Machines of the direct current: general information
The machine of the direct current — the electrical machine with the mekhaniyochesky switch — the collector allowing осуществлять continuous electromechanical transformation of energy by transformation of the direct current in variable (the mode dvigayotelny) or alternating current in constant (the mode generatoryony).
Switching — process of switching of electric circuits. In machines of the direct current this process is carried out by the pereyoklyuchatel — the collector. Thus, machines of the direct current apply in the kayochestvo of engines and as generators.
The machine of the direct current consists of the motionless chasyota serving for creation of the main magnetic field, and вращающейся parts — anchors in which the elektroyodvizhushchy force (EMF) is induced. Currents from EMF, interacting with the main magnetic field, create the brake moment in the generating reyozhim and the torque in motive.
Motionless part consists of the bed on which the main (main) poles for creation of the main magnetic field become stronger.
Anchor — the part of the machine in which winding, at rotation of its rather main magnetic field, EMF is induced. In the mayoshena of the direct current the anchor consists of the toothed core, the obyomotka laid in its grooves and the collector got on the anchor shaft. The armature core is gathered from the sheets of electrotechnical steel 0,5 mm thick isolated from each other is delicious. In grooves of the armature core the anchor winding consisting of separate sections is laid. For withdrawal of current from the collector the brushes installed in brush holders serve.
One of the main parts of electrical machines of the constant toyok — the collector — the hollow cylinder assembled from the wedge-shaped copper plates isolated from each other which are separated also from the machine shaft. Conductors they unite to rounds of the winding placed in anchor grooves. The rotating obyomotka connects to the external circuit the sliding contact between brushes and the collector.
The most important classification sign of machines of the direct current — the way of excitation of the main magnetic field. The magnetizing coil placed on cores of poles of the machine is for this purpose used. All performance characteristics of machines of the direct current during the work both in the generator mode, and in the mode of the engine depend on the way of inclusion of the exciting circuit in relation to the anchor chain. Connection of these chains can be parallel, poyosledovatelny, mixed, and, at last, these chains can be neyozavisima one from another according to what it is accepted to distinguish the parallel, consecutive, mixed and independent vozbuzhyodeniye of machines.
Machines of the direct current, except for large machines of extreme power (mainly the engines and generators used in the system of the drive of rolling mills, bloomings and slabbings), produce in our country in lots. Principal series of machines of common industrial application — the uniform series P which okhyovatyvat all necessary power range and frequencies the vrashcheyoniya. Except it release some other specialized series: traction, crane and metallurgical, ship, for the drive of vspoyomogatelny systems of cars, tractors and airplanes, for the systems of automatic control, etc.
The uniform series P includes electrical machines of 2 types: common industrial application (fig. 1) and specialized assignment.
Electric motors of common industrial application allow rotating speed regulation no more than concerning 1:2. The execution protected — machines are protected from accidental touch to the rotating and current carrying parts and also from hit in foreign objects.
Electric motors of specialized assignment have zayokryty execution which excludes direct soobshcheyony between their internal space and the environment. They differ in the variety of mechanical characteristics, shiyoroky limits of regulation of rotating speed.
Generators of common industrial application have the parallelyyony or mixed self-excitation. Are applied to the power supply of control circuits, electric motors and machines of the direct current.
Generators of specialized assignment are intended for charging of rechargeable batteries, the power supply of powerful spetsialiyozirovanny direct current motors, etc. Depending on the power of the machine of the uniform series P are divided into 3 groups: I \0,3-200 0,3-200 kW; II \200-1400 kW; III \over 1400 kW.Top