Mechanical Guru's

PROPORTIONAL CONTROL SYSTEM Proportional control action In a proportional control action, there is a continuous linear relation between the output m (t) and the actual error signal e (t). Evidently the control valve or the regulating unit can take up any position right from the fully open to fully closed. Depending upon the shift of the measured variable from the desired value, an adjustment is made of the amount of energy supplied (i.e., the manipulated variable) to the process or plant. The change in the valve position is proportional to the amount of deviation and is not affected by the rate or duration of the deviation. The proportional control follows the law:                                                   ...

SELECTING AN MEASURING INSTRUMENT THE SELECTION OF AN INSTRUMENT FOR A SPECIFIC MEASUREMENT APPLICATION REQUIRES THE CONSIDERATION OF SEVERAL FACTORS THE FOLLOWING BEING CERTAINLY FUNDAMENTAL TO ENTIRE PHILOSOPHY OF MEASUREMENT AND INSTRUMENT SELECTION. MAXIMUM AND MINIMUM VALUES THE INPUT VARIABLES ARE EXPECTED TO ASSUME - THE INSTRUMENT RANGE MUST EQUAL TO THE EXPECTED RANGE OF VARIABLE TO BE MEASURED. EXCESSIVE INSTRUMENT RANGE MEANS A LOT OF READABILITY.FOR A WIDE RANGE IN THE VARIABLE, MULTIPLE RANGE OF INSTRUMENT ARE DESIRED. NATURE OF THE INPUT SIGNAL -  IS IT CONSTANT OR TIME DEPENDENT? IF TIME VARIANT, THEN WHETHER VARIATION IS PERIODIC, TRANSIENT OR RANDOM. FOR TRANSIENT MEASUREMENT, IT IS TO BE ENSURED THAT NATURAL FREQUENCIES AND TIME CONSTANTS ARE PROPERLY SELECTED. NON INTERFERENCE WITH MEASURING SYSTEM - THE BASIC PRINCIPAL OF MEASURING IS THAT THE ACT SHOULDN'T AFFECT THE QUANTITY BEING MEASURED. OUR JOB IS TO SEE THAT THE INSTRUMENT OF...

MEASUREMENT AND ITS TYPE MEASUREMENT: MEASUREMENT IS USED TO TELL US THE LENGTH, THE WEIGHT, THE TEMPERATURE, OR A CHANGE IN ONE OF THESE PHYSICAL ENTITIES OF A MATERIAL. IT IS THE RESULT OF AN OPINION FORMED BY ONE OR MORE OBSERVERS ABOUT THE RELATIVE SIZE OR INTENSITY OF SOME PHYSICAL QUANTITY. THE OPINION IS FORMED BY THE OBSERVER AFTER COMPARING THE OBJECT WITH A QUANTITY OF SAME KIND CHOSEN AS A UNIT, CALLED  STANDARD. THE RESULT OF MEASUREMENT IS EXPRESSED BY A NUMBER REPRESENTING THE RATIO OF THE UNKNOWN QUANTITY TO THE ADOPTED STANDARD. FOR EXAMPLE, 10 CM LENGTH OF AN OBJECT IMPLIES THAT THE OBJECT IS 10 TIMES AS LARGE AS 1 CM; THE UNIT EMPLOYED IN EXPRESSING LENGTH. TYPE OF MEASUREMENT MEASUREMENTS ARE DIVIDING IN TO THREE CATEGORIES DIRECT AND INDIRECT MEASUREMENTS DIRECT MEASUREMENTS THE VALUE OF THE PHYSICAL PARAMETER (MEASURAND) IS DETERMINED BY COMPARING IT DIRECTLY WITH REFERENCE STANDARDS. THE PHYSICAL QUANTITIES LIKE MASS, LENGTH, AND TI...

MAINTENANCE AND ITS TYPES MAINTENANCE:- MAINTENANCE INVOLVES KEEPING THE WORKPLACE, ITS STRUCTURES, EQUIPMENT, MACHINES, FURNITURE AND FACILITIES IN GOOD REPAIR AND OPERATING EFFICIENTLY AND SAFELY BREAKDOWN MAINTENANCE IT MEANS THAT PEOPLE WAITS UNTIL EQUIPMENT FAILS AND REPAIR IT. SUCH A THING COULD BE USED WHEN THE EQUIPMENT FAILURE DOES NOT SIGNIFICANTLY AFFECT THE OPERATION OR PRODUCTION OR GENERATE ANY SIGNIFICANT LOSS OTHER THAN REPAIR COST. PREVENTIVE MAINTENANCE IT IS A DAILY MAINTENANCE (CLEANING, INSPECTION, OILING AND RE-TIGHTENING), DESIGN TO RETAIN THE HEALTHY CONDITION OF EQUIPMENT AND PREVENT FAILURE THROUGH THE PREVENTION OF DETERIORATION, PERIODIC INSPECTION OR EQUIPMENT CONDITION DIAGNOSIS, TO MEASURE DETERIORATION. IT IS FURTHER DIVIDED INTO PERIODIC MAINTENANCE AND PREDICTIVE MAINTENANCE. JUST LIKE HUMAN LIFE IS EXTENDED BY PREVENTIVE MEDICINE, THE EQUIPMENT SERVICE LIFE CAN BE PROLONGED BY DOING PREVENTIVE MAINTENANCE. ...