Efficiency of DC Generator

Efficiency is simply defined as the ratio of output power to the input power. Let R be the total resistance of the armature circuit (including the brush contact resistance, at series winding resistance, inter-pole winding resistance and compensating winding resistance). The efficiency of the DC generator is explained below in the line diagram: I is …

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Applications of DC Machines

In the present day world, electrical energy is generated in bulk in the form of an alternating current. Hence, the use of DC machines, i.e., DC generators and motors are very limited. They are mainly used in supplying excitation of small and medium-range alternators. The Industrial Applications of DC Machines are in Electrolytic Processes, Welding …

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Losses in DC Machine

The losses that occur in a DC Machine is divided into five basic categories. The various losses are Electrical or Copper losses (I2R losses), Core losses or Iron losses, Brush losses, Mechanical losses, Stray load losses. These losses are explained below in detail. Contents: Electrical or Copper losses Magnetic Losses or Core Losses or Iron …

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Characteristic of DC Generators – Separately Excited Self Excited And Compound Generator

Characteristic is the graph between the two dependent quantities. It shows the steady-state characteristic of DC generators. The characteristic of the DC generators explains the relations between the loads, excitation and terminals voltage through the graph. Following are the three important characteristics of a DC Generator. Magnetization Characteristic This characteristic gives the variation of generating …

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Starting of DC Motors

A starter is a device to start and accelerate a motor. A controller is a device to start the motor, control and reverse the speed of the DC motor and stop the motor. While starting the DC motor, it draws the heavy current which damages the motor. The starter reduces the heavy current and protects the …

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Methods of Improving Commutation

There are three main methods of Improving commutation or obtaining sparkles Commutation. These are Resistance Commutation and Voltage Commutation and Compensating Winding. Further, the voltage commutation consists of another two methods which are used to produce the injected voltage, named as commutating poles or interpoles and Brush Shift. The following methods of Improving Commutation are …

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Speed Regulation of DC Motor

If the load is applied to the DC motor or machine, the speed of the motor decreases automatically. Thus to maintain the constant speed, the difference between no-load and full-load speed (called Speed Regulation) should be maintained very less. The motor is said to be at good regulation if they maintain the constant speed at variable …

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Commutation in DC Machine

The currents induced in the armature conductors of a DC generator are alternating in nature. The change from a generated alternating current to the direct current applied involves the process of Commutation. When the conductors of the armature are under the north pole, the current which is induced flows in one direction. While the current …

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