stepper motor Number of pulses
1. The angle of rotation of the motor is proportional to the number of pulses;
2. When the motor stops, it has the maximum torque (when the winding is excited);
3. Because the accuracy of each step in three to five percent, and will not be one step error accumulated to the next step and thus have better position accuracy and motion repeatability;
4. Excellent start and stop and reverse response;
5. Because there is no brush, high reliability, so the life of the motor depends only on the bearing life;
6. The response of the motor is determined only by the digital input pulse, so that open-loop control can be used, which makes the structure of the motor relatively simple and costly;
7. Simply connecting the load directly to the shaft of the motor can also be rotated at very low speed.
8. Since the speed is proportional to the pulse frequency, there is a wide range of speed.
1. If the control is not easy to produce resonance;
2. Difficult to run to a higher speed. 1, step angle accuracy:
The error between the actual value of the step motor and the theoretical value of each step. Expressed as a percentage: error / step angle * 100%. Different running beat the value of different, four-beat operation should be within 5%, eight-beat operation should be less than 15%.
2, out of step:
The number of steps when the motor is running is not equal to the theoretical number of steps. Called out of step.
3, offset angle:
The rotor tooth axis offset the angle of the stator tooth axis, the motor operation must exist offset angle, the error caused by the offset angle, the use of subdivision drive is not resolved.
4, the maximum no-load starting frequency:
Motor in a certain drive form, voltage and rated current, without load in the case, can directly start the maximum frequency.
5, the maximum no-load operating frequency:
Motor in a certain drive form, voltage and rated current, the motor without load the maximum speed of the frequency.
6, running torque characteristics:
The curve of the output torque and frequency of the motor under certain test conditions is called the running moment characteristic, which is the most important of many dynamic curves of the motor and the basis of the motor selection. As shown below:
Other features include frequency characteristics, starting frequency characteristics.
Once the motor is selected, the static torque of the motor is determined, and the dynamic torque is not the same. The dynamic torque of the motor depends on the average current (not the quiescent current) when the motor is running. The larger the average current, the greater the motor output torque The harder the frequency characteristics.
Among them, the curve 3 current maximum, or the highest voltage; curve 1 current minimum, or the lowest voltage, curve and load the intersection of the maximum speed point for the load. To make the average current large, as much as possible to improve the drive voltage, so that the use of small inductor high current motor.