Pushbutton switch refers to the use of the button to promote the transmission mechanism, so that the dynamic contacts and static contacts press through or disconnect and realize the circuit switch. Pushbutton switch is a simple structure, the application of a very wide range of main electrical appliances. In the electrical automatic control circuit, used to manually send a control signal to control the contactor, relay, electromagnetic starter.
Single-phase motors generally refer to low-power single-phase asynchronous motors powered by a single-phase AC supply. These motors usually have two-phase windings on the stator and an ordinary squirrel-cage rotor. The distribution of the two-phase windings on the stator and the difference in power supply can produce different starting and operating characteristics.
The method of connecting the pictures is shown in the diagram:
Extended information:
A single-phase motor is an asynchronous motor that operates on 220V AC single-phase power. Because 220V power supply is very convenient and economical, and family life with electricity are 220V, so single-phase motor not only in the production of a large amount, but also with people's daily life, closely related, especially with the people's living standards are increasingly improving, household electrical equipment, single-phase motor usage, but also more and more.
Applied in the production of micro-pumps, grinders, threshing machines, pulverizers, woodworking machinery, medical equipment, etc., in terms of life, there are fans, hair dryers, exhaust fans, washing machines, refrigerators, etc., a wider variety of types, but the power is smaller.
When a single-phase sinusoidal current passes through the stator winding, the motor will produce an alternating magnetic field, the strength and direction of this magnetic field at any time for the sinusoidal law changes, but in the spatial orientation is fixed, so it is also known as the magnetic field is alternating pulsating magnetic field.
This alternating pulsating magnetic field can be decomposed into two to the same speed, the direction of rotation is the opposite of the rotating magnetic field, when the rotor is stationary, the two rotating magnetic field in the rotor to produce two equal size, the direction of the opposite torque, so that the synthetic torque is zero, so the motor can not rotate.
When we use an external force to make the motor rotate in a certain direction, then the rotor and clockwise rotation direction of the rotating magnetic field between the cutting line of magnetic force movement becomes smaller; rotor and counterclockwise rotation direction of the rotating magnetic field between the cutting line of magnetic force movement becomes larger. Thus the equilibrium is broken, and the total electromagnetic torque produced by the rotor will no longer be zero, and the rotor will rotate in the direction of propulsion.
To make a single-phase motor can automatically rotate up, we can add a starting winding in the stator, the starting winding and the main winding in the space difference of 90 degrees, the starting winding should be connected in series with a suitable capacitor, so that the current with the main winding in the phase of the approximate difference of 90 degrees.
The so-called split-phase principle. Thus two currents 90 degrees apart in time flowing into two windings 90 degrees apart in space will produce a (two-phase) rotating magnetic field in space.
Under the action of this rotating magnetic field, the rotor can automatically start, after starting, when the speed rises to a certain point, with the help of a centrifugal switch installed on the rotor or other automatic control devices will start the winding disconnect, normal operation only the main winding work.
Therefore, the starting winding can be made to work for a short time. But there are many times, the starting winding does not disconnect, we call this motor for single-phase motor, to change the steering of this motor, as long as the auxiliary winding terminals can be switched.
In single-phase motors, another method of generating a rotating magnetic field is called shaded-pole method, also known as single-phase shaded-pole motor. The stator of this type of motor is made into a convex pole type, there are two poles and four poles.
Each pole in 1/3 to 1/4 of the whole pole surface with a small groove, the pole is divided into two parts, in the small part on the set of a short-circuiting copper ring, as if this part of the magnetic pole cover up, so it is called shaded-pole motor. The single-phase windings are set over the entire magnetic pole, and the coils of each pole are connected in series, and must be connected so that the poles they produce are arranged in sequence according to N,S,N,S.
When the stator winding is energized, a main magnetic flux is generated in the poles, according to the corrugated law, in which the main flux through the short-circuited copper ring produces an induced current in the copper ring lagging 90 degrees in phase, and the flux generated by this current also lags behind the main flux in phase, which is comparable to the capacitor motor's starter winding, thus generating a rotating magnetic field to turn the motor.?
Baidu Encyclopedia - Single-phase motor