Jul 17, 2017

Mini Stepper Motor The selection of stepping motor

The selection of stepping motor

The stepping motor has three main elements: the step Angle (involving the phase number), the static torque and the current. Once the three factors are determined, the model of stepping motor is determined.

1. Selection of step Angle

The step Angle of the motor depends on the requirement of load accuracy, and the minimum resolution (equivalent) of the load is converted to the motor shaft, and the Angle of each equivalent motor should be measured (including deceleration). The step Angle of the motor should be equal to or less than this Angle. At present, the step distance of the stepping motor in the market is 0.36 degrees / 0.72 degrees (five phase motors), 0.9 degree / 1.8 degree (two, four phase motor), 1.5 degree / 3 degree (three-phase motor), etc.

2. Selection of static torque

It is difficult to determine the dynamic moment of stepping motor. We usually determine the static moment of the motor. The static moment selection is based on the load of the motor, and the load can be divided into inertia load and friction load. A single inertia load and a single friction load do not exist. The two kinds of load should be considered when starting directly (usually at low speed), and when the starting point is accelerated, the main consideration is the inertia load, and the constant speed will be run as long as the friction load is considered. In general, the static moment should be good for two to three times the friction load. Once the static moment is selected, the machine seat and the length of the motor can be determined (geometric size).

3. Current selection

Static torque is the same motor. Due to different current parameters, the operating characteristics of the motor are very different, which can be used to determine the current of the motor (reference drive power and drive voltage) according to the curve of the moment frequency characteristics.

4. Torque and power conversion

The stepper motor is generally used in a larger range and its power is changed. Generally, the torque is used to measure the torque and the power conversion is as follows:

P = Ω m.

Ω = 2 PI n/a 60

P = 2 PI 60 nM /

The P for the power unit for tile, Ω per second angular velocity, the unit as the radian, n for RPM, M for the moment unit for n · M P = 2 PI fM / 400 (half step work) in which f pulses per second (PPS)

2. The attention points in the application

1, the stepper motor is applied to low speed occasions - speed does not exceed 1000 RPM, 6666 PPS (0.9 degrees), had better be in 1000-3000 used between PPS (0.9 degrees c), can work through the reduction gear to make it here, the motor work with high efficiency, low noise.

2. The step motor is best not to use the entire step state, the whole step state vibration is large.

3, due to historical reasons, only a nominal for the 12 v voltage of motor using 12 v, the other motor voltage value is not driving voltage v, can choose according to drive the driving voltage (suggestion: 57 byg adopts dc 24 v and 36 v, 86 byg adopts dc 50 v, 110 byg USES the above dc 110 v), 12 volts, of course, in addition to the 12 v constant voltage driver can also be driven by other power supply, but want to consider temperature rise.