Stepper Motor Applications
Stepper motor in electronic clocks and watches
The quartz clock is mainly composed of quartz resonator, integrated circuit, stepper motor (for pointer type), LCD display (for digital watch), battery or AC power supply. In addition, it also includes a conductive rubber, trimmer, lighting lamp, buzzer and other components. In the pointer quartz watch, in order to indicate the time by turning the electric signal into the pointer, the micro stepper motor and the gear drive system are adopted as the gear drive system. In the pointer type quartz clock, the stepper motor is used as transducer to turn the second pulse signal into the rotation of the mechanical gear, which drives the indicator to indicate the time. Stepper motor is characterized by low power consumption, small volume, high conversion efficiency and simple structure.
The common clock stepper motors have double eccentric type, single eccentric type, double-concave type and single pit type radial magnetized permanent magnet stepper motor, and double stator axial magnetization stepper motor. Among them, the double-concave type stators are integrated into a whole, with the advantages of simple structure, low power consumption, wide application. Compared with quartz watches, quartz clock stepper motor has larger volume, more power consumption and larger output torque. Rotor magnet steel of the stepper motor adopts the alloy materials with large coercive force and large remanence density, such as samarium cobalt alloy, permeability alloy frequently-used in stator. The coil often uses the varnished wire of small diameter and high strength.
Stepper motor in industrial robot
Industrial robot indicates an electronics automation device integrating imitating man’s hand action, substituting human hand to grasp and carry workpiece or operating tools according to the set program, track and requirement. It also indicates an actuating element used to transform the pulse signal into linear displacement. The output displacement of the stepper motor is in direct proportion to the input pulse number while its velocity is also in direct proportional to pulse number input within the unit time (namely the pulse frequency) and its rotational direction is relevant to the phase sequence of pulse distributed to each phase winding of the stepper motor. Therefore, so long as the number and frequency of command pulse and power-on phase sequence of motor winding can be controlled, the output displacement amount, velocity and direction and stepper motor can be controlled. The stepper motor features good control performance. Its start, stopping, inversion and change in any operation mode can be finished within less pulses. Besides, high control precision can be obtained. Thus, it is widely applied. PLC is used to generate control pulse. Certain quantity of square-wave pulses are output through PLC programming to control the corner of the stepper motor and then further control the feed rate of the servo mechanism. In the meantime, the feed velocity of the servo mechanism is controlled by controlling the pulse frequency through programming. The method for controlling 3-phase stepper motor with PLC is easy and reliable.
Stepper motor in packaging machinery
The control gear pump of the stepper motor can also achieve accurate measurement. The gear pump is widely used in conveying viscous body, such as the conveying of the syrup, wine, oil, bean paste, tomato sauce. Gear pump metering is measured by a pair of gear meshing rotation, and the material is forced to be sent from the feed inlet to the outlet port between the spaces of the gear. The power comes from the stepper motor and the position and speed of the stepper motor are controlled by programmable controller. The measurement accuracy is higher than the accuracy of the piston pump. The stepper motor is suitable for running at low speed. When the speed is accelerating, the noise of the stepper motor will be increased obviously and other economic indexes will decrease significantly. For the gear pump with high rotational speed, it is better to choose the lifting speed structure. The structure of step motor direct gear pump is used in the thick body packaging machine. The result is that the noise cannot be avoided and the reliability is decreased. Then the straight gear raising speed is adopted, the speed of the stepper motor is reduced, the noise is controlled, the reliability is improved and the degree of measurement is guaranteed. In the packaging machine of bag making, filling and sealing, the plastic film positioning and fixed length supply is required, and the stepper motor can be reliably completed regardless of intermittent supply or continuous supply. The stepper motor and the drawstring contact roller are directly connected. Its structure is smplified and the regulation is very convenient. It can be achieved through the button on the control panel, which not only saves the adjusting time but also saves the packaging materials.