What does the index term of stepping motor mean?

1, number of phases: the number of exciting coils that generate extremely different pairs of N and S magnetic fields. It is often expressed by m.

2. Beat number: the number of pulses required to complete the periodic change of magnetic field or conductive state is represented by n, or refers to the number of pulses required for the motor to rotate by a pitch angle. Take a four-phase motor as an example, there are four-phase four-beat operation modes, namely AB-BC-CD-DA-AB and A-AB-B-BC-C-CD-D-DA-A.

3. Step angle: corresponding to a pulse signal, the angular displacement of the motor rotor is expressed by θ. θ=360 degrees/(number of rotor teeth * number of running beats), taking the conventional two-phase and four-phase motors with 50 rotor teeth as an example. The step angle θ of four beats = 360 degrees /(50*4)= 1.8 degrees (commonly known as the whole step), and the step angle θ of eight beats = 360 degrees /(50*8)=0.9 degrees (commonly known as the half step).

4. Positioning torque: the locking torque of the motor rotor itself when the motor is not energized (caused by magnetic field tooth profile harmonics and mechanical errors).

5. Static torque: the locking torque of the motor shaft when the motor is not rotating under the rated static voltage. This torque is a standard to measure the volume of the motor, which has nothing to do with the driving voltage and power supply. Although the static torque is proportional to the ampere-turns of electromagnetic excitation and related to the air gap between stator and rotor, it is not advisable to excessively reduce the air gap and increase the ampere-turns of excitation to improve the static torque, which will cause motor heating and mechanical noise.

Second, the dynamic index terminology

1, step angle accuracy: the error between the actual value and the theoretical value of each step angle of stepping motor. Expressed as a percentage: error/step angle * 100%. Different running beats have different values, with four beats within 5% and eight beats within 15%.

2. Out-of-step: The number of steps when the motor is running is not equal to the theoretical number. Call it out of step.

3. Misalignment angle: The angle at which the rotor tooth axis deviates from the stator tooth axis, there must be a misalignment angle in the operation of the motor, and the error caused by the misalignment angle cannot be solved by subdivision driving.

4. Maximum no-load starting frequency: the maximum frequency at which the motor can be started directly without load under a certain driving mode, voltage and rated current.

5. Maximum no-load operating frequency: the highest speed frequency of the motor under a certain driving form, voltage and rated current.

6. Operating torque-frequency characteristics: The relationship curve between output torque and frequency measured by the motor under certain test conditions is called operating torque-frequency characteristics, which is the most important among many dynamic curves of the motor and the fundamental basis for motor selection.

Other characteristics include inertia frequency characteristics, starting frequency characteristics and so on. Once the motor is selected, the static torque of the motor is determined, but the dynamic torque is not. The dynamic torque of the motor depends on the average current (not the static current) when the motor is running. The greater the average current, the greater the output torque of the motor, that is, the harder the frequency characteristics of the motor. In order to make the average current as large as possible and the driving voltage as high as possible, a motor with small inductance and large current is used.

7. The * * vibration point of the motor: the stepping motor has a fixed * * vibration area, and the * * vibration area of two-phase and four-phase inductors is generally between 180-250pps (step angle 1.8 degrees) or about 400pps (step angle 0.9 degrees). The higher the motor driving voltage, the higher the motor driving voltage.

8. Motor forward and reverse rotation control: the motor winding rotates forward when energized with AB-BC-CD-DA or (), and reverses when the energizing sequence is DA-CD-BC-AB or ().