In this paper, the designs of the various drives of the stepper motor are presented. The main objective of this paper is to analyze the various drives of the stepper motor. Basically the Design consist four sections. First part is power supply. We required two supply 5v and 12v. Second part is clock circuit which generates the clock pulses for sequential logic circuit. Third part is sequential circuit which generates the four logic sequences for driver circuits. And the final and most important part is driver circuits, Which consists of a total of four drives. Basically the project hardware consist of four sections. First part is power supply. We required two supplies 5v and 12v. Second part is the clock circuit which generates the clock pulses for sequential logic circuit. And the final and most important part is the driver circuits, Which consists of a total of seven drives.
Keywords: Diode Suppression, Diode-Resistance Suppression, Zener-Diode Suppression, Capacitor Suppression, Recovery on High Voltage, Series-Resistance Driver.
[...] Some variations of the series-resistance drive scheme are: The number of resistors may be reduced by placing only one resistor in the common return lead of the motor or in the power supply lead. Fig 2.7 b shows the output waveforms of the voltage and current of the series-resistance driver circuit without load and fig 2.7 c shows the output waveforms of the voltage and current of the series-resistance driver circuit with load. Fig 2.7 a Series-Resistance Driver Circuit Fig 2.7 b The output waveforms of Series-Resistance Driver Circuit without load currents when the motor is at detent position. [...]
[...] In addition, as the motor rotates it generates a back emf, Eb, which acts against the supply voltage An equivalent circuit of the winding of one phase of the step motor is shown in fig 2.1 Typically, the winding resistance tolerance is plus or minus 10%. Since most step motors are designed to operate quite hot, in the order of 100 degree centigrade case temperature, as the motor heats up during operation, the winding resistance increases. It is not unusual for the winding resistance to vary up to 25% during normal operation. [...]
[...] APPLICATIONS Stepper motors are used in a wide variety of applications in industry, including computer peripherals, business Machine Tools machines, motion control, and robotics, which are included in process control and machine tool applications. A complete list of applications is shown below. Computer Peripherals FUTURE SCOPE There is enough scope of further development in driver circuit, by using the pulse width or freq modulation to control the average current to the step motor windings. In that the current sensing network is used to turn off the switching transistor when the current reaches the rated value and when the current decreases below some preset threshold value the switching transistor is turned on again. [...]
[...] This is most common and the least expensive scheme to improve the performance of step motor is to add series resistors to each phase winding of the step motor. The disadvantage with the series-resistance drive is the additional power being dissipated in the external resistor, thus causing the system to be inefficient. Seventh and last drive is RC drive. The disadvantage of the RL drive is removed by this drive. The series resistors may be shunted with capacitors. This provides a low impedance path around the resistors during transient conditions. [...]
[...] Fig 2.2 a Diode Suppression Circuit Fig b Output wave form of Diode suppression circuit without load Fig c Output wave form of Diode suppression circuit with load DIODE-RESISTANCE SUPPRESSION When high slew speed is desired, the energy in the winding of the off-phase must be dissipated as quickly as possible. This can be accomplished by adding a resistance Rs in series with the free-wheeling diode to reduce the time constant of the discharge circuit, as shown in Fig 2.3 a. [...]
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