Generally, Swinburne's test is the most popular testing method of dc machine to determine losses and efficiency. It is an indirect method of testing a dc machine performed without actually loading the machine. Since it is a n…
In the last article, we have seen Swinburne's Test of dc machine, where the efficiency and losses are determined without applying actual load on the machine. It is an indirect method of testing a dc machine. Now let us see an…
Armature winding is the essential part of any electrical machine (motor or generator). The emf or voltage will be induced in the armature winding in the case of a generator, while it produces torque to rotate the shaft in the cas…
A dc motor is basically self-starting, it doesn't require any starting device. But in order to start the motor in a desired safe way, there is a need for an external device called 'Starter'. A dc motor can start witho…
In a recent article, we have seen the construction and working principle of a three-point starter. The disadvantage of a three-point starter is that due to the series connection of field winding with the no-volt coil (NVC). In or…
Dc motors are widely used in various applications like variable-speed drives, constant-speed drives, and many more. For selecting a type dc motor for a particular application it is very important to study the characteristics of v…
In a dc machine, the given input energy will be not equal to output energy i.e., the output energy will be always less than the input energy, thereby reducing the efficiency. The whole electrical input is not available at the mec…
At starting when a rated voltage is applied across the stationary armature terminals of the dc motor, it draws more current comparatively greater than the rated current. When such heavy currents pass through the armature windings…
Basically, there is no difference in the construction of a dc motor and dc generator. A dc motor gives a mechanical output with input as a dc supply while the dc generator gives dc electrical output with mechanical input. Similar…
It is seen that emf induced in the armature conductors of a dc generator is alternating in nature. The frequency of the induced emf alternates with a frequency corresponding to the product of the speed and the number of pairs of …
In this method, the speed control of the dc motor is achieved by controlling the voltage applied across the armature terminals. It is introduced by the scientist sir Henry Ward Leonard in 1891 and named as a 'Ward Leonard Spe…
