Swinburne’s Test is an indirect method of testing of DC machines. In this method, the losses are measured separately and the efficiency at any desired load is predetermined. Machines are tested for finding out losses, efficiency and temperature rise. For small machines direct loading test is performed. For large shunt machines, indirect methods are used …
In Regenerative Braking, the power or energy of the driven machinery which is in kinetic form is returned back to the power supply mains. This type of braking is possible when the driven load or machinery forces the motor to run at a speed higher than the no-load speed with a constant excitation. Contents: Applications …
Ward Leonard Method of speed control is achieved by varying the applied voltage to the armature. This method was introduced in 1891. The connection diagram of the Ward Leonard method of speed control of a DC shunt motor is shown in the figure below. Contents Torque and Power Characteristic Advantages of Ward Leonard Drives Drawbacks …
Ward Leonard Method Of Speed Control Or Armature Voltage Control Read More »
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 …
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 …
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 …
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 …
Characteristic of DC Generators – Separately Excited Self Excited And Compound Generator Read More »
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 …
The Power Flow Diagram is used to determine the efficiency of a generator or motor. In the below figure of power flow diagram of DC Generator, it is shown that initially the mechanical power is given as an input which is converted into electrical power, and the output is obtained in the form of electrical …
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 …
