7+ common servo motor issues: Causes and solutions

Causes

When a servo motor fails to respond to control commands, the cause is often related to the power supply or system connections. A power outage, poor contact, or a broken cable between the driver and the motor can prevent the motor from receiving power or control signals. Additionally, driver malfunctions or internal motor damage can cause the system to completely stop working.

Solutions

If you encounter this servo motor issue, begin by checking and troubleshooting the power supply, ensuring that electrical connectors are properly connected and receiving a stable power supply. Next, inspect the power cable and servo cable for any breaks or loose connections, and reconnect or replace them if necessary. If the wiring system is functioning normally, proceed to inspect the driver and motor to identify the parts that need repair or replacement.

Causes

Overheating commonly occurs when servo motors operate continuously under heavy load or in environments with poor heat dissipation. Additionally, cooling system malfunctions or inadequate ventilation can also cause heat to build up in the motor and driver.

Solutions

What you need to do is reduce the operating load if the servo motor frequently operates near or above its rated power. At the same time, you should check the cooling system and improve heat dissipation conditions, such as adding fans or optimizing the ventilation design. This will also contribute to extending the lifespan of both the motor and the driver.

Causes

Reduced positioning accuracy is often related to errors from the encoder or improperly calibrated control parameters. In addition, mechanical structure problems can also cause positional inaccuracies in the positioning system.

Solutions

Check the signal from the encoder to ensure that position data is being transmitted accurately to the driver. Simultaneously, review and fine-tune the position, speed, and acceleration control parameters. If mechanical system problems occur – such as a loose or worn drive chain – maintenance or replacement of the relevant components is necessary.

In addition to the typical issues mentioned above, operators may encounter other problems when using servo motors, such as:

Encoder phase issue: The encoder phase needs to be recalibrated, and the encoder must be installed correctly.

Motor commutator issue: The commutator surface needs to be inspected to ensure flatness. If the surface is worn or uneven, it needs to be remachined or replaced.

Motor brush issue: Check the contact between the carbon brushes and the commutator. If sparking occurs or the carbon brushes are worn, replace them with new ones.

In summary, servo motors can experience various problems during operation, ranging from electrical and control issues to mechanical failures. Inspection and troubleshooting should be based on each specific situation to correctly identify the cause and apply appropriate corrective measures. Furthermore, regular maintenance plays a crucial role in maintaining operational efficiency and extending the lifespan of the equipment.

Servo cables are a crucial component in servo motors, ensuring smooth system operation with stable signal transmission. Let's explore some basic information about this type of cable below:

Functions of servo cables

Servo cables are industrial cables that enable reliable communication and power transmission between servo motors, drives, and control units. Key functions of servo cables include:

• Delivering power to servo motors under high-voltage and high-current operating conditions
• Carrying control, feedback, and encoder signals with high transmission accuracy
• Maintaining performance under continuous flexing, torsion, and repetitive motion
• Reducing electromagnetic interference (EMI) through effective shielding technologies

Thanks to these capabilities, servo cables are widely deployed in automation-intensive industries, including robotics, CNC machining, packaging equipment, textile manufacturing, automotive production, and renewable energy applications.

Technical specifications of servo cables

Rated voltage: Typically 600V to 1000V, depending on depending on the motor's power requirements.

Shielding layer: Braiding, metal foil, or a combination of both to minimize electromagnetic interference (EMI) and radio frequency interference (RFI).

Flexibility: Designed for chain drive and continuous motion applications.

Insulation materials: PVC (general purpose), PUR (oil- and chemical-resistant), TPE (high flexibility)

Compliance standards: UL, CSA, CE, RoHS certified

💡Explore how screened cables can reduce harmful bearing currents

Common types of servo cables

Power servo cables

Power servo cables are used to deliver electrical power from the servo drive to the motor. Designed to handle high voltages and currents, they also offer resistance to oil, heat, and various industrial chemicals. In addition, EMC shielding helps reduce electromagnetic interference and ensures reliable operation. These cables are widely used in robotic conveyor systems, CNC machines, and other industrial equipment.

Feedback servo cables

Feedback servo cables carry essential data from the motor back to the servo drive, including information related to position, speed, and torque. They are designed to transmit low-level analog and digital signals with high accuracy. To maintain signal quality, these cables typically incorporate double shielding and twisted-pair conductors that help minimize electromagnetic interference. They are commonly found in closed-loop motion control systems where precision and stability are critical.

Encoder servo cables

Encoder servo cables connect the encoder to the servo drive and transmit digital pulse signals or absolute position data. Built for high-frequency signal transmission, they utilize shielded twisted-pair conductors to reduce crosstalk and preserve signal integrity. Their flexible construction allows them to withstand continuous bending in dynamic applications, making them suitable for robotics, CNC machine tools, and other systems that require accurate motor positioning.

Additionally, depending on the application, servo cables are further divided into fixed cables (used for stationary machines) and chain-driven cables (bending-resistant cables) for CNC machines and robotic arms that require continuous movement.