Stepper motor stepper motor as the optical rotation (General is 60 to)Synchronous motor, each change multiple motor stator current optical activity can promote the motor rotor turn 1. 9 degrees from step Angle, so as electric pulse data signals change for angular displacement or line displacement of electric actuator. In fact, the operation of stepper motor key formed by through the flow of electric motor stator torque drive motor rotor. Electric mechanical and electrical flow operation shall be conducted by the step motor controller, convert the differential signal of control board sent it into the angular displacement of the motor, so you can step into the drive as a power amplifier, its key daily mission is based on PWM demodulator motor operation all necessary electrical flow. Stepping drive stepper motor operation the power flow of the key by motor's own motor stator resistor, inductor and stepping fitness counter electromotive force formed in the whole process of the damage. Stepper motor inductance and power flow is relatively small, damage of electric discharge or larger motor rotor fitness movement in the motor stator counter electromotive force. So the key analysis counter electromotive force of the damage to the motor torque. Average operating motor when the fundamental wave of electromotive force is sine wave formation, its formula is: E = pφ mω，sin(θT)P in great for stepper motor, p = 60; φM for the back emf induction motor constant, associated with the raw material of motor rotor is commonly used, & omega; T for the angular velocity of the motor rotor, & theta; T for motor rotor position. Stepper motor greatly are many larger than the general motor synchronous motor or communication, as a result, the speed is more than can form double counter electromotive force, in addition to the motor rotor, the greater the back emf constant is, the more big, formed by the counter electromotive force will be with number of ascension. Stepping drive daily mission is based on load demodulation of motor stator all necessary electrical flow, in fact is to consider the following equation of physics: U + L dI/dt + E = IR, the operating voltage U is necessary based on PWM demodulation is formed, in each PWM cycle time T, it is necessary to measure the on-off time ton, promote U = ton/T Ubus (0≤ton≤T)。 Because the resistor R and inductance L of the motor is relatively small, counter electromotive force is the key of the damage step drive elements, can understand the general 87 stepper motor according to the experiment in 400 turn up and down, the counter electromotive force formed by the assembly out of 47 v, which is formed by the 67 motor in 350 turn up and down counter electromotive force in 47 v. Motor counter electromotive force beyond the given busbar voltage, PWM controller demodulation into & other; Saturation & throughout; Situation, can't show the motor kinetic energy, which in turn is the digestion and absorption kinetic energy, so the torque of the motor will be slow attenuation coefficient; Step speed faster and faster, the more it is easy to throw. Therefore stepping drive the selection of the operating voltage is related codes by using a model of the drive motor, stepper drives the higher operating voltage, the PWM demodulator category, the greater the can counter electromotive force, which is formed by the compensation of the motor speed can improve motor high speed running. High torque of the motor is necessary step motor controller with high pressure can give full play to its high speed characteristic, for example 87 stepper motor under 28 v specification high speed characteristic will than 67 motor, under the fundamental reason for high speed specification 87 motor is very easy to form relatively high counter electromotive force, promote the stepper drive PWM demodulation quickly into the saturated zone, electrical flow greatly attenuation coefficient, the formation of torque rapid attenuation coefficient. Under the high pressure specification, 87 the torque of the motor will emerge, form the torque is larger than 67. It is stepping drive and stepper choose selection needed to pay attention to essential problem.
