Current Transformer – Construction, Phasor and Errors

  Current transformer are widely used for measuring the high current. The Current transformer steps down high value of current to low value which measuring instrument can read. If 2000 Amperes current to be read by a meter, it is not possible to read because a amall shunt resistance of high power rating in parallel … Read more

Why is armature of alternator connected in Star not in Delta?

  The alternator armature winding must be protected for earth fault. The earth fault protection scheme for alternator whose armature winding is connected in delta is more complicated as neutral is not available in the case of delta connected srmature. An open delta transformer is required to be installed for detecting the earth fault in … Read more

EMF Equation of Alternator and AC Generator

An alternator or AC generator produces AC supply. In other words, the generator or alternator  converts mechanical energy into electrical energy. The rotor rotates at the synchronous speed. Therefore, we call AC generator as a  synchronous generator. On the basis of  design, the alternators are classified into two categories. Salient pole type Cylindrical rotor type. … Read more

Thermistor: Definition,working principle and applications

What is a Thermistor? A thermistor is a type of thermal resistor whose electrical resistance increase or decrease with change in temperature.Thus, the thermistors are thermally sensitive resistance whose resistance changes with  change in the thermistor body temperature. We will discuss about the working principle of thermistor. How  PTC and NTC thermistor function and  what … Read more

Direction of Rotation of DC Motor

  There are many applications where direction of the motor is required to be reversed. The applications includes forward/reverse belt drive control, travel drive etc.   The direction of DC motor can be reversed by reversing the direction of torque of the motor. When motor exerts torque in clockwise direction it rotates in the clockwise … Read more