Analysis of the moment angle characteristics of stepper motor!
Moment angle characteristic
It refers to the relationship between the static torque T of the stepping motor and the rotor misalignment angle θ in the case of a single pulse and constant current T=f.
The moment angle characteristic is the basic characteristic of the stepping motor. It is very important to measure this characteristic correctly and conveniently, but it still feels difficult to date. People have long wanted to measure the moment angle characteristic of the stepping motor by rotating the induced voltage. However, the relationship between the rotating voltage and the static torque in the stepping motor is complicated.
Moment angle characteristic test
Given an electrical pulse signal, the stepper motor rotor is rotated through the corresponding angle, which is called the step angle of the stepper motor. At present, the step angle of commonly used stepping motors is mostly 1.8 degrees (commonly known as one step) or 0.9 degrees (commonly known as half step). For a progressive motor with a step angle of 0.9 degrees, when we give the stepper motor an electrical pulse signal, the stepper motor turns over 0.9 degrees; for two pulse signals, the stepper motor turns over 1.8 degrees. By analogy, the stepping motor can be continuously operated given the pulse signal continuously. Due to the linear relationship between the electric pulse signal and the rotation angle of the stepping motor, the stepping motor has been widely used in speed control and position control.
Reasonable range of stepper motor heating:
The extent to which the motor is allowed to heat up depends mainly on the internal insulation rating of the motor. Internal insulation properties are destroyed at high temperatures (above 130 degrees). Therefore, as long as the internal does not exceed 130 degrees, the motor will not damage the ring, and the surface temperature will be below 90 degrees. Therefore, the stepper motor surface temperature is normal at 70-80 degrees. The simple temperature measurement method is useful for point thermometers. It can also be roughly judged: it can be touched by hand for more than 1-2 seconds, not more than 60 degrees; it can only be touched by hand, about 70-80 degrees; a few drops of water quickly It is 90 degrees or more.
The main advantages of stepping motor driver subdivision are:
The low frequency oscillation of the motor is completely eliminated. Low frequency oscillation is an inherent characteristic of stepper motors (especially reactive motors), and subdivision is the only way to eliminate it. If your stepper motor sometimes needs to work in the resonance zone (such as arcing), select the subdivision driver. Is the only choice. ? The output torque of the motor is increased. Especially for a three-phase reactive motor, the torque is increased by about 30-40% compared to when it is not subdivided. ? Improve the resolution of the motor. Since the step angle is reduced and the step uniformity is improved, it is self-evident that 'increasing the resolution of the motor'.
