What to pay attention to when choosing a brushless stepper motor

When choosing a stepper motor, the first thing to look at is its type. As mentioned earlier, this type of motor can also be divided into several types. Which one to choose? Each type has roughly the same function, but its There will be certain differences in the characteristics of the work and the scope of application. At this time, it is necessary to determine which motor to choose according to the requirements of the different work of the motor. That is to say, the first step of the selection is to determine the type. Secondly, when choosing a stepper motor, we also need to look at the quality. The quality of the motor is a fundamental issue, because no matter which type, good quality is the fundamental issue. If the quality is not good, the choice of the appropriate motor will be the same. Is not practical, this is a problem that needs attention.

　 One, select holding torque

　 Holding torque is also called static torque, which refers to the torque that the stator locks the rotor when the stepper motor is energized but not rotating. Since the torque of the stepper motor at low speed is close to the holding torque, and the torque of the stepper motor decays rapidly with the increase of speed, the output power also changes with the increase of speed, so the holding torque is a measure of stepping. One of the most important parameters of motor load capacity. For example,-generally speaking about 1N.m stepper motor without explanation, it can be understood that the holding torque is 1N.m.

    Second, choose the number of phases

The two-phase stepper motor has low cost, the step angle is at least 1.8 degrees, the vibration at low speed is large, and the torque drops quickly at high speed. It is suitable for high-speed occasions with low requirements for accuracy and stability; three-phase stepper motor step distance The angle is at least 1.2 degrees, the vibration is smaller than the two-phase stepper motor, and the low-speed performance is better than the two-phase stepper motor. The maximum speed is 30 to 50% higher than the two-phase stepper motor. It is suitable for high speed and requires accuracy and stability. Higher occasions; 5-phase stepping motor has a smaller step angle, and its low-speed performance is better than 3-phase stepping motor, but the cost is higher. It is suitable for occasions that require high accuracy and stability in medium and low speed sections.

    Three, choose stepper motor

The principle of selecting the motor first and then the stepping driver should be followed. First, the load characteristics should be clarified, and then by comparing the static torque and torque-frequency curves of different types of stepping motors, the stepping motor that best matches the load characteristics should be found; when the accuracy requirements are high, it should be Use a mechanical deceleration device to make the motor work in a state with the highest efficiency and the lowest noise; avoid making the motor work in the vibration zone, if necessary, change the voltage, current or increase the damping method to solve the problem; the power supply voltage

    Four, choose according to the use environment of the stepper motor

　 The special stepping motor is waterproof and oil-proof, and is used in some special occasions. For example, underwater robots need water-discharging motors. For special purpose motors, stepper motors must be selected specifically.

    Five, the selection of the no-load starting frequency of the stepper motor

　 No-load starting frequency of a stepper motor, usually called "idling frequency". This is an important indicator for purchasing a motor. If it is required to start and stop frequently in an instant, and the speed is about 1000 rpm (or higher), it is usually necessary to "accelerate the start". If you need to start directly to achieve high-speed operation, it is best to choose a reactive or permanent magnet motor. The "idling frequency" of these motors is relatively high.

　 The above are some issues to pay attention to when choosing a stepper motor. These are some factors to consider. Of course, in addition to these, the cost performance of a stepper motor is also a factor to be considered. These factors need to be considered comprehensively when choosing.