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Enterprise introduction
  • 1 how to correctly choose the servo motor and stepper motor?

    Answer: mainly depending on the specific application and decide, simply said to identified: the nature of the load (such as horizontal or vertical load, etc.), torque, moment of inertia, rotational speed, accuracy, and acceleration and deceleration requirements, the upper control requirements, such as the requirement of port interface and communication, the main control mode is position and torque or speed mode. The power supply is DC or AC power supply, or battery power, voltage range. According to determine the motor and model with drive or controller.

    2 select the stepper motor or servo motor system?

    Answer: in fact, choose what kind of motor should be based on the specific application situation, has its own characteristics.

    3 how to use stepper motor driver?

    Answer: according to the current of the motor, with greater than or equal to the current drive. If the low vibration and high accuracy, can be matched with subdivision driver. The torque of the motor, as far as possible with the high voltage driver, in order to obtain good performance of high speed.

    4.2 phase and 5 phase stepper motors have the difference, how to choose?

    Answer: the 2 phase motor at low speed and low cost, but the larger shock, high speed torque decreases quickly. Five phase motor is less vibration, high speed performance, than the 2 phase motor speed high 30-50%, but in some occasions to replace the servo motor.

    5 when used in DC servo system, what is the difference between it and AC servo?

    Answer: into a DC servo motor brush and brushless motor.

    Brushless motor, low cost, simple structure, start torque, wide speed range, easy control, need to maintain, but maintaining convenient (f brush), electromagnetic interference (EMI), on the environment required. So it can be used for cost sensitive general industrial and civil applications.

    The brushless motor has the advantages of small size, light weight, high power, fast response, high speed, small inertia, smooth rotation, torque stability. Control complex, easy to implement intelligent, the electronic commutation is flexible, can change the square wave or sinusoidal commutation. Motor maintenance free, high efficiency, low operating temperature, electromagnetic radiation is very small, long life, can be used in various environments.

    AC servo motor and brushless motor, divided into synchronous and asynchronous motors, at present motion control generally used synchronous motor and its power range big, can achieve great power. Large inertia, the maximum rotation speed is low, and with the rapid increase of power reduction. Therefore suitable for low-speed applications running smoothly.

  • From the perspective of control, the speed control and torque control is independent control function.

    The target is the physical quantity speed control stepper motor speed, the target physical quantity torque control torque of stepping motor.

    From the point of view of the principle of control and speed control is on the speed actual value for the closed-loop control, the speed regulator is in closed state, through its output to guide current regulator, by the current regulator to control the stepper motor current, thus timely regulates the stepper motor torque, the stepper motor always tracking the stepping motor speed setting.

    Velocity model is that the frequency converter to control the step motor speed for the purpose, this time stepping motor torque must be to keep up the pace of the adjustment. So the control system and a ring of speed, the inner current loop. Output speed loop current loop is given (torque given), also known as the torque loop current loop.

    Torque mode refers to the frequency converter is to control the stepper motor output torque for the purpose, the size and speed of the external load size related. The general inverter speed loop, current loop only, given directly to the external current loop as torque setting. In order to prevent speeding, many high-end inverter with speed outer loop overspeed limit, which is a kind of enhanced type torque mode. At the same time, the speed loop only a limit to maximum speed, current loop still play a leading role. Mountain Club motor.

  • Stepper motor driver is a kind of electrical pulses into angular displacement of the actuator. When the stepper driver receives a pulse signal it will drive a step motor according to set the direction of rotation of a fixed point (called "step angle"), its rotation is in fixed angle step by step operation. Can by controlling the pulse number to control the amount of angular displacement, so as to achieve the purpose of accurate positioning; at the same time can by controlling the pulse frequency to control the motor rotation speed and acceleration, so as to achieve the purpose of speed regulation and positioning. Widely used in engraving machine, crystal grinding machine, middle CNC machine, EEG embroidery machine, packaging machinery, fountains, dispensing machine, cut material feeding system of high resolution of large and medium-sized CNC equipment.

    Phase stepper motor refers to the number of the motor coil group, used a two-phase, three-phase, four phase, five phase stepper motor. Number of motor phase are different, the step angle is different, the general two-phase motor step angle is 180 degrees, three-phase 1.2 degrees, five phase of 0.72 degrees. In the absence of subdivision drive, users mainly depends on the number of different phase stepper motor to meet the requirements of step angle. If you use a subdivision driver, the number of phases will become meaningless, users only need to change the fine fraction on the drive, you can change the step angle.

    After subdivision driver will be the running performance of the motor have a qualitative leap, but all this is generated by the drive itself, and the motor and control system. When in use, the user only needs to pay attention is the stepper motor step angle changes, the dots on the control system of step signal frequency effect, because subdivision back stepping motor step angle smaller, step into the frequency of the signal to a corresponding increase in. To 1.8 degrees step motor as an example: drive in the half step state step angle is 0.9 degrees, and in ten subdivision step angle for 0.18 degree. This requires that the motor speed is the same, the control system the step into frequency signal in ten segments for half step runs 5 times.

    General precision stepper motor step angle of 3~5%. Stepper motor step deviation will not affect the accuracy of the next step, so precision stepper motor is not cumulative.

  • 1, the two half couplings in the middle of the interval is too wide, resulting in diaphragm is subjected to large axial force, the cutter hole or stranding bolt wear, resulting in abnormal sound;

    2, two axial offset coupling deflection angle is too large or too large, will produce vibration and noise caused by the operation of equipment;

    3, the active and passive end end speed differences will produce vibration and noise caused by the operation of equipment;

    4, the motor speed encoder failure, caused by the rotational speed of the motor speed, and make the diaphragm coupling noise.

  • Precision planetary gear correct installation, use and maintenance of the reducer, is an important link to ensure the normal operation of machinery and equipment. Therefore, in the installation of planetary gear reducer, must be strictly in accordance with the following installation related matters, serious assembly.

    The first step: confirmation of the motor and the speed reducer is intact and check the motor and the speed reducer is connected, the size of each part if there is a match.

    The second step: unscrew the screws on the reducer flange lateral dust hole, adjustment system PCS clamping ring so that the side hole and the dust hole alignment, insert hexagon screw. Then, take the motor shaft key. Before installation should be motor input shaft, positioning lug boss and decelerating machine is connected with parts of the anti rust oil, wipe clean with a gasoline or zinc sodium and water.

    The third step: the motor and reducer into natural connection. Connection must ensure decelerating machine output shaft with the output shaft of motor concentricity consistent and two lateral flange parallel so as to prolong the service life, and obtain the ideal transmission efficiency and low noise. In addition, the installation is prohibited by a strike, axial and radial force to prevent excessive damage to the bearing or gear. Must will be installed after tightening the bolts tightened again tightening bolt.

    The fourth step: the speed reducer is installed after the hand rotation should be flexible, non card lag phenomenon. Before starting the fastening screw connection, no-load test shall be not less than 2 hours, the operation should be smooth, no impact, vibration, noise and leakage phenomenon, found that should be ruled out in a timely manner. Use should regularly check whether the loosening of the fastener, to ensure the normal operation.

  • Inverter and the servo driver are all commonly used electrical equipment, but the same is control motor frequency is why two different electrical equipment! The following will be from the three aspects of inverter, servo motor control and motor are introduced and compared.

    The inverter:

    Simple inverter only conditioning communication motor speed, then can open loop to loop to control method and frequency converter and decide, this is traditional V / F control method. Now many frequency now, after the establishment of mathematical model, the communication of motor stator magnetic field UVW3 phase transformation to control motor speed and torque of the two current components, now most to the famous brand of torque control inverter are used such methods to manipulate the control torque, the UVW each phase output to current detection equipment Jiamoer effect, the sampling reaction to form a closed loop negative reaction to the current loop PID conditioning; AFSEN of frequency conversion proposed and this method is not the same as the direct torque control skills. This can not only control the speed of the motor can also control the motor torque and speed and control precision is superior to that of the V / F control, encoder reaction can also be added with, add time control accuracy and echo characteristics better many.


    Servo motor of the materials, the structure and the processing technology is far higher than drive inverter AC motor (usually AC motor or constant torque, constant power and other types of variable frequency motor), that is to say when the driver output current, voltage, frequency change quickly of power, servo motor can power basis change echoed the action for change, response and anti overload ability is far higher than that of AC motor drive inverter, motor the distinction is that functions as both are not the same. That is to say not variable frequency output cannot change so fast power signal, but the motor itself is no response, so in the conversion of the internal algorithm set in order to maintain the motor do corresponding overload set. Of course, if not set inverter output capacity is still limited, some excellent performance of inverter can direct drive servo motor.

    The servo actuators:

    Servo drive in carrying out the conversion skills under the premise, interior of the drive current loop, speed loop and position loop (converter without the ring) are than usually inverter more accurate manipulation skills and algorithms, function also than traditional servo strong many, the main point to accurate position control. After the pulse sequence sent by the host controller to control the speed and range (of course, some servo internal integrated control unit or through communication bus directly to the range, speed and other parameters of the set is in the drive), drive the internal algorithm and faster and more accurate design calculation performance and more excellent electronic devices to more superior to the inverter. PLC training class

    One important difference between servo and frequency is:

    No frequency encoder, there must be a servo encoder, electronic commutation, AC servo technology itself is reference and the application of frequency conversion technology, the frequency control mode of PWM mode based on DC motor servo control on imitate DC motor to achieve, that is to say this part of AC servo motor is inevitable frequency: PLC data conversion is 50, frequency 60HZ AC DC rectifier first, and then through the door of the control transistors (IGBT, IGCT) for pulse electric adjustable frequency waveform similar to Yu Zheng by cosine carrier frequency and PWM control inverter, the frequency is adjustable, so the AC motor speed can be adjusted (n=60f/2p, n speed, f frequency, P log).