Among many cutting equipment, the motors used in Chengdu portable CNC flame cutting machines are stepper motors and AC servo motors. For portable flame cutting machines, the power of stepping motors can meet the transmission requirements of CNC cutting machines, but Some customers still choose AC servo motors, why are there such differences?
A motor or a fully digital AC servo motor is used as the execution motor. Although the two are similar in control mode (pulse train and direction signal), there are large differences in performance and application. Now compare the performance of the two.
1.The control accuracy of the two motors of the portable flame cutting machine is different
The step angles of two-phase hybrid stepping motors are generally 3.6 ° and 1.8 °, and the step angles of five-phase hybrid stepping motors are generally 0.72 ° and 0.36 °. There are also some high-performance stepper motors with smaller step angles. For example, a stepping motor for a slow-walking machine tool has a step angle of 0.09 °; a three-phase hybrid stepping motor whose step angle can be set to 1.8 °, 0.9 °, 0.72 °, 0.36 ° through a dial switch , 0.18 °, 0.09 °, 0.072 °, 0.036 °, compatible with the step angle of two-phase and five-phase hybrid stepping motors.
The control accuracy of the AC servo motor is guaranteed by the rotary encoder at the rear end of the motor shaft. Taking the AC servo motor as an example, for a motor with a standard 2500-line encoder, the pulse equivalent is 360 ° / 10000 = 0.036 ° because the drive uses the quadruple frequency technology. For a motor with a 17-bit encoder, each time the driver receives 217 = 131072 pulses, the motor makes one revolution, that is, its pulse equivalent is 360 ° / 131072 = 9.89 seconds. It is 1/655 of the pulse equivalent of a stepping motor with a step angle of 1.8 °.
2. Performance comparison between stepper motor and AC servo motor
Stepper motor is a kind of discrete motion device, which has essential connection with modern digital control technology. In current domestic digital control systems, the application of stepper motors is very wide. With the advent of all-digital AC servo systems, AC servo motors are increasingly used in digital control systems. In order to adapt to the development trend of digital control, stepper motors are mostly used in motion control systems.