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The benefits of DC electrical control speed in relatively simple terms, only the control voltage can control the total size has speed, but not in the heat of such motors, and other environmental flammable operate, and because The need to brush as the motor current converter (Commutator) components (with brush motors), so they need regular cleaning of carbon brushes dirt produced by friction. The brushless motor as Brushless motors, compared with the brush, brushless motor, carbon brush and shaft for less friction and therefore less power is relatively quiet. Production more difficult, the price is high.
AC motors can at high temperature, flammable and other operating environments, and do not regularly clean up the brush dirt, but speed control is relatively difficult to control AC motor speed as required to control the frequency of alternating current (or the use of induction motors, with an increase internal resistance of the way, in the same lower frequency AC motor speed), control the voltage will only affect the motor torque. General civil motor voltage 110V and 220V so two, in industrial applications such as patterns are 380V or 440V.
Synchronous motor in structure, there are two:
1.Carried out with DC rotor excitation
It was made very type rotor installed in the magnetic core magnetic coil above each other in series, then as having alternating opposite polarity, and has two leads connected to the shaft of the two mounted above the slip ring . Magnetic coil is a small DC generator or battery to stimulate, in the majority of synchronous motor, DC generator is mounted on motor shaft, to supply the rotor pole coil excitation current. Because of this synchronous motor does not automatically start, so also is equipped with squirrel-cage rotor winding and used as a motor launch. On the rotor squirrel cage winding around the structure and Asynchronous similar. When the stator windings through the three-phase AC power, the motor generated within a rotating magnetic field, squirrel cage winding cutting induced current generated magnetic field lines, so that motor to spin. After the motor rotation, its speed gradually increased to slightly less than the speed of rotating magnetic field, this time by the DC to the rotor field coil excitation, the rotor pole above a certain form, they attempt to track the stator poles on the rotating pole, thus increasing motor rotor speed up to synchronous rotation with the rotating magnetic field up.
2.Without excitation of the synchronous motor rotor
Excitation of the synchronous motor rotor can not be applied single-phase power supply can also be used in multi-phase power supply. This motor, there is a split-phase stator winding and stator motor or similar multi-phase motor, while a squirrel cage rotor, and rotor cut into the surface plane. So this is obviously very rotor, the rotor magnetic pole is made from a magnetic steel, and can keep the magnetism. Squirrel cage winding is used to produce starting torque, but when the motor rotation to a certain speed, the rotor was very on the catch frequency of the stator coil current to achieve synchronization. The polarity was extremely sensitive by the stator out, so it should be and the number of stator poles are equal, when the motor due to its speed, squirrel cage winding lost role in maintaining the rotation is by the rotor and catch the stator magnetic pole, so that synchronization.
Dc voltage dc is depend on the motor running, widely used in radio, video, VCD, electric razor, hair dryer, electronic, toys, etc.
Assolenoid style dc motor stator poles by assolenoid style, rotor (armature), the commutator (known as ZhengLiuZi), brush, chassis, bearing structure, the motor stator assolenoid style (main) by the magnetic poles and field winding. Core According to its excitation (old standard called excitation) can be divided into different ways of dc series-excited motor excitation and shunt motor, his motivation and compound excitation motor. Because of different ways of excitation, stator magnetic flux (stator winding of excitation of polarity of the different laws). Series-excited motor excitation winding and rotor winding through the brush and between commutator in series, exciter current and armature current is proportional to the stator flux, with the current increases torque approximation and armature current is proportional to the rotation, with torque or current increases rapidly. Its starting torque can reach the rated torque of more than 5 times, the short time overload torque of 4 times of rated torque and speed than bigger change in high speed, load (usually not allowed under no-load running in). Through using external resistors series-excited winding series (or parallel), or will series-excited winding up to realize stepless change in parallel. And the field winding motor excitation in parallel with the rotor winding, the current is constant, starting torque and armature current is proportional to the starting current, about 2.5 times of rated current. Speed and torque with current increase and declined slightly, short-term overload torque is 1.5 times of rated torque. Speed rate of 5% ~ 15%, smaller. Through the field can be weakened constant power to control. He shunt motor excitation winding received independent power supply, the excitation constant current also relatively, starting torque and is proportional to the armature current. Speed change also 5% ~ 15%. Can pass away weak magnetic field to improve the speed of constant power or by reducing rotor winding speed reduced to the voltage. Compound excitation motor stator pole on a shunt winding, and with the series with the rotor winding series-excited winding (the ratios less). Series winding magnetic flux generated with the direction of the winding magnetic flux in the same direction, starting torque is about 4 times of rated torque, short time overload torque is 3.5 times rated torque. Speed rate for 25% ~ 30% (about) with tandem winding. Speed can be weakened by magnetic field to adjust. The commutator piece using silver under copper and cadmium copper alloys with high intensity, plastic moulded into. Brush with the commutator sliding contact for rotor winding, provide armature current. Dc assolenoid style of general use brush brush or metal graphite audio-visual graphite brush. The rotor core using silicon steel, generally for an embedded trough, December 12, between armature winding up again after a series, with 12 slices reversing chips.
And other rotor windings without power, the stator current directly from ac power system, Compared with other motor of asynchronous motor, simple structure, manufacture, use and maintenance convenience, high reliability, light weight, low cost. In three-phase Induction motor, for example, with power and speed of dc motors, compared to only the latter half of the weight of cost, only for a third. Induction motor is easily according to the different requirements of environmental conditions, derives all kinds of products. It also has the nearly constant speed, can satisfy the load characteristics of agricultural production in most of the mechanical drive. Its limitations, it is the speed of a rotating magnetic field with synchronous speed of a fixed slip (see induction motor speed), and therefore, in a broad smooth requirements of speed range using occasions (such as transmission, hoist, large machine etc), economic, convenient as dc. In addition, asynchronous motor running from power system, from reactive power, leading to excitation in power system of power factor. Therefore, in the high and low speed situation (e.g., dragging the ball mill, the compressor etc) use synchronous motor is reasonable
Controller: the operation instructions, the controller must transmit demand and operation of the pulse signal instructions. To use the Hybrid Stepper Motor controller or programmable controller for the positioning module. The operation command transmitted pulse signal as the beating of the heart of the rectangle waveform is presented, and the intermittent signal.
Driver: to provide power to ensure operation according to the instructions, drive motor with controller to transmit power to control the pulse signal, the current flow sequence by decision of excitation circuitry, and control to provide power to drive motor circuit
Motor ontology into motive power: on command, and number of pulse demand.
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