Stepper motor with the rapid development of power electronic skills, the function of the frequency control of motor speed indicators can completely reach or even beyond the dc motor speed regulating system. After conditioning input drive pulse frequency and the segmentation parameters to regulate the effect of the stepper motor speed, actually is to manipulate within unit time steps of step motor. A, changes in logarithm variable speed advantages: 1, no additional slip loss, high power; 2, control circuit short, easy to repair, the price is low; 3, cooperate with the stator voltage regulator or electromagnetic slip clutch power can be obtained higher smooth speed regulation. Defects: there are not used to realize stepless smooth speed regulation, and because of the limitation of motor structure and production process, generally can only achieve 2 ~ 3 kinds of logarithm step speed, speed adjustment scale is quite limited. Second, frequency control of motor speed advantages: 1, no additional slip loss, high power, wide speed scale; 2, for low load operation time is longer, or up, stop the frequent occasions, to reach the intention of saving electricity and maintenance of the motor. Defect: skills are mixed and disorderly, the price is higher. Three, commutator motor strengths: 1, have outstanding communication synchronous motor structure brief and dc motor speed control function; 2, low speed with stepper motor power supply voltage, high speed counter potential natural converter, reliable operation; 3, no additional slip loss, high power, suitable for high speed large capacity synchronous motor start and speed control. Defects: low overload capacity, the capacity of original machine cannot give full play to. Four, together string son speed advantages: 1, to speed the process of occurrence of slip energy feedback to use them. High power; 2, equipment capacity and the speed is directly proportional to the size, suitable for 70% ~ 95% of the speed control. Defects: low power factor, harmonic, normal operation without the brake torque, suitable for single quadrant operation load. Five, the stator voltage regulating speed advantages: 1, line brief, equipment is small in size, price cheap; 2, convenient use, repair. Defect: 1, the speed increase slip in the process of loss, the loss of the rotor heat, low power; 2, the relatively small size of speed; 3, require the use of high slip motor, such as specially designed torque motor, so soft, generally applicable to 55 kw asynchronous motor. Six, electromagnetic clutch speed advantages: 1, the brief structure, control equipment capacity is small, cheap value; 2, reliable operation, simple repair; 3, no harmonic trouble. Defect: 1, the speed loss is big, because the electromagnetic slip clutch slip itself is larger, so the highest speed of the output is only 80% ~ 90% for motor synchronous speed; 2, poor control process transfer power all way is converted into heat energy loss, low power. Seven, rotor resistance speed advantages: 1, the skill is low, easy to grasp; 2, low cost of equipment; 3, no electromagnetic harmonic trouble. Defect: 1, the resistance will only have used cast iron. If using liquid resistance for stepless speed regulation, the preventive maintenance, the demand is higher; 2, in the process of speed regulation, the slip power of the additional all into the way of resistance heating loss, low power; 3, small speed regulation.
