A motor’s continuous torque is determined by calculating the root mean square of all the torques. One of the most important factors is the required torque when sizing a motor. Motor torque-speed curves outline two primary areas of permissible torque: continuous and intermittent. Intermittent motor torque is allowed only for a short time and in most cases is the torque required during acceleration.
Torque During Acceleration
The maximum required motor torque often comes when the load is being accelerated. The total torque during acceleration takes into account the inertia of the system being moved and the motor’s acceleration.
Torque During Constant Speed
The motor torque required at constant speed is the sum of the torque needed to drive the load, the preload torque of the screw assembly, and the torque due to friction of the support bearings and seals.Drive torque is primarily influenced by the axial load on the screw and the screw’s lead.
The axial load is not only the process force (drilling, punching, etc.), but also includes the force required to move the load. Since most ball screw assemblies use profiled guide rails to support the load, this will simply be the force that the load exerts radially (downward) times the coefficient of friction of the guide.
Torque During Deceleration
Deceleration torque is simply the torque at constant speed minus the torque due to acceleration.
Post time: Jun-06-2019