The brush is made of precious metal alloy and is "II" shaped with symmetrical double contact with the groove of the conductive ring. The elastic pressure of the brush is in sliding contact with the groove of the conductive ring to transmit signals and current. .
Collection rings are also called conductor rings, slip rings, collector rings, bus rings, etc. It can be used in any electromechanical system requiring continuous rotation while transmitting power and signals from a fixed position to a rotating position. Slip rings can improve system performance, simplify the system structure, and prevent wires from being strained during rotation.
Slip ring synchronous motors and asynchronous motors using slip rings are widely used in industrial sectors and most of them operate in dvarious difficult conditions. Although these motors do not have the commutating function of DC motors, like commutators, they also suffer from abnormal wear of commutator rings or brushes, brush vibration, and spark generation. Especially from the perspective of brush material, not only graphite brushes are used for slip ring brushes, but also metal graphite brushes are sometimes used to increase the current density of the brush. Therefore, factors such as abnormal residual expansion must also be considered. Even for high-speed engines such as turbogenerators or engines operating in fully enclosed gas and hydrogen media, many problems arise.
The collector ring material requires high mechanical strength, good electrical conductor and corrosion resistance. Duringthat it is in sliding contact with the brush, it must have stable wear resistance and sliding contact characteristics. Generally, steel slip rings have good wear resistance and high mechanical strength, so they are mainly used in synchronous motors where the slip ring wear difference is large due to polarity.
The factors that cause fires in the collector ring of the generator are:
1. The quality of carbon brushes is poor. Carbon brushes break easily if overheated. causes the carbon brushes to come into contact with the collector. An arc between the collector rings;
2. Hydrogen leaking from the generator sealing tile near the collector ring;
3. The collector ring cooling air inlet is blocked, causing drafts. The quantity is reduced, which affects the cooling effectidization of the collector ring surface;
4. The generator seal oil is leaking and the carbon powder is not discharged. smoothly, and the mixture of oil, gas and carbon powder contaminates the collector ring chamber;
< p>5. Poor contact between the carbon brush and the commutator ring surface, overheating of the commutator ring surface and carbon brush assembly, etc. Among them, poor contact between the carbon brush and the slip ring is the main reason for the fire accident of the slip ring. Poor contact between the carbon brushes and the commutator ring causes local sparking, causing an increase in the temperature of the commutator ring, deterioration of carbon brush contact, and uneven distribution of excitation current between the brushes coal, resulting in a ring fire. Poor contact between the carbon brush and the surface of the collecting ringur is generally difficult to detect, causing collector ring fires that last relatively short time and are therefore difficult to treat in time.The stator is the fixed part of the motor or generator. The stator consists of three parts: the stator core, the stator winding, and the frame. The main function of the stator is to generate a rotating magnetic field, while the main function of the rotor is to be cut by magnetic lines in the rotating magnetic field to generate (output) a current.
Rotor refers to the rotating body supported by bearings. An object such as an optical disk that does not have its own axis of rotation may be considered a rotor when it adopts a rigid connection or additional axis. The motor rotor is usually composed of a wound iron core with coils, slip rings, fan blades, etc. Main components that turnoperate at high speed in electrical machines or work machines such as electric motors, generators, gas turbines and turbine compressors.
Detailed information:
1. Components and principles of generator:
< p>The generator is mainly composed of stator, rotor, end cover, brush, frame, bearing and other components. The stator consists of a machine base, a stator core, wire windings and other structural parts that secure these parts. The rotor consists of the rotor core, rotor magnetic poles (with magnetic yoke and magnetic pole windings), slip rings (also called copper rings, slip rings), fans and rotating shafts.The generator stator and rotor are connected and assembled through the bearing, base and outer coverremited, so that the rotor can rotate in the stator. Some excitation current passes through the slip ring, so that. the rotor becomes a rotating magnetic field. The stator coil moves to cut the magnetic lines of force, thereby generating an induced electrical potential, which is drawn across the terminals and connected in the circuit to generate current.
Due to a broken connection between the brush and the rotor, the rotor rotates in a certain direction and generates alternating current. Therefore, there is alternating current in household and other circuits, called. alternating current. The output current frequency of the Chinese power grid is 50 Hz.
2. Classification of rotors:
Typical rotors include turbine machine rotors, engine rotors, various pump rotors and turbine compressor rotors, etc. When the rotor turns at certain vspecific speeds, it undergoes a large deformation and causes a resonance. The speed at which it causes resonance is called the critical speed of the rotor.
In engineering, a rotor whose operating speed is less than the first-order critical speed is called a rigid rotor, and a rotor whose operating speed is greater than the first-order critical speed is called flexible rotor. .
As the rotor rotates at high speed, it must be balanced. Static balancing is mainly used to balance the inertia force of the rotor disk. Dynamic balancing of rigid rotors can use a universal balancing machine to balance the inertia force and inertia torque to eliminate the vibration of the rotor on the elastic support.
The dynamic balance of flexible rotors is relatively complex. It can be distinguished in principle into two types: the vibratio shape balance methodn and the influence coefficient method.
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