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A few words about the stepper motor-converted

A stepper motor is an electromechanical device that converts electrical impulses into discrete mechanical movements. The shaft or spindle of a stepper motor rotates in discrete increments of steps when electrical control pulses are applied to it in the correct order.

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A few words about the stepper motor-converted

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  1. A few words about the stepper motor (advantages, disadvantages and classification) Introduction A stepper motor is an electromechanical device that converts electrical impulses into discrete mechanical movements. The shaft or spindle of a stepper motor rotates

  2. in discrete increments of steps when electrical control pulses are applied to it in the correct order. The rotation of motors has several direct relationships with these applied input pulses. The sequence of pulses applied is directly linked to the direction of rotation of the motor shafts. The speed of rotation of themotor shafts is directly related to the frequency of the input pulses and the duration of rotation is directly related to the number of input pulses applied. Advantages and disadvantages of stepper motor Benefits 1. The angle of rotation of the motor is proportional to the input pulse. 2. Motor has full torque at standstill ( if windings are on ) 3. Accurate positioning and repeatability of movement since good stepper motors have an accuracy of 3 to 5% from one step and this error is not cumulative from one step to another. 4. Excellent response to start / stop / reverse. 5. Very reliable because there are no contact brushes in the motor. Therefore, the life of the motor simply depends on the life of the bearing. 6. The motor's response to the digital input pulses enables open-loop control, making the motor simpler and less expensive to control.

  3. 7. It is possible to achieve synchronous rotation at very low speed with a load directly coupled to the shaft. 8. A wide range of rotational speeds can be achieved because the speed is proportional to the frequency of the input pulses. Disadvantages 1. Resonances can occur if not properly controlled. 2. Not easy to use at extremely high speeds. Open loop operation One of the most important advantages of a stepper motor is its ability to be precisely controlled in an open loop system. Open loop control means no position feedback information is required. This type of control eliminates the need for expensive sensing and feedback devices such as optical encoders. Your position is known simply by keeping track of the input step pulses. Types of stepper motors There are three basic types of stepper motors. They are:

  4. 1. Variable reluctance (VR) 2. Permanent magnet (PM) 3. Hybrid (HB) Variable reluctance (VR) This type of stepper motor has been around for a long time. This is probably the easiest to understand from a structural point of view. Figure 1 shows a cross section of a typical RV. step-by-step engine. This type of motor consists of a soft iron multi-tooth rotor and a wound stator. When the stator windings are supplied with direct current, the poles become magnetized. The rotation occurs when the teeth of the rotor are attracted to the poles of the stator under tension. Permanent Magnet (PM) Often referred to as a “can” or “can store” motor, the permanent magnet stepper motor is a low cost, low resolution type motor with typical step angles of 7.5 ° to 15 °.

  5. (48 - 24 steps / revolution) PM Motors As the name suggests, permanent magnets are added to the motor structure. The rotor no longer has teeth as with the VR motor. Instead, the rotor is magnetized with alternating north and south poles located in a straight line parallel to the rotor shaft. These magnetized rotor poles provide increased magnetic flux intensity and hence the PM motor has better torque characteristics compared to type VR. Hybrid (HB) The hybrid stepper motor is more expensive than the PM stepper motor, but offers better performance in terms of step resolution, torque and speed. Typical step angles for the HB stepper motor range from 3.6 ° to 0.9 ° (100 - 400 steps per revolution). Hybrid stepper motor combines the best features of PM and VR type stepper motors. The rotor is multi-toothed like the VR motor and contains an axially magnetized concentric magnet around its shaft. The teeth on the rotor provide an even better path which helps guide the magnetic flux to preferred locations in the air gap. This further

  6. increases the engine's rebound, hold and dynamic torque characteristics compared to VR and PM types. The two most commonly used types of stepper motors are permanent magnet and hybrid types. Make the right choice If a designer is unsure which type will be best suited to meet the demands of their applications, they must first assess the type of PM as it is normally several times cheaper. Otherwise, the hybrid engine may be the right choice. Special models of stepper motors are also offered. One is the disk's magnetic motor. Here the rotor is designed as a disc with rare earth magnets This type of motor has certain advantages, such as very low inertia and an optimized magnetic flow path without coupling between the two stator windings.

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