The best information about the usage of stpper motor
Here follow best information about the usage of stpper motor.
There are three basic types of step motors: variable reluctance, permanent magnet, and hybrid. This discussion will concentrate on the hybrid motor, since these step motors combine the best characteristics of the variable reluctance and permanent magnet motors. They are constructed with multi-toothed stator poles and a permanent magnet rotor(See figure A). Standard hybrid motors have 200 rotor teeth and rotate at 1.8º step angles. Because they exhibit high static and dynamic torque and run at very high step rates, hybrid step motors are used in a wide variety of commercial applications including computer disk drives, printers/plotters, and CD players. Some industrial and scientific applications of stepper motors include robotics, machine tools, pick and place machines, automated wire cutting and wire bonding machines, and even precise fluid control devices.
FULL STEP:
Standard hybrid stepping motors have 200 rotor teeth, or 200 full steps per revolution of the motor shaft. Dividing the 200 steps into the 360° of rotation equals a 1.8° full step angle. Normally, full step mode is achieved by energizing both windings while reversing the current alternately. Essentially one digital pulse from the driver is equivalent to one step.
HALF STEP:
Half step simply means that the step motor is rotating at 400 steps per revolution. In this mode, one winding is energized and then two windings are energized alternately, causing the rotor to rotate at half the distance, or 0.9°. Although it provides approximately 30% less torque, half-step mode produces a smoother motion than full-step mode.
MICROSTEP:
Microstepping is a relatively new stepper motor technology that controls the current in the motor winding to a degree that further subdivides the number of positions between poles. Omegamation microstepping drives are capable of dividing a full step (1.8°) into 256 microsteps, resulting in 51,200 steps per revolution (.007°/step). Microstepping is typically used in applications that require accurate positioning and smoother motion over a wide range of speeds. Like the half-step mode, microstepping provides approximately 30% less torque than full-step mode.
Speed and torque performance of the step motor is based on the flow of current from the driver to the motor winding. The factor that inhibits the flow, or limits the time it takes for the current to energize the winding, is known as inductance. The effects of inductance, most types of driver circuits are designed to supply a greater amount of voltage than the motor's rated voltage. The higher the output voltage from the driver, the higher the level of torque vs. speed. Generally, the driver output voltage (bus voltage) should be rated at 5 to 20 times higher than the motor voltage rating. In order to protect the motor from being damaged, the step motor drive should be current-limited to the step motor current rating.
The choice of a step motor depends on the application's torque and speed requirements. Use the motor's torque-speed curve (found in each drive's specifications, example in figure C) to select a motor that will do the job. Every stepper drive in the Omegamation line shows the torque-speed curves for that drive's recommended motors. If your torque and speed requirements can be met by multiple step motors, choose a drive based upon the needs of your motion system- step/direction, stand-alone programmable, analog inputs, microstepping- then choose one of the recommended motors for that drive. The recommended motor list is based on extensive testing by the manufacturer to ensure optimal performance of the step motor and drive combination.
Types of stepper motors.
stages and indicators:
These step motor drives accept step pulses and direction/enable signals from a controller, such as a PLC or PC. Each step pulse causes the motor to rotate a precise angle, with the frequency of the pulses determining the speed of rotation. The direction signal determines the direction of rotation (CW or CCW), while the enable signal turns the motor on or off.
Oscillator:
Step motor drives with a built-in digital oscillator accept an analog input or joystick for speed control. These systems are generally used in applications requiring continuous motion rather than position control, such as mixers, blenders, and dispensers.
High preference:
These step motor drives offer advanced features such as self-test diagnostics, fault protection, auto-tuning, torque ripple smoothing, command signal smoothing, and anti-resonance algorithms. Some drives are stand-alone programmable, while others offer step/direction and analog inputs. High-performance drives will provide the best possible performance for your motion control system.
Monday, 9 March 2015 - 
stepper motor tips
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