Difference between AC and DC Relay

What is a relay Coil?  The relay  coil has many turns of copper wire wound around a bobbin in which iron core is situated. The resistance of the coil depends on the length of the wire and cross-sectional area of wire. When the  voltage is applied across the coil, the coil set up a magnetic field … Read more

Windage losses in Electric Machines

    When any rotating machine rotates, the air surrounding to the rotor offer resistance and the air resistance try to slow down the rotational force. The extra energy an electrical machine takes from the power source to overcome this opposition. The loss caused by the air friction between rotor and surrounding air is called … Read more

What is meaning of 5P20 in current transformer?

    There are three types of current transformers which are used for various application in; 1. Metering Purpose 2. Protection Purpose 3. Special Protection Purpose The particular class of CT is used for specific application. if one class of CT is used for other application the protection or measuring reliability is lost. If the metering … Read more

Losses in DC Machine- Types of Losses

losses in dc machine

Electric rotating machines are used for conversion of energy. The motor converts electrical energy into mechanical energy and, the generator converts mechanical energy into electrical energy. During energy conversion, the input energy in one form can not be fully converted into output energy in another form . The difference in the output energy and input … Read more

DC Motor or Direct Current Motor

What is DC Motor ?   The electric motor converts electrical energy into mechanical energy. The electric motor is used to drive the mechanical loads. The electric motor operated by ac supply is called ac motor and, the electric motor operated by dc supply is called the dc motor.     The DC motor and … Read more