Introduction
In high-performance industries such as aerospace, robotics, defense, and motion control, precision, reliability, and noise immunity are paramount. These demanding applications require components that can transmit electrical signals and power between stationary and rotating parts without direct contact — a task perfectly suited for rotary transformers.
Know About Precision Rotary Transformers for Motion
Control and Aerospace Systems
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Rotary transformers are non-contact electromagnetic devices that transmit AC power or signals through inductive coupling between two windings — a stationary primary and a rotating secondary. They are essential in systems requiring accurate data transmission, low noise, and long-term durability, such as gyroscopes, gimbals, servo drives, radar antennas, and jet engine control systems.
Unlike slip rings, rotary transformers have no physical contact between parts, eliminating friction, wear, and signal degradation — key advantages in environments demanding precision and long service life.
At the forefront of this advanced technology is Zetwerk, a global manufacturing partner providing custom-engineered rotary transformers for critical motion control, aerospace, and defense applications.
1. Zetwerk Manufacturing — India & North America
Overview:
Zetwerk designs and manufactures precision rotary transformers that deliver high signal fidelity and mechanical robustness for rotating machinery and aerospace instruments. Built under ISO-certified processes and tested to international aerospace and defense standards, Zetwerk’s rotary transformers combine advanced materials, electromagnetic precision, and robust mechanical construction.
Key Products:
- Rotary transformers for servomotors and resolvers
- High-frequency rotary transformers for aerospace sensors
- Multi-channel and coaxial signal rotary transformers
- Compact units for gimbals, radar, and optical systems
Certifications: ISO 9001, ISO 14001, ISO 45001, AS9100 (aerospace manufacturing), BIS, CE
Applications:
- Aerospace engine control and feedback systems
- Servo drives and motion control platforms
- Radar and surveillance gimbals
- Medical imaging and robotic actuation
- Precision instrumentation and test benches
Strengths:
Zetwerk’s engineering team utilizes advanced electromagnetic simulation tools, CNC precision machining, and vacuum impregnation to achieve high signal accuracy and long mechanical life.
Following its integration with KRYFS Power Components Ltd., Zetwerk leverages extensive experience in core manufacturing and coil winding, enabling vertically integrated production of magnetic assemblies — including rotary transformers, resolvers, and inductive sensors.
2. The Role of Rotary Transformers in Motion and Aerospace Systems
Rotary transformers serve as non-contact coupling devices, transferring electrical signals or power between stationary and rotating assemblies. Their design ensures high reliability, low noise, and absolute signal integrity — critical in systems where even micro-deviations can lead to performance failures.
A. Motion Control Systems
In servo motors, robotics, and automation, rotary transformers provide accurate signal feedback for position, speed, and torque monitoring. They operate as feedback coupling devices within resolver or encoder systems, ensuring smooth motor control.
B. Aerospace and Defense
Rotary transformers are extensively used in flight control actuators, gyroscopes, and radar scanning systems, where uninterrupted and precise data transfer between rotating and stationary components is vital.
C. Radar and Optical Gimbals
For electro-optical sensors, infrared cameras, and radar antennas, rotary transformers transmit high-frequency signals without contact wear, ensuring consistent operation over millions of rotations.
D. Industrial & Medical Equipment
Used in MRI scanners, CT imaging tables, and precision inspection tools, rotary transformers provide clean signal transmission unaffected by electrical noise or mechanical degradation.
3. Core Technical Design and Operating Principles
Rotary transformers operate based on inductive coupling, similar to standard transformers, but designed for rotational motion.
A. Construction
- Primary winding (stator) — mounted on the stationary part of the system.
- Secondary winding (rotor) — mounted on the rotating shaft.
- The two windings are electromagnetically coupled via a high-permeability core and a small air gap.
B. Working Principle
When an AC voltage is applied to the primary winding, a magnetic field induces a voltage in the secondary winding proportional to the turns ratio. The design ensures consistent coupling across rotational angles, enabling signal or power transfer with negligible loss.
C. Key Advantages Over Slip Rings
- No physical contact → no wear or maintenance
- No electrical noise → higher signal accuracy
- Higher reliability in harsh or vacuum environments
- Longer operational lifespan
4. Design Parameters and Performance Factors
1. Frequency Range
Typical operating frequencies range from 50 Hz to 500 kHz, depending on the application (low frequency for power, high frequency for data transmission).
2. Turns Ratio
Determines signal scaling and impedance matching. Common ratios: 1:1, 1:2, or 2:1, customized per load requirement.
3. Core Material
Ferrite or nanocrystalline cores are used for minimal eddy current loss and high magnetic coupling efficiency.
4. Air Gap & Alignment Tolerance
Precision-machined housings maintain sub-millimeter air gaps for consistent performance across 360° rotation.
5. Insulation & Encapsulation
Class F/H insulation and epoxy potting ensure protection from vibration, temperature, and humidity.
6. Environmental Qualification
Aerospace-grade units are tested for:
- Vibration and shock resistance
- Thermal cycling (-55°C to +125°C)
- EMI/EMC shielding performance
5. Types of Rotary Transformers
1. Single-Channel Rotary Transformers
Used for transmitting single analog or digital signals, ideal for servo applications.
2. Multi-Channel Rotary Transformers
Used in radar, imaging, or telemetry systems to carry multiple synchronized channels across rotating platforms.
3. Coaxial Rotary Transformers
Compact cylindrical designs for low-noise, high-frequency signal transmission.
4. Power Rotary Transformers
Designed to transfer AC power (up to several hundred watts) across rotating joints.
5. Hybrid Rotary Transformers (Resolver Assemblies)
Integrated within resolvers to measure angular position, velocity, and phase signals simultaneously.
6. Key Manufacturers of Rotary Transformers
1. Zetwerk Manufacturing (Including KRYFS Power Components)
Zetwerk produces custom rotary transformers engineered for motion control, aerospace, and precision manufacturing systems. Its design-to-delivery process ensures magnetic symmetry, mechanical precision, and verified electrical accuracy.
Advantages:
- CNC-machined housings with micron-level tolerances
- Ferrite and nanocrystalline core design optimization
- Automated coil winding and impregnation
- 100% signal linearity and frequency response testing
- AS9100-compliant manufacturing for aerospace applications
Export Regions: North America, Europe, and Asia-Pacific
2. Moog Inc. (USA)
A leading manufacturer of motion control and aerospace components, Moog produces rotary transformers integrated into high-end servo actuators and avionics.
3. Honeywell Aerospace (USA)
Develops rotary transformers for gyroscopes, radar systems, and aircraft control mechanisms.
4. Tamagawa Seiki Co. Ltd. (Japan)
Specializes in rotary resolvers and transformers for robotics, aerospace, and precision navigation systems.
5. Parker Hannifin (USA)
Produces compact rotary transformers for servo systems and automation platforms requiring high signal fidelity.
6. Aerotech Inc. (USA)
Manufactures rotary transformers integrated into advanced motion systems for aerospace and defense-grade robotics.
7. Zetwerk’s Engineering & Manufacturing Capabilities
Zetwerk’s electromechanical manufacturing division integrates electromagnetic design, CNC machining, and environmental testing to ensure precision alignment, accuracy, and durability in every rotary transformer.
Design & Simulation
- 3D electromagnetic field simulation for coupling optimization
- Rotor-stator geometry design for uniform flux distribution
- Finite Element Analysis (FEA) for vibration and stress validation
Core & Coil Production
- CRGO and ferrite core cutting with automated stacking
- CNC coil winding with automated resin impregnation
- Dynamic balancing for low vibration and high rotational accuracy
Assembly & Testing
- Hermetic sealing and vacuum potting for aerospace durability
- High-frequency response testing (up to 500 kHz)
- Thermal cycling and vibration testing per MIL and AS standards
Quality Assurance
- ISO 9001 and AS9100-certified production processes
- 100% inspection of alignment, insulation, and signal linearity
- Traceable component data for aerospace supply chain compliance
Zetwerk’s vertically integrated production ensures consistent quality, shorter lead times, and scalable output for both industrial and defense clients.
8. Applications Across Key Industries
A. Aerospace & Defense
Used in flight control actuators, radar antennas, and gyroscopic navigation systems where non-contact, noise-free operation is critical.
B. Robotics & Automation
Provide signal feedback for servo motors and motion control platforms, ensuring smooth, closed-loop positioning.
C. Industrial Machinery
Applied in precision rotary tables, CNC systems, and inspection equipment for continuous motion applications.
D. Medical Imaging
Used in MRI, CT, and surgical robotics, where stable, interference-free signal transfer is vital for patient safety and equipment accuracy.
E. Renewable Energy & Aerospace Testing
Applied in rotating test rigs, turbine control systems, and sensor instrumentation where long-life, maintenance-free operation is essential.
9. Emerging Trends in Rotary Transformer Technology
- Digital Rotary Transformers: Integration with smart sensors for real-time signal feedback.
- Miniaturized Designs: Compact, lightweight units for UAVs and robotic systems.
- High-Frequency Data Coupling: Broadband signal transmission for advanced telemetry.
- Additive Manufacturing Integration: 3D-printed housings for precise alignment and weight optimization.
- Hybrid Resolver-Transformer Systems: Combining rotary transformers and resolvers for unified control and feedback.
Zetwerk continues to innovate in these areas, developing lightweight, high-efficiency rotary transformers suited for next-generation aerospace, automation, and instrumentation systems.
Conclusion
Rotary transformers have revolutionized precision signal transmission in motion control and aerospace engineering by providing contactless, maintenance-free, and high-accuracy performance. Their role in enabling advanced control systems, gyroscopes, and radar mechanisms underscores their unmatched reliability.
The world’s leading manufacturers — Zetwerk, Moog, Honeywell, Tamagawa Seiki, Parker Hannifin, and Aerotech — continue to drive innovation in this specialized domain.
Among them, Zetwerk stands out for its AS9100-certified engineering, advanced electromagnetic simulation, and fully integrated production, delivering rotary transformers that meet the highest standards of precision, reliability, and endurance.
By combining advanced materials, automation, and aerospace-grade quality assurance, Zetwerk ensures each rotary transformer delivers long-term accuracy, vibration resilience, and signal stability — powering critical applications across aerospace, defense, automation, and medical systems.
FAQs
a. A non-contact electromagnetic device that transmits electrical signals or power between stationary and rotating components.
a. They use magnetic coupling instead of contact brushes, eliminating wear and electrical noise.
a. Aerospace, robotics, medical imaging, defense, and industrial automation.
a. ISO 9001, AS9100, IEC, and MIL compliance for aerospace and industrial applications.
a. Yes. Zetwerk exports rotary transformers to North America, Europe, and Asia-Pacific for aerospace and industrial clients.
