Hopkinson’s Test is also known as Regenerative Test, Back to Back and Heat Run Test. In Hopkinson Test, two identical shunt machines are required which are coupled both mechanically and electrically in parallel. One is acting as a motor and another one as a generator. The input to the motor is given by the supply mains. …
DeMorgan’s Theorem is mainly used to solve the various Boolean algebra expressions. The Demorgan’s theorem defines the uniformity between the gate with the same inverted input and output. It is used for implementing the basic gate operation likes NAND gate and NOR gate. The Demorgan’s theorem mostly used in digital programming and for making digital …
Electrical Braking is usually employed in applications to stop a unit driven by motors in an exact position or to have the speed of the driven unit suitably controlled during its deceleration. Electrical braking is used in applications where frequent, quick, accurate or emergency stops are required. Electrical Braking allows smooth stops without any inconvenience …
Like OR and AND operation, the NOT Operation is also an important function in the digital electronic circuit. It is denoted by a bar. The binary not operation is also known as not function or complement function or bit invert function. The not operation has only one input and one output. The input and output …
The OR Operation is also one of the functions in a digital logic circuit. It is represented by a plus (+) sign. For example: x + y = z which is read as “x or y is equal to z”. The truth table for the OR operation is shown in the table below: The truth …
The three Binary Operations are AND Operation, OR and NOT Operation. A binary logic deals with variables having distinct values like true or false, yes or no, hot or cold, high or low, etc. In a digital system design, assigning the values 1 or 0 to these two values of the variables because digital algebraic …
In Plugging or Reverse Current Braking the armature terminals or the supply polarity of a separately excited or shunt motor when running are reversed. Therefore, in plugging the supply voltage V and the induced voltage Eb which is also called back EMF will act in the same direction. Thus, during plugging the effective voltage across …
In Dynamic Braking, a braking resistor Rb is connected across the armature as soon as the DC motor is disconnected from the supply mains. The motor now works as a generator, producing the braking torque. For the braking operation in Dynamic Braking, the motor is connected in two ways. Firstly the separately excited or shunt …
Dynamic Braking or Rheostatic Braking of DC Motor Read More »
The dc motor converts mechanical power into dc electrical power. One of the most important features of the dc motor is that their speed can easily be control according to the requirement by using simple methods. Such type of control is impossible in an AC motor. The concept of speed regulation is different from the …
Speed Control of DC Motor: Armature Resistance Control and Field Flux Control Read More »
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 …
