... , it should have low temperature co-efficient of resistance. 10.It should not be brittle.

Explain with the diagram butt welding. State its applications.

Description : Explain with the diagram butt welding. State its applications. 

Last Answer : Diagram butt welding:-  Explanation: Transformer used for welding is designed for low voltage and high current secondary. Transformer is oil cooled The job is clamped as shown in fig. two parts which ... : 1) For welding rod, wire, pipe etc 2) For joining thick metal plates or bars at end

State its types electrical braking.

Description : State its types electrical braking.

Last Answer : Types of Electrical Braking: Electrical braking system: 1. Plugging 2. Rheostatic (Dynamic) Braking 3. Regenerative Braking 4. Electromagnetic Braking 5. Eddy current braking

Explain the factors to be considered while designing a lighting scheme.

Description : Explain the factors to be considered while designing a lighting scheme.

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 { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }

State any factors to be considered while selecting electrical welding system.

Description : State any factors to be considered while selecting electrical welding system.

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 { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }

State two advantages of P.F. tariff and TOD tariff for the power system concern

Description : State two advantages of P.F. tariff and TOD tariff for the power system concern

Last Answer : time of day tariff:_ In time of day tariff structure incentives for power draw during peak off hours & extra charges for power draw during peak hours are built in. advantages:- 1. TOD tariff encourage ... advantages:-  1. kva rating of equipment reduces 2.due to high p.f less electricity bill.

State the four requirements of Tariff.

Description : State the four requirements of Tariff. 

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 { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }

State disadvantages of low power factor.

Description : State disadvantages of low power factor.

Last Answer : Due to low power factor The load draws high current. High cu losses. Efficiency decreases. Voltage regulation increases Temperature increases May break down  the insulation.

Give classification of electrical welding.

Description : Give classification of electrical welding.

Last Answer : i) Resistance Welding:- 1) Spot welding 2) Seam welding 3) Projection Welding 4) Butt Welding- i) Simple butt welding ii) Flash butt welding  ii) Arc welding:- 1) Carbon Arc Welding: a) shielded welding b) unshielded welding 2) Metal Arc Welding: a) shielded welding b) unshielded welding

Compare individual and group drive on any four points.

Description : Compare individual and group drive on any four points.  

Last Answer : S.No. Point Individual Drive Group Drive 1 Definition In this type of drive each machine has its own separate electric drive (motor). It may be directly coupled ... Lathe Machine (Similar application will be consider) Textile Industry (Similar application will be consider)

State eight requirements of an ideal traction system.

Description : State eight requirements of an ideal traction system.

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 { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }

Compare between Resistance welding and Arc welding on any six points.

Description : Compare between Resistance welding and Arc welding on any six points.

Last Answer : Sr.No Parameters Resistance Welding Arc Welding 1 Type of welding Plastic/Pressure/Non-fusion welding Fusion/Non pressure welding 2 Principle of heat developed Heat ... It is suitable for mass production It is suitable for heavy job, maintenance and repair work

State the four causes of low (poor) power factor.

Description : State the four causes of low (poor) power factor.

Last Answer : Following are the Causes of low power factor: - 1. Magnitude of Magnetizing Current :- As magnetizing current increases, power factor reduces. 2. Due to use of Induction Motor:- Most of industrial ... and maintenance:- P.f. falls if proper maintenance or repairs of equipments are not done. 

State any two applications of each for the following types of electrical heating : (i) Direct resistance heating(ii) Indirect induction heating (iii) Direct.arc heating (iv) Dielectric heating

Description : State any two applications of each for the following types of electrical heating : (i) Direct resistance heating(ii) Indirect induction heating (iii) Direct.arc heating (iv) Dielectric heating

Last Answer : (i) Direct resistance heating:- 1. This type of heating used for industrial purpose 2. Salt bath heating: This utilized for the purpose of carbonizing, tempering, quenching and hardening of steel tools 3. ... purpose. 14)In foundry for heating of sand, core, which are used in molding processes.

Describe with neat sketch operation of seam type resistance welding.

Description : Describe with neat sketch operation of seam type resistance welding.

Last Answer : 1) Seam Welding its neat labelled sketch:  Explanation: Seam welding is nothing but series of continuous spot welding Working: Job is kept in between two electrodes under ... reached supply is cut down and external pressure is applied simultaneously across the job to complete weld.  

Describe the construction of high pressure mercury vapour lamp with neat sketch

Description :  Describe the construction of high pressure mercury vapour lamp with neat sketch

Last Answer : Construction:-  It consists of an inner bulb generally of silicon, to withstand high temperatures. The bulb contains a small quantity of mercury and argon. It is protected by outer glass, this ... : The function of power factor improvement capacitor is to improve the power factor 0.5 to 0.95

Draw a neat labelled block diagram of AC electric locomotive. State the function of each part.

Description : Draw a neat labelled block diagram of AC electric locomotive. State the function of each part.

Last Answer : labelled diagram ofAC electric locomotive:  Function of AC electric locomotive Parts: 1) Overhead contact wire: Supply of 1-ph, 25KV, 50Hz, AC is given to overhead conductor. 2) Current collecting ... mechanical power to run the train i.e. DC series motor which is used as traction motor.

Compare DC and AC welding on any four points.

Description : Compare DC and AC welding on any four points.

Last Answer : Points DC Welding AC Welding Supply equipment used  DC differential Compound Generator, or Rectifier Welding Transformer Heating Effect Uniform Not Uniform Temperature Obtain ... High, 85% Application Carbon Arc Welding Resistance Welding , Metal Arc Welding

Compare Single phase 25 kV AC and 1500 V DC track electrification.

Description : Compare Single phase 25 kV AC and 1500 V DC track electrification.

Last Answer : Points Single phase 25 kV AC track Electrification 1500 V DC track electrification Supply given to O/H condition 1-ph, 25KV, AC 50 Hz  600/750V-Tromways 1500/3000V urban/suburban ... track distance Less More Applications Main line services Urban and suburban area

Advantages eddy current heating

Description : Advantages eddy current heating

Last Answer : 1) No heat transfer loss as heat is produced in job itself. So it has high efficiency. 2) As heat is produced in job itself so time required for heating is less. For e.g. in some ... or other special atmospheric condition where other methods are not possible. 9) It is clean and convenient method.

State any eight advantages of electric heating.

Description :  State any eight advantages of electric heating.

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 { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }

State advantages and disadvantages of electric braking over mechanical braking.

Description : State advantages and disadvantages of electric braking over mechanical braking.

Last Answer : Advantages: 1. It is most reliable braking system. 2. Breaking actuation time is small as higher value of braking retardation is obtained. 3. Electrical braking is smooth & gradual. 4. Life of ... energy is surplus. 4. Initial cost is more due to other control equipments & circuitry. 

State the various types of welding.

Description : State the various types of welding.

Last Answer : i) Resistance Welding:- 1) Spot welding 2) Seam welding 3) Projection Welding 4) Butt Welding- i) Simple butt welding ii) Flash butt welding   ii) Arc welding:- 1) Carbon Arc Welding: a) shielded welding b) unshielded welding 2) Metal Arc Welding: a) shielded welding b) unshielded welding

State the principle of induction heating. Write four applications of induction heating.

Description : State the principle of induction heating. Write four applications of induction heating.

Last Answer : Principle of Induction heating: The basic principle of induction heating is that, supply is given to primary winding of furnace transformer & heat is produced in the secondary (charge) due to ... utilized to melt the charge. Where, R = Resistance of charge & I secondary current

Define load equalisation for electric motors. Explain how it is obtained for electric motors.

Description : Define load equalisation for electric motors. Explain how it is obtained for electric motors.

Last Answer : Define load equalization for electric Motor: There are many types of load which are fluctuating in nature e.g. wood cutting m/c, Rolling mill. Etc. For such type of loads, load equalization is ... increases so cost of cable increases, Hence it is necessary to smooth out load fluctuations on motor.

State the factors to be considered for selection of shape and size of the car of elevator.

Description : State the factors to be considered for selection of shape and size of the car of elevator.

Last Answer : The size and shape of elevator car depends on following factors:  i) No. of passenger to be carried: While selecting the size of car it is a usual practice to allow. A Space of 2 Sq. ... of elevator depends on space available in building.  iii) Type of building  iv) Application of elevator

State the causes of failure of heating element.

Description : State the causes of failure of heating element.

Last Answer : Following of the different causes of failure of heating element:  i) Formation of hot spot: Hot spot on heating element is the point which is at higher temperature than remaining heating element ... & cooling of heating element, it may break (fail) due to small mechanical injury also.

Define electric drive. List at least four advantages of electric drive.

Description : Define electric drive. List at least four advantages of electric drive.

Last Answer : Electric Drive: It is a machine which gives mechanical power. e.g. drives employing electric motors are known as electric drives. Following advantages of electric drive: 1. It is more economical. 2. It ... . 13. Less maintenance cost. 14. It has long life. 15. It is reliable source of drive.