Tricky but Easy Electrical Engineering!
The rating of transformer is given in terms of its kVA, HV/LV voltage and phase rotation (for three phase transformer). To calculate the rating of the transformer for both single phase and three phase, the load required to be fed and voltage at which load is to be fed must be known or should be … Read more
Rotating magnetic field is magnetic field which rotates in space about some point or axis. The North and South poles continuously rotates with a specific speed, called synchronous speed. All poly phase electrical machines are associated with rotating magnetic field in the air gap. Therefore, an understanding of rotating magnetic field produced by poly phase … Read more
Induction Motor works on the principle of electromagnetic induction. The three phase input power supplied to stator terminal is converted into mechanical power at the shaft output. This conversion of energy takes place through magnetic coupling between stator produced rotating magnetic flux and rotor bars. The power transfer from stator to rotor takes place through … Read more
Air gap in rotating electrical machine is a coupling medium to transfer electrical energy from stator to the rotor or vice versa. It is also required for free rotation and proper cooling of the machine. Generally air gap length is kept as low as possible due to several reasons. But if we compare the air … Read more
Direct Axis Synchronous Reactance A direct axis quantity is one whose magnetic effect is along the field pole axis. Field pole axis is also known as direct axis. Based on this fact, a direct axis synchronous reactance is defined as the reactance offered to the armature flux when the peak of armature mmf is directed … Read more
Synchronous Machine is electromechanical equipment in which the speed of rotating part i.e., Rotor, is equal to the speed of rotation of magnetic flux. The speed of rotation of magnetic flux is called synchronous speed. That is why these types of equipment is called synchronous machine. This article outlines the constructional detail and type of … Read more
Definition Short Circuit Ratio, or SCR, is the ratio of field current required to generate rated voltage under open circuit condition, to the field current required to circulate the rated armature current under three phase short circuit condition. It is an important quantity of synchronous machine which helps in estimation of operating characteristics. It is … Read more
Zero Power Factor Characteristics Zero Power Factor Characteristics (zpfc) of synchronous generator is a plot between the armature terminal voltage and field current for a constant value of armature current and speed. A purely inductive load is connected across the generator terminal to achieve zero power factor and zpfc. Zero power factor characteristics along with … Read more
The main purpose of compensating winding is to nullify the effect of armature reaction on the main field flux under the pole faces in DC machine. Due to the effect of armature reaction mmf, the flux distribution under the pole faces is distorted which leads to poor commutation and flashover. When a DC machine is … Read more
DC motor is an electromagnetic device which converts electrical energy into mechanical energy. DC power input is converted into mechanical power at the shaft motor. This article describes the construction of DC motor. There is no difference in the construction of DC Motor and Generator. A DC Motor can also be used as DC generator … Read more