Custom Inductors & Chokes
KATOY designs and manufactures custom inductors and chokes for power electronics, EMI filtering, industrial power supplies, automation equipment and specialized OEM applications. Product designs can be developed according to required inductance, current, operating frequency, magnetic core, winding, insulation, DCR, thermal, dimensional and mounting requirements.
Magnetic Design Based on Current, Frequency and Circuit Function
An inductor stores energy in its magnetic field when current flows through the winding. In practical power-electronic circuits, the required component cannot be defined by inductance alone. Rated current, peak current, operating frequency, DC resistance, core material, air gap, winding structure, core losses, copper losses and temperature rise can all affect the final design.
The term choke generally refers to an inductor used to impede unwanted AC or high-frequency current while allowing the desired current component to pass. Common-mode chokes, power chokes and other inductive components therefore differ in magnetic circuit and winding arrangement according to their intended electrical function.
KATOY develops custom inductors and chokes from customer electrical specifications, drawings, existing component information or reference samples. Magnetic and mechanical requirements are evaluated together before the final structure is defined.
- Inductance: specified together with the relevant test frequency, current or operating condition where required.
- Rated and peak current: used to evaluate winding temperature, conductor sizing and magnetic operating point.
- Saturation behavior: core material, geometry and air gap determine how inductance behaves as current increases.
- DCR: DC resistance affects copper loss, voltage drop and thermal performance.
- Operating frequency: influences core loss, winding loss and selection of magnetic material and construction.
- Core and winding structure: selected according to energy storage, filtering, current, loss, dimensional and installation requirements.
Inductor and Choke Constructions
KATOY manufactures inductors and chokes in a broad range of magnetic-core, winding, current and mounting configurations. The products shown below illustrate representative custom constructions rather than fixed catalog models.
Common-Mode Choke vs. Differential-Mode Inductor
These components are both used in filtering circuits, but they act on different current components and therefore use different magnetic and winding principles.
| Design Factor | Common-Mode Choke | Differential-Mode Inductor |
|---|---|---|
| Main Function | Attenuates noise currents flowing in the same direction on two or more conductors relative to the reference or ground. | Provides inductive impedance to differential current ripple or noise in the normal current path. |
| Winding Arrangement | Typically uses two or more coupled windings on a common magnetic core. | Commonly uses a single current-path winding or another circuit-specific inductive arrangement. |
| Magnetic Flux | Under ideal differential load current, opposing flux produced by paired windings largely cancels in the core. | Load current contributes directly to the magnetic operating point and must be considered in saturation design. |
| Key Design Parameters | Common-mode impedance, leakage inductance, current, winding balance, insulation and frequency range. | Inductance, rated and peak current, saturation, DCR, ripple current, losses and temperature rise. |
| Typical Engineering Use | Common-mode EMI suppression in power or signal lines. | Differential filtering, ripple reduction or energy storage depending on the circuit. |
Information Required for Custom Inductor and Choke Development
Accurate current, frequency and magnetic operating data are important because inductance, saturation, winding loss, core loss and temperature are interdependent.
Custom Inductors and Chokes for Power Electronics and Industrial Equipment
KATOY develops inductive magnetic components for OEM equipment where filtering, current smoothing, energy storage or EMI-control functions require project-specific magnetic design.
Custom Magnetic Design from Requirement Review to Production
As a custom inductor and choke manufacturer, KATOY supports OEM projects from electrical and magnetic requirement review through core selection, winding design, prototype manufacturing, sample validation and recurring production.
Verification According to Inductor and Choke Specifications
Inductor and choke testing should correspond to the electrical and magnetic parameters defined for the product. Measurement conditions are important because inductance and impedance can depend on frequency, current and test method.
KATOY applies product-specific inspection and manufacturing controls according to approved specifications rather than using one universal test condition for all magnetic components.
- Inductance and electrical parameter verification
- DCR measurement where specified
- Winding and connection inspection
- Insulation-related testing as required by the product specification
- Visual and dimensional inspection
- Production process and quality control
Custom Inductor and Choke Questions
Common engineering and sourcing questions about inductance, current, common-mode filtering, magnetic cores and custom manufacturing.
What information is needed to design a custom power inductor?
Useful information includes target inductance, rated current, peak or saturation current, operating frequency, ripple waveform, DCR requirement, allowable temperature rise, dimensions, mounting method and application information. Drawings or reference samples can also support evaluation.
What is the difference between a common-mode choke and a differential-mode inductor?
A common-mode choke uses coupled windings to impede common-mode noise while allowing the intended differential current to pass. A differential-mode inductor is in the normal current path and provides inductive impedance to differential ripple or noise. Their magnetic operating conditions are therefore different.
Why are rated current and saturation current different?
Rated current is generally associated with allowable thermal performance under continuous operation, while saturation current relates to the change in magnetic behavior and inductance as core flux density increases. The applicable definition and test condition should be stated in the product specification.
Why is DCR important in a power inductor?
DCR is the DC resistance of the winding. It contributes to copper loss and voltage drop, and therefore affects thermal performance and circuit efficiency. Lower DCR normally requires consideration of conductor size, winding structure and available component dimensions.
What is the purpose of an air gap in an inductor core?
A controlled air gap can reduce the effective permeability of the magnetic circuit and increase its ability to support DC magnetizing current without excessive inductance reduction. Gap size is therefore part of the magnetic design rather than a general feature required for every inductor.
Can KATOY manufacture common-mode chokes for three-phase systems?
Yes. KATOY manufactures multi-winding common-mode choke structures, including three-phase constructions, according to the required current, filtering, insulation and mechanical specifications.
Can KATOY manufacture inductors from customer drawings or samples?
Yes. Custom inductors and chokes can be evaluated from electrical specifications, drawings, existing component information or reference samples. Additional circuit and operating data may be required before prototype development.
Can KATOY support prototype and recurring production?
Yes. KATOY supports custom magnetic-component projects from requirement review and prototype development through sample validation and recurring manufacturing.
Need a Custom Inductor or Choke?
Send your inductance, current, operating frequency, DCR, saturation, waveform, temperature, dimensions, winding and mounting requirements for engineering evaluation and quotation.