Interview Questions and Answers – Mechanical Engineering Design, Safety and Maintenance

rp_01-job-interview-techniques-300x199.jpgMechanical Engineering Interview Questions and answers for freshers on design, safety and maintenance.


1) What is an accident ?

An accident is a unexpected and unforeseen event which may or may not injury to a person or a machine tool.


2) What are the standard sizes of drawing board as per Indian Standards?

As per Indian Standards :1250×900,900×650,650×500,500×350,350×250 sizes are available.


3) What are the functions of a scale ?

(a) To measure distance accurately.
(b) For making drawing to scale either in full size, reduced size or enlarged size.


4) What is a sketching ?

This is freehand expression of the graphic language.


5) What do you mean by First Aid ?

First Aid is immediate and temporary care given to a person who affected accidental injury or a sudden illness before the arrival of doctor.


6) What is a Drawing ?

It is a graphical representation of a real thing to define and specify the shape and size of a particular object by means of lines.


7) What is Engineering Drawing ?

A drawing which is worked out an engineer for the engineering purpose is known as Engineering Drawing.


8)  What are the methods of extinguishing fire ?

1) Starvation. Separating or removing the burning material from the neighbour hood of the fire.
2) Blanketing. Preventing the air flow to the fire.
3) Cooling. Lowering the heat created by burning materials.


9)  What are the precautions to be taken to avoid fire ?

1) The buckets along with sand should be placed inside the workshop.
2) Switches and other electrical parts must be made of fireproof material.
3) Carbon dioxide gas should be place at required points in special containers.
4) Fire extinguishers of suitable type should be placed at accessible places.


10) What safety precautions should be observed while working in the workshop ?

1) Keep shop floor clean, free from oil and other slippery materials.
2) Wear proper dress and avoid loose clothing and loose hair.
3) Wear shoes and avoid chapels.
4) Avoid playing, loose talk and funning inside the shop floor.
5) Keep good housekeeping and put all unnecessary items and rejected items in scrap box.
6) Learn everything about the machine before starting and clear all the doubts.
7) Keep a safe distance from rotating and sliding parts.
8) Never store inflammable materials inside or around the shop.
9) Never play with electricity, fire, parts with sharp edge etc.
10) Keep fire buckets and extinguishers ready for use.


 

construction and working of a torque convertor in an automobile | torque convertor a type of fluid coupling

Torque converter an Alternate to Gear Box

Torque converter is a type of fluid coupling that uses a fluid to transmit turning effort from the one shaft to another. It is a device which performs a function similar to that of a gear box, namely, to increase the torque while reducing the speed. A gear box provides only a small number of fixed ratios, but the torque converter provides a continuous variation of ratio from the lowest to the highest.The torque convertor is somewhat similar to a fluid fly wheel, but differs from it in one aspect, namely it has three principal components instead of only two.

01 - construction and working of a torque convertor in an automobile - TORQUE CONVERTER OF AN AUTOMOBILE AN ESSENTIAL PART

Components of a Torque converter

(i) The driving element or impeller or pump which is connected to the engine.

(ii) The driven element or rotor or turbine which is connected to the propeller shaft and

(iii) The fixed element or reaction member or stator which is fixed to the frame.

The fixed element is responsible to cause a change of torque between input and output shafts. The fluid flywheel does not have any fixed member, as such cannot produce any change of torque.

How does a Torque Converter Works

The three element torque converter can be seen in the picture. In the torque converter, torque multiplication take place in the following way. The oil leaving vanes hits the stator vanes. This oil is redirected into the pump vanes in a direction which helps the pump operation. This oil is again thrown into the turbine by the pump. In fact, this is a continuous process. The fluid pushing repeatedly on the turbine vanes increases the torque on the turbine. In many designs of torque converters, the torque almost doubled. However, as the speed of the turbine approaches the speed of the pump, the increase in torque falls of gradually till it becomes 1:1. At this stage, the oil starts striking the rear faces of the vanes in the stator, thus making the stator to turn. Now the stator does not take part in torque converter action. Under these conditions, the torque converter simply acts as a fluid fly-wheel.

01 - TORQUE CONVERTER OF AN AUTOMOBILE - construction and working of a torque convertor in an automobile

Working Principle of a torque converter

The over running clutch (freewheeling device) used for mounting the stator. The spring loaded rollers in the freewheel allow the stator to freewheel when the oil starts striking the rear of the stator vanes. On the other hand, when the oil strikes the front of the stator vanes, it attempts to rotate the stator in the opposite direction. But this action locks up the freewheeling device and thus holds the stator stationary. Under such condition, the stator acts as a reaction member, and directs the oil leaving the turbine trailing edges in the proper direction before it enters the pump vanes.