E-Throttle

Insulation Resistance All know that the resistance of a pure insulation is infinity. But to no extend we can make a pure insulation. So we have a small leakage current to flow through insulation depending upon the voltage applied. Thus as the result we get a resistance value in the range of Mega Ohms(MΩ) or Giga Ohms(GΩ).   Here the applied voltage is DC. We have separate kit for injecting the DC voltage. Usually that equipment is known as megger. The two windings are connected as in the diagram above and Megger is used to measure the insulation resistance. It applies a high voltage normally 500V or 1kV for time period of minimum 30 seconds to One minute and the respective resistance are noted down. Usually for a new transformer, result value will be in Giga Ohms(GΩ). During the ageing, deposition of dust, moisture and other unwanted particles can cause the megger value to reduce. So to gain the resistance back to normal, the dust deposited should be removed, moisture shoul...

We know electricity as the most dangerous and powerful source of energy existing in nature. So to protect humans from it's contact, we need some material. A kind of material which opposes the flow of heat, light, sound and electricity is known as an insulator. In other words, these are the material which have a high value of resistance beyond few, 100 mega Ohms. So practically no flow of current occurs through these types of materials. Stephen Gray was the one to introduce conduction of electrons to the world. he also stated the different materials have different property towards conduction. When he used the metal as conductor, on the other side used silk as an insulator because it showed high resistance towards electric conduction. Later it was David Brook who altered the old style of insulator and used it for his telegraph lines during 1864 to 1867.  His insulator had a thick metal casing around blown glass, the assembly was held together with molten sulfur. Out of the tube ex...