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HQ: Salisbury, Maryland
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Toroid Corporation
Specialty Magnetics • 100% Custom Engineering

Custom Inductors & Chokes

Engineered precisely around your operating conditions, thermal limits, and saturation requirements. Unlike manufacturers offering only standard off-the-shelf components, Toroid Corporation develops 100% custom-tailored solutions.

No Fixed Catalog LimitationsClass B, F & H InsulationPrototype to Scaled OEM

Toroid Corporation

Custom Inductor Design

Active CAD
+ CAD SPEC · TOROIDAL
EFF · 98.4%
DC BIAS · OPTIMIZED
LEAKAGE · <1.2%
Toroid Corporation Custom Toroidal Inductor
Inductance
10µH–500mH
Current
Up to 150A
Frequency
50Hz–500kHz
Insulation
Class B/F/H

Engineered to Your Specs:

Target InductanceContinuous & Peak CurrentDC BiasOperating FrequencyClass B, F & HMounting & Envelope
Engineering Review Criteria

Custom Design Considerations

Our engineering team evaluates the following requirements when developing a custom inductor tailored to your application:

Inductance & Tolerance

Target nominal inductance values and strictly maintained tolerance thresholds across varying operational frequencies.

Current & DC Bias

Continuous rated current, peak surge handling, and DC bias magnetization to prevent magnetic saturation under maximum load.

Frequency & Ripple

Optimized for your specific operating frequency and expected AC ripple current to eliminate audible noise and excess core heat.

Core Selection & Materials

Magnetic materials (iron powder, sendust, ferrite, nanocrystalline, or high-grade electrical steel) selected strictly for application efficiency.

Thermal Performance

Engineered operating temperatures, convection vs. forced-air cooling, and insulation systems rated for Class B (130°C), Class F (150°C), or Class H (180°C).

Physical Configuration

Custom envelope dimensions, PCB pin layouts, flying leads, center-hole potted encapsulation, or custom vertical mounting brackets.

Electrical Performance & Losses

Minimized DC resistance (DCR), controlled AC resistance, low winding capacitance, and tightly targeted copper vs. core loss tradeoffs.

Toroid Proprietary Software & Testing

40+ Years of Precision Magnetic Design

Our experienced design group uses sophisticated software programs refined over 20+ years to calculate the optimal and conservative solution for your custom inductor and transformer needs. This eliminates the “human factor” and trial-and-error, ensuring your prototype meets specifications the first time around.

Efficiency Curves
Optimal Core Utilization

Efficiency Curves

Toroidal core geometry eliminates air gaps in the magnetic path, resulting in virtually zero leakage flux and significantly higher efficiency across nominal load levels.

Thermal Time Constant
Duty Cycle Considerations

Thermal Time Constant

A more compact inductor can be engineered when the duty cycle is intermittent and shorter than the thermal time constant of the unit, saving volume and weight.

Operating Temperature Rise
Safety & Class Ratings

Operating Temperature Rise

Operating temperature is calculated precisely based on mounting and cooling conditions. Units can be built to UL recognized standards for Class B, E, F, or H.

Voltage Drop Characteristics
Full Load Regulation

Voltage Drop Characteristics

Predictable voltage drop characteristics with minimal harmonic distortion across 50/60 Hz and high-frequency operating conditions.

Winding Configurations
Single & Dual Primaries

Winding Configurations

Multi-winding arrangements allow series or parallel configurations, custom differential inductances, and balanced multi-rail filtering.

Rectifier Filter Inductors
DC Power Supply Integration

Rectifier Filter Inductors

Our design software accurately calculates ripple suppression and DC bias tolerances specifically for full-wave and bridge rectifier filtering circuits.

Field Proven Solutions

Custom Inductor & Choke Applications

Custom inductors and chokes may be designed for applications including:

Power Supplies & Power Conversion

High-efficiency filter inductors, boost/buck PFC chokes, and energy storage chokes for SMPS and DC-DC converters.

Industrial Equipment & Controls

Rugged magnetic chokes engineered for motor drives, robotics, automation systems, and variable frequency drives (VFDs).

Electrical Noise Filtering

Common-mode and differential-mode toroidal filtering inductors for critical EMI/RFI suppression in sensitive electronics.

Renewable Energy & Power Systems

Grid-tie solar inverters, battery storage conversion, wind generators, and power factor correction magnetics.

Medical & Electronic Equipment

Low-leakage, high-dielectric inductors designed for medical diagnostics, surgical instrumentation, and laboratory devices.

Specialized OEM Applications

Custom-configured inductors built to proprietary OEM mechanical and electrical blueprints with guaranteed repeatability.

Talk to Engineering

Talk to a magnetics designer. Not a sales rep.

Whether you need custom toroidal inductors, common-mode chokes, or high-frequency filter assemblies, our engineering team reviews your specifications directly. Detailed design proposals typically turn around within 48 hours.