In industrial automation, servo motors are essential for achieving high-precision and high-speed motion control. However, even in the most advanced systems, technicians often encounter a common issue: the servo motor doesn’t move. When this happens, it can halt production, create confusion, and delay timelines. This article explores the most frequent causes behind a non-moving servo motor and outlines practical solutions to get systems back online quickly.
Common Symptoms When a Servo Motor Doesn’t Move
Before diving into diagnosis, it’s important to identify how the issue presents. The following are common signs that a servo motor doesn’t move:
No motion when power is applied
Motor doesn’t respond to motion commands
Encoder shows no feedback or abnormal signals
Driver is powered on but displays an alarm or “disabled” status
Holding torque is active but the shaft doesn’t rotate
Recognizing these symptoms is the first step in efficiently troubleshooting servo motor problems.
Top Reasons Why a Servo Motor Doesn’t Move
Power Supply Issues
One of the most common reasons a servo motor doesn’t move is unstable or incorrect power supply. Loose connections, missing phases, or voltage drops can all prevent the driver from functioning correctly. Use a multimeter to verify the presence and stability of input voltage across all phases or DC terminals.
Missing or Incorrect Control Signals
If the controller (e.g., PLC or motion card) fails to send valid motion commands, the servo motor won’t react. Check whether the system is sending speed, position, or torque commands and whether the driver is actually receiving them. Also verify that communication protocols like EtherCAT, CANopen, or Modbus are correctly configured and connected.
Servo Enable Signal Not Active
Many servo systems require an external “enable” signal before the motor can operate. If the enable input is disconnected, set to the wrong logic level, or not recognized by the driver, the motor will remain idle. Make sure the enable signal is wired properly and matches the driver’s requirements.
Driver Alarm or Lockout
If the driver has detected an abnormal condition—such as overcurrent, overvoltage, or overheating—it may go into protection mode and shut off output to the motor. When a servo motor doesn’t move, always check the driver display or connected software for alarm codes, and follow the manufacturer’s troubleshooting instructions.
Encoder Feedback Failure
A faulty or disconnected encoder can prevent the servo system from recognizing the motor’s position. This causes the driver to disable output as a safety precaution. Inspect encoder cables, connectors, and shielding. If available, swap in a test encoder to verify the fault.
Incorrect Parameter Settings
Improperly configured parameters—such as speed limits set to zero, invalid positioning targets, or the wrong control mode—can cause the servo motor not to move. Use the driver software or HMI to review key parameters, including mode selection (position/speed/torque), acceleration profiles, and motor limits.
Step-by-Step Checklist for Troubleshooting a Non-Moving Servo Motor
When faced with a servo motor that doesn’t move, follow this logical checklist:
Confirm power supply is present, stable, and within specifications
Check the enable signal and ensure the driver is not in standby or disable mode
Verify that the controller is issuing proper commands
Look for driver alarm codes and review the alarm history or logs
Inspect encoder wiring and feedback signal integrity
Connect diagnostic software to monitor driver status in real time
Test the motor and driver separately if hardware failure is suspected
How to Prevent Servo Motor Downtime
To avoid future occurrences where the servo motor doesn’t move, consider these best practices:
Perform regular inspections on power and signal cables
Keep control cabinets clean and moisture-free
Configure motion profiles and limits according to real application needs
Avoid mechanical overload and check for tight couplings or jamming
Train operators to recognize early signs of malfunction and know basic restart procedures
Solving the “Servo Motor Doesn’t Move” Issue with Confidence
When a servo motor doesn’t move, it’s usually not a complex failure—it’s often a small oversight in signal, power, or settings. By following a structured troubleshooting process, most issues can be resolved quickly and efficiently. A stable servo system depends on reliable wiring, correct parameter settings, proper communication, and environmental awareness.
X-TEAM provides high-performance servo motors and drivers designed for robust, real-world industrial environments. With advanced diagnostics and user-friendly tuning tools, our solutions help engineers minimize downtime and maximize control precision.