Permanent magnet motors are similar to conventional DC motors except the use of permanent magnet to produce flux instead of field winding. The use of high energy permanent magnet in the motors which advances in the field for the purpose of simplicity and low initial cost has led to the formation of new class of […]
What is Permanent Magnet DC Motor (PMDC Motor)? Construction, Diagram & Applications Read More »
Figure 1: Switched Reluctance Motor. Switched Reluctance Motor can be operated on DC as well on AC supply. It uses no brushes nor any permanent magnet. It is a specialized type variable reluctance stepper motor. It has less number of poles.
Plugging is the simplest type of braking which involves re-connection of motor to supply in such a way that motor develops torque in opposite direction to the movement of rotor system, speed will decrease till zero speed is reached where mechanical brakes are applied and then it will accelerate in opposite direction. This method is
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A current transformer (CT) is nothing but a coil wound on a toroidal core. When a large current carried by a conductor is to be measured, it is advisable to avoid the direct connection of ammeter in this high current circuit. For this purpose a current transformer is used. Fig. 1 : Connection of Current
The three phase autotransformer is a combination of three single phase autotransformers. It has three windings, one per phase. Fig. 1 : 3 Phase Autotransformer.
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Swinburne’s test is the simplest indirect method to determine the efficiency of D.C machine. In this test the no- load losses are measured separately and from their knowledge, efficiency at any desired load can be predetermined in advance. Figure 1: Arrangement of Swinburne’s test.
What is Swinburne’s Test of DC Motor? Theory & Diagram Read More »
Retardation Test is used for finding the efficiency of shunt wound DC machines. In this test, the rotational losses or stray losses are measured and from their knowledge efficiency at any desired load can be determined. Figure 1: Arrangement of Retardation Test.
What is Retardation Test (or Running Down Test) of DC Motor? Theory & Circuit Diagram Read More »
Figure 1: Arrangement of Brake Test. Brake test is a direct testing method used to find the efficiency of a DC motor. The arrangement for performing brake test on a DC motor is shown in figure (1).
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The different methods of speed control of DC shunt motor are, Armature control method Field control method Ward-Leonard method. Armature Control Method
Speed Control for DC Shunt Motor – Methods & Diagram Read More »