By Eileen Harvey
Industrial automation has grown rapidly and with it, the need for reliable cables that can handle high performance, precision and safety requirements. The most essential are servo cables and variable frequency drive (VFD) cables. Both play crucial roles in powering motors, drives and motion control systems. However, they differ in their design, construction and applications.
Among the leading providers of high-performance cable systems is TKD Kabel, a brand renowned for its commitment to quality and innovation. This article delves into the various offerings of TKD Kabel, particularly focusing on their industrial-grade cables designed to optimize the functionality of VFDs. With an emphasis on electromagnetic compatibility (EMC) and robust design, these cables are engineered to meet the rigorous demands of modern machinery and automation systems
What Are Servo Cables?
Servo cables are specially designed to connect servo motors with controllers or drives. They combine power and signal transmission, making them vital in precise motion control applications. They carry electrical power to the servo motor and simultaneously transmit feedback signals from motor sensors (like encoders or resolvers). This provides high precision, low signal loss and flexibility for dynamic movements.
Servo cables are commonly found in robotics, CNC machines, packaging lines and automated conveyors.
What Are VFD Cables?
VFD cables are engineered to connect variable frequency drives to AC motors. These drivers control motor speed by adjusting frequency and voltage, making VFD cables essential for energy efficiency and motor performance. They carry power from the drive to the motor while minimizing electrical noise (EMI/RFI). This prevents interference with nearby sensitive equipment and reduces motor downtime.
They are used in HVAC systems, pumps, compressors and conveyors where energy savings and controlled motor speed are required.
Why Servo and VFD Cables Are Used
VFD cables have emerged as essential components in the operation of sophisticated machinery and control systems. Servo cables facilitate the precise operation of Servo motors, which are integral to applications requiring high accuracy and dynamic response, such as robotics and CNC machinery.
Meanwhile, VFD cables are designed to support variable frequency drives, enabling efficient control over motor speed and torque in a broad range of applications, from HVAC systems to conveyor belts. The unique construction of these cables not only accommodates the specific electrical characteristics required for their respective applications but also addresses challenges such as EMI, heat dissipation and environmental exposure.
Understanding the significance of servo and VFD cables is crucial for engineers and technicians alike, as the proper selection and installation of these cables can greatly enhance system performance, reduce downtime and extend the lifespan of critical equipment.
Construction of Servo and VFD Cables
Servo and VFD cables share several underlying design principles, yet their construction differs to meet the specific performance demands of each application.
Servo cables use fine stranded copper conductors that provide the flexibility required for continuous motion. Their insulation is typically made from special PVC or cross-linked polyethylene to ensure electrical safety. Shielding is provided through braided copper or foil to protect sensitive signals from EMI. The outer jacket is usually an industrial grade PUR or PVC that resists oils, chemicals and abrasion in dynamic environments.
VFD cables are constructed to manage the electrical demands of variable frequency drives. They use XLPE insulated copper conductors capable of handling voltage spikes generated during drive switching. Shielding consists of an overall foil and braid combination that controls electromagnetic emissions and reduces interference. Additional ground wires are included to minimize common mode currents and enhance system stability. Their jackets are formulated to be flame retardant as well as sunlight and oil resistant so they can withstand harsh industrial conditions.
Shielding in Servo and VFD Cables
Shielding is critical because motor and drive systems generate significant EMI. For servo cables, shielding ensures accurate encoder/feedback signals without disruption. For VFD cables, heavy-duty shielding prevents EMI from escaping into surrounding equipment.
Using unshielded or improper cables can cause communication errors, motor failures and downtime.
Applications of Servo and VFD Cables
Servo cables are widely used across motion control and automation environments. They support robotics and automated arms that require precise movement, and they are essential in machine tools such as CNC systems, milling machines and laser cutters. Packaging and textile machinery also rely on servo cables for coordinated motion, while printing presses depend on them for accurate registration at high speeds. Conveyor systems further use servo cables to maintain controlled positioning and smooth material handling.
VFD cables serve a different set of applications focused on motor control. They are commonly used in HVAC fans and blowers where variable speed improves efficiency. Pumps in industries such as water treatment or oil and gas depend on VFD cables for stable power delivery, as do compressors in industrial facilities. Conveyors and mixers benefit from VFD-driven motors for adjustable speed and reduced energy consumption, and many modern energy-efficient motor systems rely on VFD cables to achieve consistent performance with minimized electrical noise.
Standards for Servo and VFD Cables
These specialized cables play a critical role in the transmission of electrical power and signals between controllers and motors, influencing the performance and longevity of machinery across various applications. As industries adopt advanced technologies and strive for improved operational performance, adhering to established standards for servo and VFD cables becomes increasingly crucial. These standards not only ensure compatibility and safety but also optimize system functionality and reduce the risk of failures.
Both cable types comply with international standards to ensure safe and reliable performance. They comply with the UL and CSA safety approvals for North America and with IEC standards for international compliance for industrial equipment. The cables also adhere to the environmental standards of RoHS/REACH and with the CE certification required in Europe.
How to Choose Between Servo and VFD Cables
Choosing between servo and VFD cables begins with understanding the application. Servo cables are the better choice for motion control systems that require both power and feedback, while VFD cables are intended for controlling motor speed and delivering stable power. It is essential to confirm the voltage and power ratings of the motor and drive to prevent overloads and ensure safe operation. Shielding requirements should also guide the decision; installations near sensitive electronics benefit from heavily shielded designs that limit interference. Environmental conditions play a major role as well. PUR jackets provide the flexibility needed for moving applications, while flame retardant jackets that resist UV and oil are recommended for harsh industrial settings. Brand reliability should not be overlooked, and TKD Kabel offers thoroughly tested industrial grade servo and VFD cables suitable for a wide range of demanding applications.
FAQs About Servo and VFD Cables
Q1: Can I use regular power cables instead of VFD cables?
A: No, because standard power cables cannot handle EMI and voltage spikes from VFDs. This can lead to motor failure.
Q2: Are servo and encoder cable the same?
A: Not exactly. Servo cables carry both power and feedback signals, while encoder cables only handle sensor signals.
Q3: How long can VFD cables run?
A: Typically, up to 100 meters, depending on drive specifications and cable shielding quality.
Q4: Do servo cables need special connectors?
A: Yes. They often use hybrid connectors that combine power and signal pins.
Servo and VFD cables may seem similar, but their applications, shielding and construction set them apart. Choosing the right one can significantly improve motor performance, reduce downtime and ensure compliance with safety standards. Whether you need cables for precision motion control or efficient motor power delivery, brands like TKD Kabel deliver trusted solutions.
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.
