What Custom Coils does

Custom Coils is a privately held US manufacturer of custom magnetic components, founded in 1967 and headquartered in Alcester, South Dakota, where all products are wound, vacuum-pressure-impregnated, assembled, and tested in-house. The company designs and produces transformers and inductors up to approximately 2 kVA using VPI dry-type construction, with a catalog spanning high-voltage, switchmode, flyback, toroidal, pulse, isolation, control, inverter, ferrite, and surface-mount variants, as well as DC igniters, antennas, air coils, and hydrogen coils. Sales are conducted on a quote-based, custom-specification model with engineer-to-engineer technical engagement, supported by Request-for-Quote functionality on the company website and a 4-8 week lead time on prototype and low-volume runs.

The company serves OEM customers across multiple verticals. Primary focus areas include electric vehicle power electronics (gate drive, pulse, flyback, and isolation magnetics for SiC and GaN switching), renewable energy systems (solar, wind, and battery energy storage inverters and BMS), semiconductor manufacturing equipment (plasma tools, RF generators, high-density PCB assembly), and robotics and industrial automation (control transformers, solenoid coils, drive transformers). Secondary verticals include aerospace and military, oil and gas downhole applications, and biomedical devices. The customer base spans 1000+ equipment manufacturers worldwide, according to company materials, with ISO 9001:2015 certification supporting OEM qualification.

Revenue is generated through one-time hardware sales of custom magnetic components, with engineering design services bundled into each engagement. Pricing is determined per RFQ rather than via published tiers; the company is privately held with no institutional funding, no acquisitions, and no disclosed partnerships, operating as a single-site specialty shop in the United States with no overseas manufacturing or hand-offs.

Name

Custom Coils

Legal name

Custom Coils

Website

https://customcoils.com

Company type

Private

Founded year

1967

Operating status

Operating

Headcount range

101–250 employees

Short description

Custom Coils designs and manufactures custom transformers, inductors, and magnetic components for OEM customers in EV power electronics, renewable energy, semiconductor equipment, industrial automation, aerospace, and biomedical applications from its Alcester, South Dakota facility since 1967.

Ownership category

akta.pro rank

Headquarters

HQ city

Alcester

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Personnel, Operations, Supply Chain, Technology or R&D, Infrastructure, Marketing or Sales

Revenue model

1. Custom Transformers Manufacturing: Design and manufacture of custom magnetic components including transformers, inductors, and coils. Products are custom designed and built to client specifications with VPI dry-type construction. Revenue generated through one-time hardware sales with engineering services bundled into product development.
2. Custom Design Services: End-to-end custom design services including design review, prototyping, testing and quality inspection. Services provided as part of product engagement - LCR meters testing for inductance, impedance, capacitance and self-resonance frequency. Products can be made RoHS and REACH compliant.
3. Standard Product Catalog: Catalog of standard transformer and inductor product lines including high voltage transformers, switchmode transformers, flyback transformers, toroidal transformers, power inductors, and specialty magnetics.

Pricing tiers

Go-to-market motion2 records

Distribution channels1 record

Marketing channels5 records

Core offering

Custom Coils designs and manufactures custom transformers, inductors, and magnetic components for commercial and industrial OEMs, using VPI (Vacuum Pressure Impregnation) dry-type specialty processes with output up to approximately 2 kVA. The company offers an end-to-end custom manufacturing service covering design review, prototyping, winding, impregnation, assembly, electrical testing, and quality inspection, alongside a catalog of standard product families such as high voltage, switchmode, flyback, toroidal, pulse, isolation, control, and inverter transformers, plus toroidal, air core, ferrite, power, and surface mount inductors. Products are quote-based and engineered against real customer waveforms and operating environments for applications including EV power electronics, renewable energy, semiconductor equipment, robotics, aerospace, oil and gas downhole, and biomedical devices.

Product overview

Custom Coils is a custom transformer, inductor, and coil manufacturer established in 1967, headquartered in Alcester, South Dakota. The company offers a comprehensive portfolio of magnetic components including High Voltage Transformers, Switchmode Transformers, Flyback Transformers, Trigger Pulse Transformers, Step Up/Down Transformers, Power Transformers, Toroidal Transformers, Antennas and Air Coils, DC Igniters, various Inductor types (High Current, Toroidal, Air Core, Ferrite, Power, Surface Mount), Control Transformers, Inverter Transformers, Low Profile Transformers, Ferrite Transformers, Pulse Transformers, Single Phase Transformers, Specialty Transformers, Isolation Transformers, Surface Mount Transformers, Hydrogen Coils, and Down Hole Applications. The company also provides end-to-end Custom Manufacturing services encompassing design review, prototyping, testing, and quality inspection. Their products serve diverse industries including automotive/EV, aerospace, military, biomedical, semiconductor manufacturing, power distribution, mining, oil exploration, seismic exploration, renewable energy, robotics, and industrial automation. Custom Coils operates as a VPI dry-type specialty shop with transformers up to approximately 2 kVA.

Differentiator

Problem solved

Functional benefit

Products and services

• High Voltage Transformers Transformers designed to handle high voltage applications, used in plasma generation, industrial cutting lasers, and other demanding high-voltage applications for industrial OEMs.
• Switchmode Transformers Transformers for switch-mode power supply applications that enable efficient AC/DC power conversion and voltage regulation at high frequencies for commercial and industrial electronics OEMs.
• Flyback Transformers High voltage and mid-to-high frequency transformers used in switch-mode power supplies and CRT monitor applications, capable of generating voltages from 10 to 35 kV.
• Trigger Pulse Transformers High voltage trigger transformers that generate high voltage spikes for ionizing gas in laser systems, flash tubes, spark gaps, and stun guns for industrial and specialty equipment OEMs.
• Step Up/Down Transformers Transformers that increase or decrease AC voltage levels, supporting 110V to 220V and 220V to 110V conversions for various industrial applications.
• Power Transformers Transformers for power conversion and distribution applications in industrial settings, supporting AC/DC power conversion and energy conservation for industrial OEMs.
• Toroidal Transformers Ring-shaped transformers with circular coil windings that generate inductance and capacitance, providing low stray flux and high efficiency for biomedical, industrial, and aerospace applications.
• Antennas and Air Coils Coiled antenna designs used as inductors and wireless antennas in electronic circuits, including solenoid coils for self-resonance and self-capacitance applications for electronics OEMs.
• Down Hole Application Magnetics Specialized magnetic components for oil exploration and downhole drilling applications, designed to withstand harsh environmental conditions for oil and gas OEMs.
• DC Igniters 12V DC igniters with thermoplastic shell encapsulated in two-part epoxy that convert DC voltage to high voltage sparks (20-26 kV output, ignition times less than 10 microseconds) for igniting fuel in burners, pressure washers, tar kettles, and industrial heating equipment.
• High Current Inductors Inductors designed to handle high current applications, used in power electronics and filtering applications for power electronics OEMs.
• Custom Transformer and Inductor Manufacturing Services End-to-end custom design services including design review, prototyping, winding, VPI impregnation, assembly, electrical testing (LCR meters for inductance, impedance, capacitance, self-resonance), quality inspection, and manufacturing of specialized transformers and inductors to meet specific customer requirements, with optional RoHS and REACH compliance.
• Hydrogen Coils Magnetic coils specifically designed for hydrogen-related applications and fuel systems for clean energy and industrial OEMs.
• Control Transformers Transformers for industrial control applications, providing voltage step-down for PLCs, automation controllers, and machine control circuits with inrush headroom for contactor banks, targeting automation OEMs and machine builders.
• Inverter Transformers Transformers for inverter and renewable energy applications, supporting gate drive, sense, and control power functions in EV and solar/wind systems for EV and renewable energy OEMs.
• Low Profile (LPC) Transformers Compact transformers with reduced height for tight enclosures in robotics and compact robotic chassis applications, targeting robotics and automation OEMs.
• Ferrite Transformers Transformers with ferrite cores operating at 20 kHz to 1+ MHz frequencies, designed for high-frequency power conversion applications in semiconductor equipment and other high-frequency electronics.
• Pulse Transformers Transformers for pulse applications including gate drive circuits in EV inverters, coupling gate signals across high voltage barriers with high common-mode transient immunity, for EV power electronics OEMs.
• Single Phase Transformers Single-phase transformers based on Faraday's law of electromagnetic induction for stepping up or stepping down voltage in various commercial and industrial applications.
• Specialty Transformers Custom specialty transformers designed for unique and demanding industrial applications beyond standard transformer categories, targeting industrial OEMs with non-standard requirements.
• Isolation Transformers Transformers providing galvanic isolation between high voltage and low voltage circuits, protecting electronics from faults and decoupling common-mode noise, for BMS cell-monitoring, sensor isolation, and HV-LV boundary applications.
• Surface Mount Transformers Surface mount transformers for PCB assembly, compatible with pick-and-place manufacturing processes for high-density electronics and semiconductor OEMs.
• Toroidal Inductors Inductors with toroidal core construction, providing low stray field and high efficiency for filtering and energy storage applications for power electronics and industrial OEMs.
• Air Core Inductors Inductors without a magnetic core, used in high-frequency applications where magnetic saturation must be avoided, for RF and high-frequency electronics OEMs.
• Ferrite Inductors Inductors wound on ferrite cores for high-frequency applications, offering low eddy current losses compared to laminated steel cores, for power electronics and semiconductor OEMs.
• Power Inductors Inductors for power electronics applications including OBC, DC-DC converters, and filter stages, designed against actual current waveforms and thermal environments, for EV and renewable energy OEMs.
• Surface Mount Inductors Surface mount inductors (SMD) operating from 100 kHz to 1+ MHz, designed for high-density PCB assembly in semiconductor equipment and electronics manufacturing applications.

Quantifiable outcome

• 50+ years of industry experience since 1967
• +2 more outcomes

Named customers7 records

Segments7 records

Ideal customer profiles6 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature5 records

Scale indicators4 records

Recent moves6 records

Expansion highlights4 records

Direct peers

• Hammond Manufacturing: Hammond Manufacturing is a long‑established North American manufacturer of custom and standard transformers, inductors, chokes and magnetic components serving industrial, electronic and electrical equipment OEMs — direct overlap with Custom Coils' custom magnetics offering.
• Coilcraft: Coilcraft designs and manufactures RF, power and signal inductors, transformers and chokes for automotive, industrial, semiconductor and communications customers; competes head‑to‑head with Custom Coils in custom magnetics for EV and semiconductor applications.
• Triad Magnetics: Triad Magnetics produces custom and standard transformers, inductors and chokes with VPI/encapsulated construction for industrial, medical, audio and OEM customers — directly comparable product portfolio and custom‑engineered go‑to‑market.
• Signal Transformer (Bel Fuse): Signal Transformer, a Bel Fuse brand, manufactures transformers, inductors and magnetics for industrial, telecom and power conversion OEMs — overlapping with Custom Coils in switchmode, isolation and power magnetics for industrial OEM customers.
• Bourns, Inc. Bourns manufactures custom and standard magnetics (transformers, inductors, chokes) alongside circuit protection, sensing and resistive products for automotive, industrial, telecom and EV — comparable customer mix and custom magnetics focus.
• Premier Magnetics: Premier Magnetics designs and manufactures custom transformers, inductors, chokes and coils for OEM customers in industrial, medical, telecom and renewable markets — directly comparable custom magnetics scope, customer mix and engineering‑driven sales model.

Broad incumbents

• Würth Elektronik: Würth Elektronik is a large global passive‑component manufacturer with extensive transformer, inductor and choke portfolios serving industrial, automotive and renewable customers — broader catalog and global footprint than Custom Coils but overlapping product/customer space.
• TDK Corporation: TDK (including EPCOS) is a global magnetics and electronic components giant producing power, signal and RF transformers and inductors for automotive, industrial, renewable and semiconductor OEMs — competes with Custom Coils in EV and renewable inverter magnetics but offers much wider catalog.
• Vishay Intertechnology: Vishay manufactures a broad portfolio of passive components including transformers, inductors, magnetics and filter components used by industrial, automotive and military customers — comparable magnetics offerings but part of a much larger discrete‑component portfolio.
• Eaton: Eaton is a major power management and industrial electrical equipment manufacturer with custom transformers, coils and magnetics in its Electrical Americas segment — overlaps with Custom Coils' industrial, renewable and aerospace/military custom magnetics work as part of a much broader product portfolio.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks6 records

Key highlights7 records

Customer concentration

• LinkedInlinkedin.com/company/custom-coils
• Pinterestpinterest.com/customcoils
• Xx.com/CustomCoils
• Facebookfacebook.com/CustomCoilsInc

Compliance3 records

Revenue estimate

Valuation estimate

Number of profiles

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Custom Coils