28 Differences between Servo Motor and Stepper Motor

1, how to choose the right servo motor and stepper motor? Mainly depending on the specific application conditions, simply to determine: the nature of the load (such as horizontal or vertical load, etc.), torque, inertia, speed, accuracy, acceleration and deceleration and other requirements of the host control requirements (such as port interface and communications The requirements), the main control method is position, torque or speed mode. Power supply is DC or AC power, or battery-powered, voltage range. Based on this to determine the motor and drive or controller model. 2, choose stepper motor or servo motor system? In fact, the choice of what kind of motor should be based on the specific application circumstances, each with its own characteristics. 3, how to use stepper motor driver? According to the motor current, with more than or equal to the current drive. If you need low vibration or high precision, can be equipped with subdivision type drive. For large torque motors, use high-voltage type drivers wherever possible to achieve good high-speed performance. 4, 2 phase and 5 phase stepper motor What is the difference, how to choose? The 2-phase motor has a low cost but has a large vibration at low speed and a fast torque drop at high speed. 5-phase motor is less vibration, high-speed performance, higher than the 2-phase motor speed 30 to 50%, in some cases to replace the servo motor. 5, when to use DC servo system, AC servo and what is the difference? DC servo motor is divided into brush and brushless motor. Brush motor low cost, simple structure, large starting torque, wide speed range, easy to control, need maintenance, but easy maintenance (for carbon brush), resulting in electromagnetic interference, the environment has requirements. So it can be used for cost-sensitive general industrial and commercial applications. Brushless motor small size, light weight, large output, fast response, high speed, small inertia, smooth rotation, torque stability. Control complex, easy to achieve intelligent, the electronic commutation method is flexible, square wave commutation or sine wave commutation. Motor maintenance-free, high efficiency, low operating temperature, electromagnetic radiation is small, long life, can be used in a variety of environments. AC servo motor is also a brushless motor, is divided into synchronous and asynchronous motor, the current motion control are generally used synchronous motor, its power range, you can do a lot of power. Large inertia, high maximum speed of rotation, and quickly decreases as power increases. It is suitable for low-speed smooth operation of the application. 6, when using the motor to pay attention to the problem? Before power-on, make the following checks: 1) Whether the power supply voltage is suitable (overvoltage may cause damage to the drive module); +/- polarity of the DC input must not be wrong, and the motor model or current on the drive controller 2) The control signal line is firmly connected to the industrial site, it is best to consider the shielding problem (such as the use of twisted pair); 3) Do not start the need to take the line all the way On, even into the most basic system, running well, and then gradually connected. 4) Be sure to figure out the grounding method, or use the floating does not answer. 5) Start working within half an hour to closely observe the state of the motor, such as exercise is normal, the sound and temperature conditions, found that the problem immediately shut down to adjust. 7, stepper motor start running, and sometimes do not move or move back and forth from time to time, running sometimes out of step, what is the problem? Generally consider the following aspects for inspection: 1) Whether the motor torque is large enough to drive the load, we generally recommend the user to choose the motor torque 50% ~ 100% larger than the actual needs, because the stepper motor can not be over Load operation, even if it is an instant, will result in out of step, serious stop or irregular repeatedly move. 2) If the current of the walking pulse input by the host controller is large enough (usually> 10mA) to make the optocoupler stable and conductive, the input frequency is too high, which can not be received. If the output signal from the host controller Is a CMOS circuit, you have to use CMOS input type of drive. 3) If the starting frequency is too high, whether the acceleration process is set in the startup program, it is best to start accelerating to the set frequency within the starting frequency specified by the motor, even if the acceleration time is very short, or it may not be stable or even in an inert state . 4) When the motor is not fixed well, this condition sometimes appears, it is normal. Because in fact at this time caused a strong resonance of the motor into the out of step. Motor must be fixed. 5) For the 5-phase motor, the phase error, the motor can not work. 8, I want to directly control the servo motor through communication, can I? Yes, more convenient, but speed, for applications that require less responsiveness. If you need to respond quickly to control parameters, it is best to use servo motion control card, it is generally above the DSP and high-speed logic processing circuit to achieve high-speed high-precision motion control. Such as S acceleration, multi-axis interpolation. 9, with the switching power supply to stepping and DC motor system is good? Generally best not to, especially large torque motor, unless more than twice the power required more than switching power supply. Because, when the motor is a large inductive load, the power supply will form an instant high voltage. The switching power supply overload performance is not good, it will protect the shutdown, and its precision voltage regulator performance is not needed, and sometimes may result in switching power supply and drive damage. Can use conventional ring or R-type transformer DC power supply. 10, I want to use ± 10V or 4 ~ 20mA DC voltage to control the stepper motor, can it? Yes, but you need another conversion module. 11, I have a servo motor with encoder feedback, can only use the servo drive with speed control port control? Yes, you need an encoder speedometer signal module. 12, servo motor encoder part can be opened apart? Do not disassemble, because the quartz plate inside the code plate is very easy to rupture, and after entering the dust, the life and precision will not be guaranteed, which requires the professionals' overhaul. 13, stepping and servo motor can be disassembled or modified? Do not, it is best to let the manufacturers to do, after disassembling no professional equipment is difficult to install back to the original, the motor can not guarantee the clearance between the stator. Magnet material properties are destroyed, and even cause loss of magnetism, motor torque decreased significantly. 14, the servo controller can sense changes in external load it? In the event of resistance set stop, return or maintain a certain thrust follow-up. 15, can be domestic drive or motor and foreign high-quality motor or drive with it? In principle, it is possible, but to figure out the technical parameters of the motor before it can be used, otherwise it will greatly reduce the desired effect, or even affect long-term operation and life expectancy. The best advice to the supplier before deciding. Is it safe to drive the motor with a DC supply voltage greater than the rated voltage? Normally this is not a problem as long as the motor is operating within the set speed and current limits. Because the speed of the motor is proportional to the line voltage of the motor, selecting a supply voltage does not cause over-speed, but failure of the drive may occur. In addition, it must be ensured that the motor meets the minimum inductance of the drive and that the set current limit is less than or equal to the rated current of the motor. In fact, this is good if you can run the motor slowly (below the rated voltage) in the device you designed. Running at a lower voltage (and therefore at a lower speed) results in less brush runback and less brush / commutator wear, lower current draw, and longer motor life. On the other hand, if the motor size and performance requirements require extra torque and speed, over-driving the motor is also acceptable, but at the expense of the product's service life. 17, how to choose the right power supply for my application? It is recommended to select the power supply voltage higher than the maximum required voltage by 10% -50%. This percentage varies with Kt, Ke, and the voltage drop across the system. The current value of the driver should be sufficient to deliver the energy required by the application. Remember that the output voltage of the driver is different from the supply voltage, so the driver output current is also different from the input current. To determine the proper supply current, all of the power requirements for this application need to be calculated, increasing by 5%. Press I = P / V formula to calculate the required current value. It is recommended to select the power supply voltage higher than the maximum required voltage by 10% -50%. This percentage varies with Kt, Ke, and the voltage drop across the system. The current value of the driver should be sufficient to deliver the energy required by the application. Remember that the output voltage of the driver is different from the supply voltage, so the driver output current is also different from the input current. To determine the proper supply current, all of the power requirements for this application need to be calculated, increasing by 5%. Press I = P / V formula to calculate the required current value. 18, for the servo drive I can choose the kind of work? Different models do not all exist in all models of drive 19, the drive and system how to ground? A. Do not ground the DC bus non-isolated port or non-isolated signal to ground if there is no separation between the AC power and the drive DC bus (such as a transformer), which may result in equipment damage and personal injury. Because the exchange of public voltage is not on the earth, in the DC bus and the ground may be very high voltage. B. In most servo systems, all common ground and ground are connected together at the signal end. The ground loops created by a variety of earth connections are susceptible to noise and produce a flow at different reference points. C. In order to keep the command reference voltage constant, connect the driver's signal ground to the controller's signal ground. It will also be connected to the external power supply, which will affect the controller and driver work (such as: encoder 5V power). D. Shield grounding is more difficult, there are several ways. The correct shield ground is at the point of reference potential inside the circuit. This point depends on whether the noise source and receiver are grounded at the same time, or floating. Make sure that the shield is grounded at the same point so that the ground current does not flow through the shield. 20. Why can not the gear unit fit exactly with the motor at the standard torque? Many gear ratios far exceed the gear unit torque class, taking into account the maximum continuous torque that the motor produces after it passes through the gear unit. If we were to design each gearbox to match full torque, there would be too many combinations of gearbox internal gears (larger, more materials). This will make the product expensive, and violates the product's "high performance, small size" principle. 21, how do I choose to use a planetary gear reducer or spur gear reducer? Planetary reducer is generally used in a limited space where the need for higher torque, that is, small size and high torque, and its reliability and life expectancy than Spur gear reducer is better. Spur gear reducers are used for lower current consumption, low noise and high efficiency and low cost applications. 22. What is the duty cycle? The duty cycle is the ratio of the motor's working time / (working time + non-working time) during each working cycle. If the load rate is low, the motor is allowed to run at 3x continuous current for a short period of time, generating more power than rated continuous operation. 23, the standard rotating motor drive circuit can be used for linear motor? Generally OK. You can think of linear motors as rotating motors, such as linear stepper motors, brushless, brushless, and AC linear motors. Specific to the supplier consultation. 24, the linear motor can be mounted vertically, do up and down movement? Yes. According to the requirements of the user, we can add the movable slider balance device or install the brake of the brake while installing vertically. 25, in the same platform can install more than one mover? Yes. As long as a few mover does not interfere with each other can. Is it possible to mount multiple mover coils of multiple brushless motors on the same magnetic track? Yes. As long as a few mover does not interfere with each other can. 27, the use of linear motors than the ball screw linear motor What are the advantages? Since there is no mechanical connection between the stator and the mover, backlash, wear and jamming problems are eliminated and the movement is smoother. Highlights the high precision, high speed, high acceleration, fast response, smooth movement, high control accuracy, good reliability, compact size, low profile, long life, maintenance-free features. 28, how to choose electric cylinder, slide, precision platform products? How to calculate the cost? The key to choosing an actuator-type product depends on what requirements you have for the kinematic parameters. You can determine the specific kinematic parameters and other technical conditions based on the application you are looking for, which meets your actual needs and meets both the application requirements Do not leave too much space, otherwise the cost may be several times the standard product. For example, if 0.1mm precision enough, then do not choose 0.01mm parameters. Others, such as load capacity, speed, and so on. Another proposal to the user's selection is, if not necessary, push pull or load, speed, positioning accuracy of the three main parameters do not also require high, because the actuator is a high-precision high-tech mechatronic products , We need to consider the design of the mechanical structure, electrical properties, material properties, materials and handling methods and other considerations and select the appropriate composition of the motor, drive controller and feedback device, as well as different levels of precision rails, screw, support Block and other mechanical systems, so that the overall movement needed to reach the parameters, can be described as a launching the whole body products. Of course, you have high demand for the product needs, we can still meet, but the cost will be increased accordingly