discount stepper motors torque decreases with increasing speed
The stepper motor torque decreases with increasing speed, which is essentially the performance of the stepper motor's torque frequency characteristics.
Its characteristics: starting from the maximum load torque (static torque), as the control pulse frequency increases, the speed of the stepping motor gradually increases, while the load capacity decreases.
The root cause of the decrease in the characteristics of the momentary frequency:
1, winding inductance effect:
Both the rise and fall of the current in the windings takes a certain amount of time. When the pulse frequency is low, the period of energization of the winding is longer, the average value of the current is larger, the energy obtained by the motor is higher, and the higher torque can be maintained; when the pulse frequency is higher, the period of energization in the winding is shorter. The average value of the current is small, the motor obtains less energy and the torque decreases.
2. The effect of back EMF resistance:
As the frequency increases, the rotor speed increases, and the additional rotational potential generated in the stator windings causes the motor to be subjected to greater damping torque, and the vortex loss of the core also increases.
There are two ways to improve the high frequency performance measures of the moment frequency characteristics:
1. Decrease the time constant to increase the resistance. In order to ensure that the current in the energized circuit is constant, the power supply voltage is also increased while increasing the resistance.
2. Improve working methods. The multi-phase excitation mode is used, for example, the four-shot of the two-phase stepping motor changes eight beats. The multi-phase excitation mode extends the time for energizing each phase, and the motor can obtain more energy, increasing the torque output at high output.