Deepakkumar Yadav
Procedure for Cleaning, Washing and Drying of Insulation & Describe the Vacuum Impregnation Method of Varnishing Q. Explain the procedure for cleaning, washing and drying of insulation and describe the vacun impregnation method of varnishing. Methods of cleaning insulation : The failure of insulation takes place due to absorption of moisture. Oil, dust, dirt, excessive … Read more
Internal Causes of Failure and Abnormal Options of Equipments Q. What are the Internal causes of failure and abnormal operation of equipments. Internal Causes : In some unavoidable situation the machine may have to be run “over loaded” for a longer-period which causes temperature rise beyond the permissible limit. During normal working shot-circuit may occur … Read more
Mechanical and Electrical Faults and Causes in Case of Electrical Machines Q. list out the mechanical and electrical faults and causes in case of electrical machines. Mechanical Faults : Sr. No. Fault Reasons Remedial measures 1 Bent shape Drawback in shaft coupling machine to machine or machine to load shaft. Concentric coupling very tight fitting … Read more
Uses of Tool Multimeter Q. Describe the use of following tool : Multimeter. This meter is basically a P.M.M.C. instrument. The coil winding of the movement is very small. A shunt resistance is used for the protection and range extension. It can be used to measure current, voltage, resistance, etc., and hence it is also … Read more
Uses of Earth Tester Q. Explain the use of : Earth Tester. The resistance of earth can also be measured by an earth tester. The indication of the earth tester depends up on the ratio of the voltage across the pressure coil and the current through the coil. The deflection of its pointer indicates the … Read more
Troubles in Electrical Insulation and cables Q. List common troubles in electrical insulation and cables. Mechanical failure Dielectric failure Thermal cause of failure Chemical failure Failure due to ageing
Uses of Dial Indicator Q. Explain the use of : Dial Indicator By this indicator the shape (whether true or damaged) of various rotating parts of machine such as shafts, rotors, commutators are checked. These consists of system of interlink livers / Gear wheels. By this the small moments are magnified to enable to read … Read more
Various Methods of Heating the Machine Q. Explain the various methods of heating the machine. The various methods of heating the machine are as follows : External heat : It is the method of drying insulation most frequently used. The various methods of applying external heat are : Baking in the oven : It is … Read more
Causes of Heat in Bush-bearings of Electrical Machines Q. What are the causes of heat in bush-bearings of electrical machines ? Following are the causes of heat in bush-bearings : Worn out bearings / sleeves. Worn out shaft. Loss of lubrication. Mis-alignment of shaft pulleys couplings. Heavy vibration and noise due to uneven air-gap in … Read more
Factors on Which Life of Insulation Depends Q. State the factors on which life of Insulation depends. Temperature : The insulation resistance decreases with temperature. The dielectric loss increase with temperature. The resistivity of the insulating material decreases by increse in temperature. The same can be expressed as Rt = R0 (1 – α0t ), … Read more