800+ TOP Mechanical Engineering LAB VIVA Questions and Answers

Below are the list of all Mechanical ENGINEERING Lab Viva Questions and Answers for Mechanical students.also we can provide 2mark important objective type books & Interview questions

Mechanical Engineering VIVA Questions with Answers pdf:-

1.Fluid Mechanics

2.Thermal engineering

3.Thermodynamics

4.I.C Engines

5.Nuclear Power Plants

6.Steam Boilers, Engines, Nozzles and Turbines

7.Compressors,Gas Turbines & Jet Engines 

8.Heat Transfer

9.Refrigeration and Air Conditioning

10.Measurements and Instrumentations

11.Machine Design

12.Theory of Machines

13.Hydraulic Mechanics

14.Workshop Technology 

15.PLC 

16. MMM

17. MMT

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MECHANICAL Engineering LAB VIVA Questions and Answers
MECHANICAL Engineering LAB VIVA Questions

Especially we are prepare for the Mechanical freshers and Experienced Candidates, these model questions are asked in the online technical test, Quiz and interview of many companies.

These are also very important in your university exams like JNTU, Andhra,OU,Anna university,Pune,VTU,UPTU,CUSAT etc.

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100+ TOP THERMAL Engineering VIVA Questions and Answers

THERMAL Engineering VIVA Questions :-

1. Define heat transfer?
Heat transfer can be defined as the transmission of energy from one region to another due to temperature difference.

2. What are the modes of heat transfer?

  • Conduction
  • Convection
  • Radiation.

3. What is conduction?
Heat conduction is a mechanism of heat transfer from a region of high temperature to a region of low temperature within a medium [solid, liquid or gases] or different medium in direct physical contact.

4. State Fourier’s law of conduction.
The rate of heat conduction is proportional to the area measured normal to the direction of heat flow and to the temperature gradient in that direction.
Q α – A dT / dx
Q = -kA dT /dx
Where, A – Area in m2
.
dT / dx – Temperature gradient, K/m
k – Thermal conductivity, W/mK.

5. Define Thermal conductivity.
Thermal conductivity is defined as the ability of a substance to conduct heat.

6. Write down the equation for conduction of heat through a slab or plane wall.
Heat transfer, Q = ∆ Toverall / R
Where, ∆ T = T1 – T2
R = L / kA – Thermal resistance of slab
L – Thickness of slab
K – Thermal conductivity of slab
A – Area

7. What are the factors affecting the thermal conductivity?

  1. Moisture b. Density of material c. Pressure
  2. Temperature e. Structure of material.

8. What is meant by free or natural convection?
It is fluid motion is produced due to change in density resulting from temperature gradients, the mode of heat transfer is said to be free or natural convection.

9. Define Grashof number [Gr].
It is defined as the ratio of product of inertia force and buoyancy force to the
square of viscous force. Gr = Inertia force x Buoyancy force / [Viscous force]2

10. Define Stanton number [St].
It is the ratio of Nusselt number to the product of Reynolds number and
Prandtl number. St = Nu / Re x Pr.

11. What is meant by Newtonion and non-newtonion fluids?
The fluids which obey the Newton’s law of viscosity are called Newtonion fluids and those which do not obey are called no-newtonion fluids.

12. What is meant by laminar flow ?
Laminar flow: Laminar flow is sometimes called stream line flow. In this type of flow, the fluid moves in layers and each fluid particle follows a smooth continuous path. The fluid particles in each layer remain in an orderly sequence without mixing with each other.

13. Define Convection.
Convection is a process of heat transfer that will occur between a solid surface and a fluid medium when they are at different temperatures.

14. Define Reynolds number [Re].
It is defined as the ratio of inertia force to viscous force.
Re = Inertia force / Viscous force

15. Define Prandtl number [Pr].
It is the ratio of the momentum diffusivity to the thermal diffusivity.
Pr = Momentum diffusivity / Thermal diffusivity

16. Define Nusselt Number [Nu].
It is defined as the ratio of the heat flow by convection process under an unit temperature gradient to the heat flow rate by conduction under an unit temperature gradient through a stationary thickness [L] of metre.

Nusselt Number [Nu] = qconv /qcond

17. State Newton’s law of convection.
Heat transfer from the moving fluid to solid surface is given by the equation.
Q = h A = [Tw – T∞]
This equation is referred to as Newton’s law of cooling.
Where h = Local heat transfer coefficient in W/m2K.
A = Surface area in m2
.
Tw = Surface [or] Wall temperature in K.
T∞ = Temperature of fluid in K.

18. What is forced convection?
If the fluid motion is artificially created by means of an external force like a blower or fan, that type of heat transfer is known as forced convection.

19. What are the dimensionless parameters used in forced convection?

  1. Reynolds number [Re].
  2. Nusselt number [Nu].
  3. Prandtl number [Pr].

20. Mention Stefan boltzman contant.
σ = Stefan Boltzman constant = 5.6697 x 10-8 W/ (m² K4)

21. Define Stefan boltzman contant.
Stefan Boltzman law states that the total emissive power of a perfect black body is proportional to
fourth power of the absolute temperature of black body surface
Eb = σT
4
σ = Stefan Boltzman constant = 5.6697 x 10-8 W/ (m² K4)

22. Define Emissive power [Eb].
The emissive power is defined as the total amount of radiation emitted by a body per unit time and unit area. It is expressed in W/m2

23. Define monochromatic emissive power. [Ebλ]
The energy emitted by the surface at a given length per unit time per unit area in all directions is known as monochromatic emissive power.

24. What is meant by absorptivity?
Absorptivity is defined as the ratio between radiation absorbed and incident radiation. Absorptivity, α = Radiation absorbed / Incident radiation.

25. Define Radiation.
The heat transfer from one body to another without any transmitting medium is known as radiation. It is an electromagnetic wave phenomenon.

26. Define Emissivity.
It is defined as the ability of the surface of a body to radiate heat. It is also defined as the ratio of emissive power of any body to the emissive power of a black body of equal temperature.

Emissivity, ε = E / Eb.

27. Define Emissive power [Eb].
The emissive power is defined as the total amount of radiation emitted by a body per unit time and unit area. It is expressed in W/m2.

28. Define monochromatic emissive power. [Ebλ]
The energy emitted by the surface at a given length per unit time per unit area in all directions is known as monochromatic emissive power.

29. What is meant by absorptivity?
Absorptivity is defined as the ratio between radiation absorbed and incident radiation.
Absorptivity, α = Radiation absorbed / Incident radiation.

30. What is meant by reflectivity?
Reflectivity is defined as the ratio of radiation reflected to the incident radiation.
Reflectivity, ρ = Radiation reflected / Incident radiation.

31. What is meant by transmissivity?
Transmissivity is defined as the ratio of radiation transmitted to the incident radiation.
Transmissivity, τ = Radiation transmitted / Incident radiation.

32. What is black body?
Black body is an ideal surface having the following properties.

  • A black body absorbs all incident radiation, regardless of wav e length and direction.
  • For a prescribed temperature and wave length, no surface can emit more energy than black body.

33. What is meant by gray body?
If a body absorbs a definite percentage of incident radiation irrespective of their wave length, the body is known as gray body. The emissive power of a gray body is always less than that of the black body.

34. What is heat exchanger?
A heat exchanger is defined as an equipment which transfers the heat from a hot fluid to a cold fluid.

35. What is meant by Direct heat exchanger [or] open heat exchanger?
In direct contact heat exchanger, the heat exchange takes place by direct mixing of hot and cold fluids.

36. What is meant by Indirect contact heat exchanger?
In this type of heat exchangers, the transfer of heat between two fluids could be carried out by transmission through a wall which separates the two fluids.

37. What is meant by parallel flow heat exchanger?
In this type of heat exchanger, hot and cold fluids move in the same direction.

38. What is meant by counter flow heat exchanger?
In this type of heat exchanger, hot and cold fluids move in parallel but opposite directions.

39. What is meant by cross flow heat exchanger?
In this type of heat exchanger, hot and cold fluids move at right angles to each other.

40. What is meant by Shell and tube heat exchanger?
In this type of heat exchanger, one of the fluids moves through a bundle of tubes enclosed by a shell. The other fluid is forced through the shell and it movesover the outside surface of the tubes.

41. What is meant by LMTD?
We know that the temperature difference between the hot and cold fluids in the heat exchanger varies from point to point. In addition various modes of heat transfer are involved. Therefore based on concept of appropriate mean temperature difference, also called logarithmic mean temperature difference, the total heat transfer rate in the heat exchanger is expressed as

Q = U A [∆T]m Where, U=Overall heat transfer co-efficient [W/m2K], A=Area, m2
[∆T]m = Logarithmic mean temperature difference.

42. What is meant by Effectiveness?
The heat exchanger effectiveness is defined as the ratio of actual heat transferto the maximum possible heat transfer.
Effectiveness ε = Actual heat transfer / Maximum possible heat transfer = Q / Qmax

43. Power requirement of a refrigerator is___________.
Inversely proportional to COP.

44. In SI units, one ton of refrigeration is equal to _________.
210 kJ/min.

45. Define tons of refrigeration and COP.
A tonne of refrigeration is defined as the quantity of heat required to beremoved from one tonne of water [1000 kg] at 00C to convert that into ice at 00C in24 hours. In actual practice,1 tonne of refrigeration = 210kJ/min = 3.5kW.

46. The capacity of a domestic refrigerator is in the range of ___________.
1 to 3 tonne.

47. Name four important properties of a good refrigerant.

  • Low boiling point.
  • High critical temperature & pressure.
  • Low specific heat of liquid.

48. What is the difference between air conditioning and refrigeration?
Refrigeration is the process of providing and maintaining the temperature in space below atmospheric temperature. Air conditioning is the process of supplying sufficient volume of clean aircontaining a specific amount of water vapour and maintaining the predeterminedatmospheric condition with in a selected enclosure.

49. Name any four commonly used refrigerants.
1. Ammonia [NH3].
2. Carbon dioxide [CO2].
3. Sulphur di oxide [SO2].
4. Freon – 12. Dr. N.N.C.E MECH/ VI Sem TE LAB II – LM52

50. What are the advantages and disadvantages of air refrigeration system?
Advantages:
1. The refrigerant used namely air is cheap and easily available.
2. There is no danger of fire or toxic effects due to leakages.
3. The weight to tonne of refrigeration ratio is less as compared to other systems.
Disadvantages:
1. The quantity of refrigerant used per tonne of refrigeration is high as compared to other system.
2. The COP of the system is very low. Therefore running cost is high.
3. The danger of frosting at the expander valves is more as the air contains moisture content.

51. What is net refrigerating effect of the refrigerant?
Refrigerating effect is the total heat removed from the refrigerant in the evaporator.
COP = Refrigeration effect / Work done.
Refrigeration effect = COP x Work done.

52. Define refrigerant.
Any substance capable of absorbing heat from another required substance canbe used as refrigerant.

300+ TOP Fluid Mechanics LAB VIVA Questions and Answers

Fluid Mechanics LAB VIVA Questions :-

1. Why the Centrifugal Pump is called High Discharge pump?
Centrifugal pump is a kinetic device. The centrifugal pump uses the centrifugal force to push out the fluid. So the liquid entering the pump receives kinetic energy from the rotating impeller. The centrifugal action of the impeller accelerates the liquid to a high velocity, transferring mechanical (rotational) energy to the liquid. So it discharges the liquid in high rate. It is given in the following formula:
Centrifugal force F= (M*V2)/R.
Where,

  • M-Mass
  • V-Velocity
  • R-Radius

2. How Cavitation can be eliminated by Pump?
Cavitation means bubbles are forming in the liquid.

  1. To avoid Cavitation, we have to increase the Pump size to One or Two Inch;
  2. To increase the pressure of the Suction Head, or
  3. Decrease the Pump Speed.

3. Why Cavitation will occur in Centrifugal Pump and not in Displacement Pump?
The formation of cavities (or bubbles) is induced by flow separation, or non-uniform flow velocities, inside a pump casing. In centrifugal pumps the eye of the pump impeller is smaller than the flow area of pipe. This decrease in flow area of pump results in increase in flow rate. So pressure drop happened between pump suction and the vanes of the impeller. Here air bubbles or cavities are formed because of liquid vapour due to increase in temperature in impeller. This air bubbles are transmitted to pump which forms cavitation.

4. Which Pump is more Efficient Centrifugal Pump or Reciprocating Pump?
Centrifugal pump. Because flow rate is higher compared to reciprocating pump. Flow is smooth and it requires less space to install. Lower initial cost and lower maintenance cost.

5. Why Centrifugal Pump is not called as a Positive Displacement Type of Pump?
The centrifugal has varying flow depending on pressure or head, whereas the Positive Displacement pump has more or less constant flow regardless of pressure.
Likewise viscosity is constant for positive displacement pump where centrifugal pump have up and down value because the higher viscosity liquids fill the clearances of the pump causing a higher volumetric efficiency. When there is a viscosity change in supply there is also greater loss in the system. This means change in pump flow affected by the pressure change.
One more example is, positive displacement pump has more or less constant efficiency, where centrifugal pump has varying efficiency rate.

6. How Cavitation can be eliminated in a Pump?
Cavitation means bubbles are forming in the liquid.

  • To avoid Cavitation, we have to increase the Pump size to One or Two Inch;
  • To increase the pressure of the Suction Head, or
  • Decrease the Pump Speed.

7. Which pump is more efficient Centrifugal pump or Reciprocating pump?
Centrifugal pump.
Because flow rate is higher compared to reciprocating pump. Flow is smooth and it requires less space to install. Lower initial cost and lower maintenance cost.

8. Why Centrifugal Pump is not called as a Positive Displacement Type of Pump?

  • The centrifugal has varying flow depending on pressure or head, whereas the Positive Displacement pump has more or less constant flow regardless of pressure.
  • Likewise viscosity is constant for positive displacement pump where centrifugal pump have up and down value because the higher viscosity liquids fill the clearances of the pump causing a higher volumetric efficiency. When there is a viscosity change in supply there is also greater loss in the system. This means change in pump flow affected by the pressure change.
  • One more example is, positive displacement pump has more or less constant efficiency, where centrifugal pump has varying efficiency rate.

9. What is a radial-flow turbine?
In a radial-flow turbine, steam flows outward from the shaft to the casing. The unit is usually a reaction unit, having both fixed and moving blades.

10. What are four types of turbine seals?

  • Carbon rings fitted in segments around the shaft and held together by garter or retainer springs.
    Labyrinth mated with shaft serration’s or shaft seal strips.
  • Water seals where a shaft runner acts as a pump to create a ring of water around the shaft. Use only treated water to avoid shaft pitting.
  • Stuffing box using woven or soft packing rings that are compressed with a gland to prevent leakage along the shaft.

11. What are two types of clearance in a turbine?

  1. Radial – clearance at the tips of the rotor and casing.
  2. Axial – the fore-and-aft clearance, at the sides of the rotor and the casing.

12. What is the function of a thrust bearing?
Thrust bearings keep the rotor in its correct axial position.

13. What is a stage in a steam turbine?
In an impulse turbine, the stage is a set of moving blades behind the nozzle. In a reaction turbine, each row of blades is called a “stage.” A single Curtis stage may consist of two or more rows of moving blades.

14. What is a diaphragm?
Partitions between pressure stages in a turbine’s casing are called diaphragms. They hold the vane-shaped nozzles and seals between the stages. Usually labyrinth-type seals are used. One-half of the diaphragm is fitted into the top of the casing, the other half into the bottom.

15. What are the two basic types of steam turbines?

  • Impulse type.
  • Reaction type.

16. What are topping and superposed turbines?
Topping and superposed turbines arc high-pressure, non-condensing units that can be added to an older, moderate-pressure plant. Topping turbines receive high-pressure steam from new high-pressure boilers. The exhaust steam of the new turbine has the same pressure as the old boilers and is used to supply the old turbines.

17. What is a combination thrust and radial bearing?
This unit has the ends of the Babbitt bearing extended radically over the end of the shell. Collars on the rotor face these thrust pads, and the journal is supported in the bearing between the thrust collars.

18. How Cavitation can be eliminated in a Pump?

  1. Increase the Pump size to One or Two Inch,
  2. Increase the pressure of the Suction Head,
  3. Decrease the Pump Speed.

19. One litre = ________cm3 .
1000 cm3 .

20. Which Pump is more Efficient Centrifugal Pump or Reciprocating Pump?
Centrifugal pump. Because flow rate is higher compared to reciprocating pump. Flow is smooth and it requires less space to install. Lower initial cost and lower maintenance cost.

21. Differentiate between the Uniform Flow and Non-Uniform Flow?
Uniform Flow: The flow is defined as uniform flow when in the flow field the velocity and other hydrodynamic parameters do not change from point to point at any instant of time.
Non-Uniform Flow: When the velocity and other hydrodynamic parameters changes from one point to another the flow is defined as non-uniform flow.

22. What is Coefficient of contraction?
Coefficient of contraction is the ratio of area of jet at vena contracta to the area of orifice.
The typical value may be taken as 0.64 for a sharp orifice (concentric with the flow channel). The smaller the value, the more effect the vena contracta has.

[PDF Notes] Classification of overheads is the process of grouping of the overheads according to their common characteristics

Classification of overheads is the process of grouping of the overheads according to their common characteristics. Overheads are classified on the basis of (i) Elements (ii) Functions and (iii) Behavior.

Overheads can be classified on the basis of elements in three groups as stated below: (i) Indirect material, (ii) Indirect labour and (iii) Indirect Expenses

(i) Indirect Materials: All those materials which do not form a part of the finished product or cannot be identified in the product conveniently are known indirect materials.

The examples are consumable stores, loose tools, wastrel cotton, lubricating oil, fuel, stationery, postages, etc. There are some materials which, even though, form a part of the finished product are treated as indirect I materials because they contribute a very small part of the total expenses. The examples are nuts, bolts, screws, threads, nails, etc.

(ii) Indirect labour: There are several labour costs which are not directly engaged I for production of goods and services. These labour costs come under indirect of labour. Some of the examples are salary of supervisor, works manager; wages to I coolie, watchman, electrician, storekeeper, timekeeper; director’s fees, overtime payments, cost of idle time, etc.

(iii) Indirect expenses: Indirect expenses are those costs other than indirect materials and indirect labour which cannot be directly identified with a job or product.

The examples of indirect expenses are canteen expenses, repairs, depreciation, insurance, rent, rates, taxes, factory telephone, telegram and postage expenses, lighting, heating, advertisement, first aid and hospital expenses.

The above are broadly divided into cash expenses and non-cash expenses. Depreciation on plant, machinery, factory building, notional rent and interest outstanding expenses are the examples of non-cash expenses, whereas amount paid in cash are cash expenses.

Classification by Function

i) Factory or manufacturing overheads

(ii) Administrative or office overheads

(iii) Selling overheads

(iv) Distribution overheads

Overheads can be classified on the basis of the major functions of a business concern as shown below:

(i) Factory or Manufacturing Overheads: This is also known as production overheads or works overheads. Factory overheads represent all the indirect costs, i.e. indirect materials, indirect labour and indirect expenses incurred in connection with production of product or services. Following are the examples:

Indirect Materials: Consumable stores, grease, lubricating oil, cotton waste, loose tools, postages and stationeries used in the production departments, etc.

Indirect labour: Salary of factory supervisor, works manager, store keeper, foreman, etc.

Indirect expenses: Factory rent, factory lighting, factory repairs and maintenance, depreciation of factory building and machines, etc.

(ii) Administrative or Office Overheads: It is the indirect expenditures incurred in formulating poli y, directing the organisation, controlling and managing the operations of an undertaking other than production, selling, distribution, research and development activities.

This represents indirect materials, indirect labour and indirect expenses incurred by the administrative department in the office. Following are the examples of administrative overheads:

Indirect Materials: Cost of printing and stationary used in the office, cleaning materials, water containers, etc.

Indirect labour: Salary of Managing Director, Directors, General Managers, Accountants, Managers, Secretary, other staff of the office, clerks, Legal advisors, etc.

Indirect Expenses: Office rent, lighting, rates and taxes, Repairs, Insurance and depreciation of office building, furniture or equipment’s, telephone expenses, legal charges, bank charges, etc.

(iii) Selling Overheads: Selling overheads represent those costs which are incurred for promoting sales, stimulating demands and facilitating selling of an organisation. In other words, this includes the indirect costs which are associated with marketing and selling and advertising activities. Following are the examples of overheads of sales department and sale management:

Indirect Materials: Printing and stationary used in sales department, catalogue free gifts, etc.

Indirect labour: Salary of sales manager, sales officers, other staff of sales department, commission to agents, etc.

Indirect expenses: Rent, rates and taxes of sales showroom, repair, maintenance, depreciation of sales office building, equipment and furniture, sales office telephone expenses lighting, heating of sales office, advertisement, bad debt, travelling expenses of salesman, etc.

(iv) Distribution Overheads: Distribution overheads represent those costs which are incurred from the time the product is completed in the factory until it reaches ultimate consumers.

It includes packing expenses, storage expenses and transportation expenses. In other words all indirect materials, indirect labour and indirect expenses incurred by distribution departments are known as distribution overheads. Following examples will make it clear.

Indirect material: Printing and stationary used in distribution office, secondary packing materials, etc.

Indirect labour: Salary to staff attached to distribution office, vehicle driver, coolie, etc.

Indirect expenses: Rent, rates, taxes in the ware house go down, repairs, maintenance, insurance, depreciation of warehouse go down, equipment, furniture, delivery van of distribution office, telephone expenses of distribution office, lighting, heating, cleaning of distribution office, etc.

Classification by Behavior / Variability

Overheads can be classified on the basis of their tendency to vary with the volume of production or sales or activity level. Behavior-wise, the overheads are grouped as under:

(i) Fixed overheads.

(ii) Variable overheads.

(iii) Semi-variable overheads.

(i) Fixed Overheads:

Fixed overheads are those indirect costs which do not change inspired of the change in levels of production up to a given range? In other words, if the level of output goes up or comes down these overheads remain constant.

For instance the salary of a manager or the rent of a building does not vary even if we increase or decrease the volume of production.

Fixed overheads are also known as period cost, policy cost; stand by cost or shutdown cost. The examples fixed overheads are rent of building, plant and machinery; depreciation of building, plant and machinery; salary of Directors, Managers, clerks, accountants, office expenses such as postages, printing, stationary, bank charges legal fees, etc.

It is very important to note that the fixed overheads although remain fixed for a particular level of output, they are not wholly fixed in nature. When a business firm increases its capacity, it has to arrange additional fixed costs such as building, plant, machinery, etc. and this will result in more fixed overheads.

The following graph shows the behavior of fixed overheads:

Total Fixed Overheads

Fixed Cot per unit

Units of Production

The specialty of fixed overhead cost is that the total fixed overheads remain same as all levels of output within a certain range. This line is parallel to the ‘X’ axis. But the fixed overhead per unit varies with the level of production. That means when production level increases the unit fixed overhead decreases and vice versa.

(ii) Variable overheads:

Variable overheads are those indirect costs which vary in direct proportion to the’ volume of output. In other words, when the output increases the total variable overheads increases proportionately and vice versa. But the variable overhead per unit remains fixed at different levels of activity.

The examples of variable overheads are fuel, power, maintenance, depreciation, lubricants, idle time cost, commission to sales man, spoilage, etc.

The following graph shows the behavior of the variable overheads:

Total variable overheads

Variable overhead per unit

Units of Production

(iii) Semi-Variable overheads:

Semi-variable overheads are those indirect costs which remain constant to a certain extent and proportionately vary thereafter.

These overheads are partly fixed and partly variable. For instance, telephone expenses include fixed charge plus variable charge according to the number of calls. Some, times the sales representatives are entitled to a fixed salary plus a commission beyond a certain level of sales. This is a semi-variable overhead. The examples of semi variable overheads are repairs, maintenance, depreciation of plant and machinery, telephone charges.

The graph of semi-variable overhead is shown below to indicate its behavior:

[PDF Notes] Here are your brief notes on Allocated and Apportionment of Overheads

After classification of overheads all the items of overheads are collected properly under suitable account heading. The next step is allocation and apportionment of overheads. This is also known as departmentalisation or primary distribution of overheads.

Before discussing allocation and apportionment or departmentalisation of overheads, it is essential to study the different types of departments or cost centers. In a manufacturing concern there can be broadly two categories of departments namely production departments and service departments.

Production Departments:

Production departments are those departments where actual process of manufacturing is carried on. For example in a cotton textile mill, spinning, weaving and finishing departments are production departments. In the production departments, with the help of manual and or machine operations the raw materials are converted to finished goods.

Example: In steel, rolling mill, hot mill, cold mill, polishing, grinding are the production departments.

Service Departments:

Service departments are auxiliary and are those departments which are not directly engaged in production. These departments are essential for smooth and efficient running of production departments. Such departments render services such as repairs, maintenance, electricity, etc. for the benefit of other departments.

Example: Stores, cost office, personnel dept. labour welfare dept., canteen, time keeping, repairs and maintenance, tool room, hospital etc.

A department may be either production department or service department depending upon the nature and function. But there are some service departments which occasionally engaged in production apart from rendering services.

These are called partly producing departments. For example, a carpentry unit which does repairs of furniture and fittings may be engaged to manufacture packing boxes. In such case it will be a partly producing department.

Allocation Of Overhead

Allocation of overheads is the process of charging whole amount of an individual item of cost directly to the cost center or department. An expense which is directly identifiable with a specific cost center is allocated to that cost center.

For example when separate electric meters are installed in different departments, the electricity charges basing on the electricity bills can be allocated to respective departments. Rent of canteen building is allocated to canteen. Similarly the indirect wages of different departments can be directly allocated to the respective departments.

Apportionment Of Overhead

Apportionment of overheads is the process of charging the proportion of common items of cost to different cost centers. When whole of one item of cost cannot be identified wholly with a particular cost center or department, such expense requires division or apportionment over two or more cost centers.

These overhead items are known as common costs or omnibus expenses. While dividing the common cost among two or more departments, a suitable or rational basis is considered. For example, the whole of factory rent needs to be apportioned among various departments on the basis of floor area occupied by respective departments.

Similarly when there is one electric meter in the factory, the common electricity charges should be apportioned to various departments on the basis of the light points or floor area.

Guidelines of Apportionment:

The guidelines or principles which facilitate in determining a suitable basis for apportionment of overheads are explained below:

1. Derived Benefit:

According to this principle, the apportionment of common item of overheads should be based on the actual benefit received by the respective cost centers. This method is applicable when the actual benefits are measurable. For example, rent can be apportioned on the basis of floor area occupied by each department.

2. Potential Benefit:

According to this principle, the apportionment of common item of overheads should be based on potential benefits (i.e. benefits likely to be received). When the measurement of actual benefit is difficult or impossible or uneconomical this method is adopted. For example, the cost of canteen can be apportioned as the basis of number of employees in each department which is a potential benefit.

3. Ability to pay:

According to this method, overheads should be apportioned on the basis of the sales ability or income generating ability of respective departments. In other words, the departments which contribute more towards profit should get a higher proportion of overheads.

4. Efficiency method:

According to this principle, the apportionment of overheads is made on the basis of the production targets. If the target is higher, the unit cost reduces indicating higher efficiency. If the target is not achieved the unit cost goes up indicating inefficiency of the department.

5. Specific criteria method:

According to this principle, apportionment of overheads is made on the basis of specific criteria determined in a survey.

Hence this method is also known as ‘Survey method’. When it is difficult to select a suitable basis in other methods, this method is adopted. For example, while apportioning salary of foreman, a careful survey is made to know how much time and attention is given by him to different departments. On the basis of the above survey the apportionment is made.

100+ TOP Electrical Engineering Seminar Topics

Electrical Engineering Seminar Topics :-

    1. Improved Reactive Power Capability of Grid Connected Doubly Fed Induction Generator
    2. Synchronization or Paralleling of Generators
    3. Analysis of Solar Thermal Power Generation
    4. Modern Speed Control Technologies of AC Motors
    5. Robotic Motors or Special Motors
    6. Transformers: Basics and Types
    7. Soft Starting of Motors with an Improved Power Factor
    8. Applications of Fuel Cells
    9. Energy Efficient Motors
    10. Improved Direct Torque Control of Induction Motor with Dither Injection
    11. Electrical AC and DC Drives
    12. Modern Trends in Machine Design Technology
    13. Variable Frequency Transformer Model Analysis by MATLAB
    14. Home Automation System
    15. SCADA and Power System Automation
    16. Fuzzy Logic Based Flow Control
    17. Distributed Control System for Industrial Automation
    18. Process Dynamics, Control and Automation using LABVIEW
    19. Irrigation Control System
    20. PID Controllers for Industrial Process Control
    21. Industrial Networking Using Various Field Buses
    22. Closed Loop Control of Converter Fed Motor
    23. Programmable Logic Controllers (PLC) vs. DCS
    24. Real-Time Simulation of Power System
    25. Wireless Power Transmission via Solar Power Satellite
    26. Substation Automation Communication Protocol
    27. Power Quality Issues with Grid Connected Wind Energy Systems
    28. Power Factor Improvement Methods
    29. Need for Reactive Power Compensation
    30. Automated Energy Meter Reading for Billing Purpose
    31. Voltage and Power Stability of HVDC Systems
    32. Power System Operation and Control
    33. Performance of 400KV Line Insulators Under Pollution
    34. LED Lighting for Energy Efficiency
    35. Wireless Power Transfer through Coils