Synchronous Machines and Electromagnetic Principles

An electromotive force (emf) is generated in a conductor when it moves through a magnetic field.

A force or torque is exerted on a current-carrying conductor placed in a magnetic field due to the interaction of the magnetic fields.

The process of converting mechanical energy into electrical energy.

The process of converting electrical energy into mechanical energy.

The windings that create the main magnetic field in a machine.

The windings where the main voltage is induced in a generator or the current flows in a motor.

The windings on the rotating part of a machine.

The windings on the stationary part of a machine.

A winding where coils under a pole are arranged in a concentric shape. Imagine a spiral staircase with each layer being a coil.

A winding type where coils overlap consecutively, like chain links, with connections made between them. For each coil, the end connection is made to the start of the next coil.

A winding where coils are always connected in a forward direction, making a continuous wave-like path. The connections are 'end-to-start' but with a leap.

The angle measured in degrees that represents one complete cycle of induced electromotive force (EMF) in a conductor as it passes through a pair of poles. It is a measure of electrical change.

The distance between the neutral axis (axis of symmetry) of adjacent poles. It's basically the space/gap between two poles.

The distance between the two active sides of a single coil. It is the length of the coil path.

The distance between the center points of two consecutive slots or teeth on the armature. It is the space occupied by a single slot.

The angle or space on the pole face where the coil sides of the same phase are located. It's the spread of coils with the same electrical phase.

The speed of the rotating magnetic field created in the stator of an AC motor.

The rotor of a synchronous motor locks itself to the rotating magnetic field of the stator, causing it to rotate at the same speed, maintaining synchronous speed.

The stationary part of an AC motor containing coils of wire that carry current, creating the rotating magnetic field.

The rotating part of an AC motor that interacts with the magnetic field produced by the stator and is responsible for mechanical output.

The rotating magnetic field travels at a specific speed in a synchronous motor. This speed is determined by the frequency of the AC power supply and the number of poles in the stator.

A type of synchronous machine with smooth cylindrical rotor that rotates at the same speed as the rotating magnetic field, achieving a smooth, sinusoidal flux distribution and a high operating speed.

A type of synchronous machine with salient poles protruding from the rotor, designed for lower operating speeds.

The speed at which the rotating magnetic field in a synchronous machine revolves, determined by the frequency of the stator winding and the number of poles.

A fictitious reactance accounting for the combined effect of leakage reactance and armature reaction reactance, influencing the machine's performance.

The vector sum of armature resistance and synchronous reactance, representing the total opposition to current flow in the machine.

A test used to experimentally determine the synchronous impedance of an alternator by measuring the field current needed to achieve rated current under short-circuit conditions.

The ratio of field current needed for rated voltage on open-circuit to the field current needed for rated current on short-circuit, a measure of the machine's excitation characteristics.

A characteristic curve showing the relationship between field current and the open-circuit terminal voltage of an alternator.

Energy loss in a magnetic material due to the reversal of its magnetization. It occurs when the magnetic field within the material changes direction.

The constant that quantifies the energy loss per unit volume of magnetic material during one magnetic reversal. It depends on the material's characteristics.

Loss due to the flow of eddy currents within a conductor when the magnetic field changes. These currents are induced by the changing magnetic field.

The coefficient that determines the magnitude of eddy current loss. It's influenced by the material's properties.

Losses caused by friction in a rotating field system, including air friction and friction at bearings.

Additional losses in a synchronous machine, mainly caused by distortion of the magnetic field under load and losses in insulation.

The ratio of the output power to the input power of a synchronous generator.

Laminating the core material into thin sheets reduces eddy current losses significantly.

The magnetic field generated by the rotor interacts with the magnetic field of the stator, creating a force that rotates the rotor.

A simplified representation of a synchronous motor's electrical behavior, showing the relationship between the applied voltage, back emf, armature current, and synchronous reactance.

The voltage induced in the rotor winding due to its rotation in the stator's magnetic field. It opposes the applied voltage, similar to how a battery's voltage opposes current flow in a circuit.

The voltage in the armature circuit that drives the armature current. It is the difference between the applied voltage (V) and the back EMF (Ef).

The synchronous motor is operating with the right amount of magnetic field excitation. The resultant voltage (Er) is equal to the applied voltage (V).

The synchronous motor has a weaker magnetic field than needed. The resultant voltage (Er) is less than the applied voltage (V).