By Eileen Harvey
Servo systems are the backbone of modern automation, robotics and precision manufacturing. At the heart of these systems lies an essential but often overlooked component: servo cables. Power cables are responsible for supplying the electrical energy needed to operate motors, whereas feedback cables transmit positional data to ensure optimal performance. Moreover, encoder cables are key in conveying information about speed and direction, significantly improving the efficiency and responsiveness of servo systems.
These specialized cables are crucial for transmitting both power and feedback signals among servo motors, controllers and encoders, enabling precise motion control. For engineers and technicians involved in the design and upkeep of advanced machinery, grasping the essential aspects of servo cables is essential. As industries continue to embrace automation technologies, a solid understanding of servo cables is crucial for enhancing system performance and achieving operational success.
What Are Servo Cables?
Servo cables are specialized industrial cables designed to connect servo motors to their respective drives and controllers. Unlike standard electrical cables, servo cables handle high voltages and currents (for power), transmit sensitive control signals (for feedback and encoders), withstand continuous motion, bending, twisting and harsh environments, and provide excellent shielding to minimize electromagnetic interference (EMI). This makes them indispensable in industries such as robotics, CNC machining, packaging, textiles, automotive manufacturing and renewable energy systems.
Technical Characteristics of Servo Cables
- Voltage Ratings: Typically, 300V to 1000V, depending on motor power requirements.
- Shielding: Braid, foil or hybrid shielding to minimize EMI and RFI.
- Flexibility: Engineered for drag chain applications and continuous movement.
- Insulation Materials: PVC (general use), PUR (oil/chemical resistance), TPE (high flexibility).
- Standards Compliance: UL, CSA, CE, RoHS certifications.
Types of Servo Cables
Power servo cables deliver electrical power from the servo drive to the motor. They offer high voltage and current capacity and are built with oil heat and chemical resistance along with EMC shielding to minimize noise. These cables are used in robotics conveyors industrial machinery and CNC equipment.
Feedback servo cables carry critical signals from the motor back to the controller including position velocity and torque data. They support low-level analog and digital signals and use double shielding for EMI resistance along with twisted pairs for signal integrity. They are used in closed-loop motion systems that require precision and stability.
Encoder servo cables connect encoders to controllers and transmit digital pulses or absolute position data. They support high-frequency signal transmission and use shielded twisted pairs to reduce crosstalk. They are designed for continuous flexing in dynamic machinery and are used in robotics CNC machines and any system that requires exact motor positioning.
Servo Cables vs. VFD Cables – Key Differences
Among the various types of cables used, servo cables and variable frequency drive (VFD) cables stand out due to their specific applications and functional characteristics. While both are integral to the operation of motors and drives, they serve distinctly different purposes and are designed to handle unique electrical and environmental demands.
Servo cables are primarily utilized in closed-loop control systems, where precise feedback and rapid response times are critical for ensuring accurate motion control in servo motors. In contrast, VFD cables are tailored for variable frequency drives, designed to efficiently manage the speed and torque of AC motors while minimizing electromagnetic interference.
While both are designed for motor control, they serve different purposes:
- Servo cables = Power + feedback/encoder signals.
- VFD cables = Mainly for VFDs, optimized for power delivery with EMC protection.
Applications of Servo Cables
Servo cables are used across a wide range of applications. In robotics and automation they support high-precision movement. In CNC machinery they enable exact cutting drilling and shaping. Textile and packaging machines rely on them for fast repetitive motion. Automotive manufacturing uses servo cables for robotic arms and conveyors. In renewable energy they support wind turbines and solar tracking systems.
Best Practices for Selecting and Using Servo Cables
When selecting and using servo cables it is important to match the cable type to the motor’s voltage and current rating. Environmental conditions such as temperature oil and chemicals should be evaluated carefully. Shielded feedback and encoder cables should be used to protect against EMI. For dynamic applications it is best to choose PUR or TPE jacketed cables with drag-chain ratings. And finally, for heavy-duty VFD/servo applications, opt for Kaweflex EMC-optimized servo cables.
Industry Fact:
Studies show that over 70% of servo motor failures are caused by cable/connectivity issues, not the motor itself. Investing in high-quality cables extends equipment life and reduces downtime.
Servo cables serve as the essential conduits for motion control systems, facilitating precise, efficient and dependable motor operation. For maximum reliability, we recommend TKD Kabel industrial-grade cables and Kaweflex EMC-optimized servo/VFD cables available at L-com.
Explore the full range of TKD Kabel through L-com. We’ll fill your orders fast, with same-day shipping on all qualified, in stock, online orders received Monday through Friday before 5 p.m. EST. For TKD-related inquiries, connect with our U.S-based TKD expert Eileen Harvey at eharvey@infiniteelectronics.com.
