What are the common features of rotating electrical machines?

The rotating machines have magnetic poles. And the torque is generated by a set of magnetic forces of attraction and repulsion between magnetic poles of the stator and rotor. The scheme of the rotating machines, which shows the magnets of rotor and stator. The stator magnet is static, the rotor magnet is moving.

What type of rotating machine produces power?

A direct-current (DC) generator is a rotating machine that supplies an electrical output with unidirectional voltage and current. The basic principles of operation are the same as those for synchronous generators.

What is the rotating part of the machine called?

One part of the machine is stationary and is known as the stator or frame; the moving or rotating part is known as the rotor.

What are the main dimensions of a rotating machine?

In rotating machine the active part is cylindrical in shape. The volume of the cylinder is given by the product of area of cross section and length. If D is the diameter and L is the length of cylinder, then the volume is given by πD2L/4. Therefore D and L are specified as main dimensions.

What is electrical rotating machine?

Electrical machines are usually rotating devices creating electromagnetic torque due to the magnetic coupling field. The machines perform electromechanical conversion of energy; thus, they are called rotational converters. The stationary part of rotating machines is called stator.

Is a transformer a rotating machine?

The transformer is a static device having primary and secondary windings. In rotating machines, there are two parts: the stator and the rotor. Rotating electrical machines are also of two types: DC and AC machines. Electrical machines are widely used.

How do rotating machines produce voltage?

In rotating machines, voltages are generated in windings or groups of coils by rotating these windings mechanically through a magnetic field, by mechanically rotating a magnetic field past the winding, or by designing the magnetic circuit so that the reluctance varies with rotation of the rotor.

How does a rotating machine work?

Rotating machinery or turbomachinery is a machine with a rotating component that transfers energy to a fluid or vice versa. Generally, if the energy transfer is from the rotor to the fluid, it is either a pump or fan. If the energy transfer is from the fluid to the rotor, then the machine is called turbine.

What is the rating for cylindrical type of winding with circular conductors?

What is the rating for cylindrical type of winding with circular conductors? Explanation: 5000-8000 kVA is used for rectangular conductors with cylindrical winding. 160-10000 kVA is used for helical winding. 200-10000 kVA is used for continuous disc type of winding.

What is the relation between clearances and slots?

What is the relation between clearances and slots? Explanation: When the skewed slots are being used, higher clearances are provided. High clearances can lead to the smooth and efficient operation of the machine for skewed slots.

What is a rotating equipment?

Rotating equipment is a term generally used in the oil and gas industries to describe the equipment and machinery that use kinetic energy to move fluids, gasses, and other materials. The rotating parts of the equipment can include turbines, pumps, generators, compressors, or engines.

What is cylindrical winding?

Cylindrical windings are low voltage windings used up to 6.6 kV for kVA up to 600-750, and current rating between 10 to 600 A. In multi-layered cylindrical windings, we use circular conductors, wound on vertical strips to improve cooling conditions. The arrangement creates oil ducts to facilitate better cooling.

Why do we use smooth cylindrical rotors in steam turbines?

The high-speed operation of rotor tends to increase mechanical losses, so the rotors should have smooth external surface. Hence smooth cylindrical type rotors with less diameter and large axial length are used for synchronous generators driven by steam turbines with either 2 or 4 poles.

What are the different types of rotating electric machines?

Rotating electric machines take many forms and are known by many names: dc, synchronous, permanent-magnet, induction, variable reluctance, hysteresis, brush- less, and so on.

What is the purpose of a rotating mechanical contact?

A rotating mechanical contact is used to supply current to the armature winding as the rotor rotates. 173 174 CHAPTER 4 Introduction to Rotating Machines Figure 4.1 Stator of a 190-MVA three-phase 12-kV 37-r/min hydroelectric generator.

How are rotor currents induced in induction machines?

In induction machines, rotor currents are induced in the rotor windings by a combination of the time-variation of the stator currents and the motion of the rotor relative to the stator.