What are Synchronous Motors?Synchronous motor definitionA synchronous motor is an AC motor in which the rotation of the rotor is synchronized with the frequency of the supply current.Constant speed operationSynchronous motors operate at a constant speed called synchronous speed, which is determined by the number of poles of the motor and the frequency of power supply.N= The Synchronous Speed (in RPM – i.e. Rotations Per Minute)f = The Supply Frequency (in Hz)p = The number of PolesThe structure

What is Armature Reaction in DC Machine?Armature reaction definitionThe armature reaction in a DC motor is the effect of the armature magnetic flux on the main magnetic field, changing its distribution and intensity.Cross magnetizationCross-magnetization due to the armature current affects the magnetic field by moving the magnetic neutral axis, resulting in efficiency problems.Brush ShiftA natural solution to the problem appears to shift the brushes along the direction of rotation in generator a

What are the Methods of Improving Commutation?Commutation definitionCommutation is the process of reversing the current in the coil to keep the motor running efficiently.There are three main methods of improving commutation. Resistance commutation E.M.F. commutation Compensating windingsResistance CommutationIn this method of commutation we use high electrical resistance brushes for getting spark less commutation. This can be obtained by replacing low resistance copper brushes with high resistan

What is Commutation in DC Machine?Commutation definitionCommutation in a DC motor is defined as the process of converting alternating current generated in the armature winding to direct current using a commutator and a fixed brush.Continuous contactThis process requires continuous contact between the commutator segment and the brush to maintain the current conversion.Ideal commutationIdeal commutation means that the current is reversed within the commutation cycle to avoid sparks and damage.Curr

What is a DOL Starter ?DOL Defines an initiatorDOL Starter (Direct On Line Starter) is a method of starting a three-phase induction motor. In the DOL starter, the induction motor is directly connected to its 3-phase power supply, and the DOL starter applies the full line voltage to the motor terminals. The motor is protected even when connected directly to the power supply. DOL motor starters include protection and, in some models, condition monitoring. The following is the wiring diagram of the

What is a Star Delta Starter?Star triangle starter setThe star triangle starter is used to start a three-phase induction motor by starting in a "star" configuration and then switching to a "triangle" after reaching a certain speed, thereby minimizing initial electrical overload.Circuit diagramThe circuit includes a TPDP switch that helps to change the motor connection from a star to a triangle, thereby effectively controlling current and torque during startup. For that let us consider,VL = Suppl

What is Ward Leonard Method of Speed Control?Vaud Leonard method definitionThe Vaud Leonard method is defined as a speed control system using a DC motor with a variable voltage provided by an electric generator set.Principles of the Vaud Leonard methodThe system involves a DC motor (M1) that is driven by another motor (G) that is driven by another motor (M2) that controls the speed by adjusting the output voltage of the generator.Advantage It is a very smooth speed control system over a very wid

What is Phasor Diagram for AC Series Motor?Phasor diagram definitionThe phasor diagram illustrates the phase relationship between different electrical quantities in AC series motors.Characteristics of AC series motor Power factor characteristic Velocity current characteristic Torque current characteristics Torque speed characteristics Power output characteristicPower factorA high power factor requires low reactance and back electromotive force, which decreases when overloaded.Velocity and back e

What are AC Series Motor?Ac series motor definitionThe AC series motor is an improved version of the DC series motor, suitable for operation under alternating current (AC).Modify requirementNecessary modifications include reducing eddy currents and increasing the power factor to improve the performance of AC power supplies.Compensation winding typeConduction compensated motorThe conductive compensation motor is characterized by a compensation winding in series with the armature, which is located

What is the Schrage Motor Operation Principle?Schrage Motor DefinitionA Schrage motor is defined as a combination of a wound rotor induction motor and a frequency converter with primary, secondary, and tertiary windings.Operation PrincipleAt standstill, three-phase currents in the primary winding produce a rotating field. This rotating field cuts the secondary winding at synchronous speed (ns).Therefore according to Lenz’s law the rotor will rotate in a direction so as to oppose the cause i.e. t