Deepakkumar Yadav
Schering Bridge There are various methods for the measurement of capacitance and di-electric loss. Schering Bridge method is very important and popular method to determine these terms. In this method imperfect capacitor can be compared with a perfect capacitor. (C2 is compared with C1). The imperfect capacitor is represented by its equivalent loss free capacitor C in … Read more
Measurement of Dielectric Constant and Loss Factor Introduction to Dielectric Loss Dielectric constant is also called relative permittivity of the insulating material. Many of the insulating materials have dielectric constant more than unity. These materials show dielectric loss when subjected to AC voltages. Dielectric constant as well as dielectric loss depends on magnitude of voltage … Read more
Loss of Charge Method to Measure Resistance and to Calculate the Resistivity of a Specimen Refer Figure in this figure when B is taken on position 1, the voltage is applied and circuit is charged. But after this if the switch B is taken to position 2, it is disconnected from the supply and the capacitance … Read more
Measurement of Resistivity by Wheatstone Bridge Method (For Liquid Insulators) For liquid insulators the measuring unit (cell) has the following construction. Procedure to find resistivity of a liquid insulator As explained in the previous case of solid insulation, the experimental set up w the same i.e. H.V stable supply voltage to the circuit of Wheatstone … Read more
Measurement of Resistance (Resistivity) by Simple DC Galvanometer Galvanometer is first calibrated by use of standard resistance of the values 10 MΩ with tolerance ± 0.5 to ± 1 %. Calculations The resistance of the specimen (RP) is given by RP = V / D x G Where D = deflection in cm with specimen G = Galvanometer sensitivity A … Read more
Measurement of D.C. Resistivity D.C resistivity can be measured by various methods such as using Galvanometer using D.C. Amplifier and using wheatstone bridge. Prior to study the above methods, let us take the idea of shape of specimen of insulation, and electrode system.Specimen and Electrode For facilitating calculation of D.C. resistivity, the shape of specimen … Read more
Aim of Testing the Insulation Properties (Non destructive Testing) Q. What non destructive testing of insulating materials ? State briefly the characteristics of these methods. Prior to use the insulating materials as the part of the equipment, its quantity is to tested by taking a sample of it so that it shall not create a … Read more
Capacitance Voltage Transformer The high voltage measurement is possible by utilizing the concept of resonance. The setup used for it is often known as capacitance voltage transformer. The capacitance voltage transformer is shown in Figure A its equivalent circuit is shown in Figure B.It consists of C1 – High voltage capacitance (value is in few thousand … Read more
High AC voltage Measurement Following methods can be used Electrostatic Potential divider Potential transformer (Voltage Transformer) Electrostatic Sphere gap Impulse voltage Measurement Following methods can be used : 1. Voltage dividers. (a) Resistance with CRO (b) Capacitances and current, voltage transformer (c) RC 2. Peak voltmeters 3. Sphere gap For RMS value measurement methods used … Read more
Measuring Capacitors / Peak Voltage Measurement According to Chubb and Fortescue As opposed to sphere gaps, the circuit suggested by Chubb and Fortescue in 1913 is capable of measuring the peak value of a high AC voltage continuously and accurately. Figures A and B shows the circuit with its current and voltage curves. (a) Circuit … Read more