How to select and calculate the stepping motor?
When stepping motor is selected, the step angle should be matched with the mechanical system so that the pulse equivalent required by the system can be obtained. In the mechanical transmission process, in order to make a smaller pulse equivalent, one can change the lead of the screw, and two can be completed by stepping motor subdivision drive. But segmentation can only change its resolution without changing its accuracy. The accuracy is determined by the inherent characteristics of the motor.
Stepper motor power to choose, we should estimate the load starting frequency of inertia and the mechanical load requirements of the machine, the inertia of stepper motor and frequency matched with a certain margin, the most high frequency can meet the need of fast moving machine.Selecting stepper motors requires the following calculations:(1) calculate the gear reduction ratio; according to the required pulse equivalent, the gear reduction ratio is calculated as follows i:I= (phi.S) / (360. sigma) (1-1) formula, stepping stepping motor angle (o/ pulse), S - screw pitch (mm), Delta - (mm/ pulse)(2) calculate the inertia of the worktable, the screw rod and the gear converted to the motor shaft Jt.In Jt=J1+ (1/i2) [(J2+Js) +W/g (S/2 PI) 2] (1-2), the Jt- is converted to the inertia of the motor shaft (Kg.cm.s2)J1, J2 - gear inertia (Kg.cm.s2), Js - wire inertia (Kg.cm.s2), W- table weight (N), S-, screw pitch (CM)(3) calculate the total torque of motor output MM=Ma+Mf+Mt (1-3)Ma= (Jm+Jt).N/T * 1.02 * 10 - 2 (1-4)Type Ma motor starting acceleration torque (N.m), Jm, Jt-, motor self inertia and load inertia (Kg.cm.s2), n- motor speed required (r/min)
When stepping motor is selected, the output power of stepping motor should be ensured to be greater than the power required by the load. When selecting the power step motor, the load torque of the mechanical system should be calculated first, and the torque frequency characteristic of the motor can meet the mechanical load and have a certain margin to ensure its reliable operation. In the actual work process, the load torque at various frequencies must be within the range of the torque frequency characteristic curve. Generally speaking, the maximum static torque Mjmax large motor, load torque.
