The biggest issue that surrounds the use of step motors and tarnishes its unlimited potential is step losses. However, such losses can be avoided and corrected. The operation of a step motor is best described as open loop. Although, the choice of the driver and motor are crucial, there are some other factors that can also result in the occurrence of step losses.
The selection of the stepper motor is based on a set of three rules. Firstly, the stepper motor must meet the torque/speed requirements of the application. Secondly, the safety factor of the motor concerned must be at least 30%. Finally, no external events must be able to halt the application.
It is necessary to realize that the working of a stepper motor is entirely different from that of a DC motor. Therefore, the only parameters that determine the performance of the stepper motor are the torque/speed. The next level of scrutiny is to check for step losses that may occur during operation. One of the most difficult aspects of stepper motor operation is that it does not have a feedback system, which makes fault detection extremely difficult.
An analysis of the mode of operation is different for different motion profiles. Several failure modes exist for the stepper motor. It may fail to start during the start/stop mode or terminate with a steady acceleration ramp. These scenarios require a strong assessment of the cause and a resolution can appropriately be devised depending upon the analysis.
The construction of the stepper motor is such that it will never miss a single step. It loses steps in multiples of four. However, if the stepper motor losses steps that are lesser than four, then a commutation issue can be suspected. This abnormal functioning of the motor can be a result of the difference between the position of the real motor and the position of the counter. In order to address this issue, the motor must be switched off, and the counter must be reinitialized. The device must then be switched on in the same position.
Some external events like Back Driving and Pay Load increase with time can also lead to losses. However, effective solutions to counter these issues are also available. To learn more about the stepper motor and its applications, contact Sinotech or view our stepper motor catalog.