Customizing Stepper Motor Rated Current: Possibility and Implications

The rated current of a stepper motor typically refers to the maximum continuous current that each phase winding can withstand in a static (locked) state. Simply put, it is the maximum phase current at which the motor can operate continuously without exceeding a safe temperature. Clearly, modifying the coil specifications of the windings alters the motor's rated current, and STEPPERONLINE offers such customization services.

However, customizing the rated current is not simply a matter of changing a number; it triggers a series of chain reactions affecting multiple core performance characteristics of the motor, most notably its speed and torque. The following is a brief explanation considering low-speed and high-speed torque:

• Low-Speed Torque: In the low-speed region, torque is primarily proportional to the current. A motor with a higher rated current generally possesses higher holding torque and low-speed torque. Conversely, a motor with a lower rated current typically has lower holding torque and low-speed torque.
• High-Speed Torque: This is the area most significantly affected. The inductance of the windings impedes rapid changes in current. A high-current motor (with fewer coil turns) has lower inductance, allowing the current to build up more quickly.

Therefore, during high-speed rotation, the coil can reach the rated current value faster within the available energization time, resulting in slower torque decay at high speeds and better high-speed performance. Conversely, a low-current version (with more coil turns) has higher inductance. At high speeds, the current rises more slowly, causing torque to drop off very rapidly.

Updated on: 29/09/2025