Short answer: size the drive from the real motion profile — continuous (RMS) and peak current of the chosen motor — then check supply voltage, braking energy, feedback compatibility, network and safety functions. Selecting from the motor catalogue alone is the most common cause of undersized or overheating axes.
1. Start from the motion profile
Define distance, time, dwell and duty cycle for the axis. From the mechanics (masses, gear ratio, pulleys, lead screw), calculate reflected inertia and the torques for acceleration, friction and process load. This gives the motor’s RMS and peak torque and its maximum speed.
2. Match motor and drive
The drive’s continuous current must cover the motor current at RMS torque, and its peak current must cover the maximum acceleration torque — with margin. Check the drive’s peak-current duration, as some drives allow only a short overload.
3. Supply and braking energy
Fast deceleration returns energy to the DC bus. Decide whether a brake chopper and resistor are sufficient, whether axes can share a common DC bus, or whether a regenerative supply is justified.
4. Feedback
Confirm the drive supports the motor’s feedback (resolver, incremental, absolute single- or multi-turn) at the resolution needed. Absolute feedback removes homing after power loss.
5. Control network and synchronisation
For synchronised axes, the motion network must provide deterministic, synchronised cycle times. Check compatibility with the motion controller or PLC.
6. Safety and environment
Safe Torque Off and other integrated safety functions can simplify the machine’s safety circuit. Check ambient temperature, altitude, cabinet space and EMC requirements, including motor cable length.
7. Lifecycle
For machines expected to run for many years, consider the drive series’ lifecycle stage and regional support.
NSPL’s application engineering service sizes drives and motors from your mechanical data.