The selection of the correct servo cable selection checklist for new machine designs is vital to get the correct electrical stability, mechanical reliability and EMC performance from concept to first prototype. At Hulk Electric, we support OEM engineers in their specification of high flex servo motor cables, encoder cables, and hybrid solutions that fit the exact motion profile, environmental demands, and drive requirements – and prevent costly redesign later.
This practical checklist helps guide the design team every step of the way and provides emphasis on real-world considerations such as continuous flex life, shielding effectiveness and compliance. Following it makes it possible to deliver machines that operate in highly demanding automation environments, and to make time to prototype.
Stage 1 – During Concept: Define Motion and Cable Roles
Identify Servo Axes and Motion Profiles
Start by sketching and noting the motion of each servo axis (static positioning, occasional adjustment, continuous linear movement along drag chains, torsional rotation along robotic arms, or combined 3D motion).
This is the base to consider for flexibility needs. The high-cycle applications are performed with special high-flex servo cables and static runs may be performed with more economical construction. Correct profiling early means no underspecifying of cables that fail in production.
Distinguish Servo Cable Categories
There are generally three types of cables used in a servo system: a servo power cable that supplies power to drive the motor, a servo encoder/feedback cable for more precise signal transmission and a servo brake cable for holding functions.
Servo motor cables need to deliver high power while supporting a clean signal with low voltage. Hulk Electric’s servo & motor cables are precision made to meet these two requirements.
Decide Architecture: Separate vs Hybrid Cables
Discuss the pros and cons of having separate power and feedback cables or of using approved hybrid single-cable designs.
Hybrid designs minimize the number of cables needed in energy chains and make routing easier, but require close coordination between the drive/motor system being used. This choice has consequences for the choice of connectors, fill ratios of the carrier, spare parts strategies, and overall EMC performance.
Stage 2 – Electrical Requirements and Drive/Motor Matching
Voltage Class and Insulation Requirements
Select the cable voltage rating (usually 300V, 600V, 1000V) that is appropriate for your servo system. Electrical stability is assured under high electrical peak loads and voltage spikes found in industrial drives by the correct thickness and type of insulation.
Conductor Size and Current Capacity
Determine conductor cross-section from continuous and peak motor current, considering derating for ambient temperature, grouping and cable length. If the application is a high-speed application, larger gauges or special stranding could be required to reduce heating.
Feedback, Communication and Brake Circuits
Indicate twisted pairs, correct conductor count and shielding of encoder signals. Have brake power and thermal sensors. Always check the exact requirement with your servo drive and motor documentation.
Stage 3 – Shielding, EMC and Noise Environment
Assess the EMC Environment
Look for sources of interference, including VFDs, contactors, welding equipment and running parallel power lines from the outset of layout. The power delivery and sensitive feedback signals are protected by a strong EMC strategy.
Decide Shielding Level and Style
Choose single or double shield (foil + braid) depending on noise level. In demanding situations, the individually shielded pairs on feedback lines deliver better EMI/RFI protection for industrial automation applications.
Routing and Grounding Strategy
Install route servo cables away from HV lines, keep length of runs short as practicable, and adhere to OEM recommendations for shield termination and grounding. Good practices greatly minimize noise problems in prototypes and production machines.
Stage 4 – Mechanical Duty: Flexing, Torsion and Bend Radius
Static vs Continuous Flex vs Torsion
Determine if the cable is in static, occasional flex, continuous drag chain or torsion mode for each cable run. Hulk Electric’s robot & torsion cables perform especially well in multi-axis applications, and our high flexible cables are designed specifically for linear drag chain applications.
Minimum Bend Radius and Power Chain Data
Check the static and dynamic bend radius of datasheet against your cable carrier design. Record travel distance, cycle rate, speed and acceleration, all of which directly affect the life of the cable.
Flex Life Expectations
Be sure to find cables that are rated for a particular number of cycles and under certain test conditions. Take your machine’s anticipated duty cycle and see if it matches these ratings, so it can be reliable over many years.
Stage 5 – Environmental Conditions: Oil, Coolant, UV and Chemicals
Temperature, Moisture and Hazards
Specify operating temperature range including from motors and ambient temperature. Choose jackets that are flexible throughout the entire temperature spectrum, and will not crack or become soft.
Oil, Coolant and Chemical Exposure
Use oil resistant and chemical resistant polyurethane or special jackets in environments where the product is used for machining or food processing. The halogen free and high temp models are equally reliable when exposed to harsh cleaners and industrial fluids.
Outdoor and UV Conditions
When installed outdoors, it is best to use UV-stabilised compounds to ensure that the jacket won’t degrade over time.
Stage 6 – Standards, Certifications and Compliance
Regulatory and Market Requirements
Make sure that cables comply with UL/cUL, CE, RoHS and industry standards such as NFPA 79. Often times, multiple certifications are required in global markets – Hulk Electric has a large portfolio of UL, CE, TÜV and other approvals for international deployment.
OEM System Compatibility
Always check against servodrive and motor manufacturer’s recommendations for maximum cable lengths for feedback circuits.
Stage 7 – Prototype Build: Assembly, Routing and Verification
Cable Termination and Connectors
Concentrate on quality crimping, strain relief and few connection points. signal integrity and mechanical durability are maintained when the termination is done properly.
Routing and Separation in Panels and Frames
Hold correct separation, bend radiuses and secure mounting in cable tracks. As an early prototype of a product, it creates problems with routing that can be solved before going into series production.
Prototype Verification Checks
Test electrical performance, mechanical integrity, temperature rise and absence of alarms for compliance against all checklist items. Collect information to help finalize specifications.
This step-by-step checklist provides OEM teams with the confidence to select servo cables from concept to reliable first prototype. You minimize risk and speed up development by tackling electrical, mechanical, environmental and compliance factors at an early stage.
Our servo & motor cables, high flexible drag chain cables and custom robot torsion solutions are all designed to address the most challenging automation needs and are manufactured in our 15,000㎡ facility. Our 20+ years of experience, full traceability and wide range of certifications enable us to support you in your new machine designs with quickest sampling times possible and tailored solutions. Talk to our engineering team about your project requirements and we will help you determine the best cables for your long lasting project.