Describe the error accurately
Record whether the axis ends in the wrong place, vibrates without moving, loses position at a particular speed or behaves differently after warming up. Identify whether the error appears on acceleration, steady running, reversal or return. Include the motor, driver, supply and controller codes.
Use normal machine diagnostics and safe access procedures. Do not change wiring on an energised driver, bypass protection or increase settings without the applicable instructions and a competent person responsible for the system.
Holding torque is not running torque
A motor’s holding torque describes a stationary condition. Available torque changes with speed and depends on the motor-driver-supply combination. Compare the required load and acceleration against the relevant torque-speed curve rather than selecting a replacement solely by frame size and holding torque.
Mechanical friction, alignment, binding and transmission load should be included in the investigation. A changed screw lead, gearbox ratio or payload can alter the duty even though the same positioning command is used.
Resonance and command questions
Oriental Motor’s published stepper guidance discusses resonance and position-error troubleshooting. Record the speed range at which the problem occurs and whether it changes with the load or motion profile. A different acceleration profile or technology may be relevant, but changes should follow the responsible engineer’s assessment.
Also check the controller’s intended pulse count and scale, driver command requirements and the actual transmission ratio. A wrong commanded distance can create a repeatable position error without proving the motor has physically missed steps.
Closed-loop stepper or servo?
Closed-loop feedback can reveal or respond to position error, but it cannot create unlimited motor torque or remove a mechanical obstruction. A servo may suit some faster or variable-load applications, with different commissioning, feedback and controller requirements. Establish the reason for changing before selecting a technology.
| Send for review | Include |
|---|---|
| Electrical arrangement | Motor, driver, supply and command interface |
| Motion | Speed, acceleration, travel, reversal and dwell |
| Mechanics | Payload, inertia, transmission and orientation |
| Symptom | Error amount, timing, speed range and recent changes |
For a motor selection enquiry, include quantity and required date as well as the technical information. The servo versus stepper guide explains the wider technology choice. A web guide cannot diagnose the installed machine or guarantee that changing a component will remove the fault.
Sources
- Oriental Motor: stepper troubleshooting basics
- Oriental Motor: stepper operating principles and resonance
Figures are summarised from the sources above and from manufacturers' published data on the date shown. Always confirm against the current datasheet for your exact part.