What API Capacitors does

API Capacitors Ltd is a privately-held UK designer and manufacturer of bespoke power film capacitors, headquartered in a 22,000 sq ft facility at Leyden Works, Station Road, Great Yarmouth, Norfolk. Established in the 1980s and acquired in October 2012 from KPMG administration as part of the API Holdings group (sister companies include API Engineering Ltd, PPI Engineering Ltd and API Stone Ltd), the company operates a build-to-order model across seven core product lines: DC Capacitors, AC Capacitors, Snubber Capacitors, Energy Capacitors, Track Circuit Capacitors, IGBT Filter Capacitors and Custom Design Capacitors. Core technology centres on metallised polypropylene dielectric film with controlled self-healing capability, supported by film/foil designs in both dry and oil-filled constructions, precision winding machines, vacuum impregnation, an automated robotic endspray facility, ANSYS Workbench FEA, CAD/CAE using Creo, and an in-house 200kV High Voltage testing laboratory with partial discharge measurement capability.

API Capacitors serves safety-critical and reliability-critical power-electronics applications across rail traction, marine propulsion (including Royal Navy warships and merchant vessels), industrial medium-voltage variable frequency drives, HVDC grid and transmission, avionics, automotive and motorsport (Formula 1 via Mercedes HPC), and pulsed-power / plasma research deployments at CERN and the ISIS facility at the Rutherford Appleton Laboratory. Notable reference installations include Eurostar, London Underground (Central Line overhaul), the Royal Navy's HMS Queen Elizabeth and HMS Prince of Wales aircraft carriers, Mexico City Metro (STC), and the Hong Kong MTR battery-electric locomotives.

The revenue model is project-based custom engineering: each capacitor is quote-priced against customer specifications, volume discounts are available on estimated annual quantities, and lead times are stated at 6–8 weeks. Distribution is direct from the UK headquarters via a technical sales team supported by an overseas partner network. Revenue is not publicly disclosed. Competitive positioning is anchored in IRIS (International Rail Industry Standard) certification, ISO 9001 quality management (held 10+ years) and Cyber Essentials Plus, alongside proprietary self-healing metallised film technology and bespoke reverse-engineering capability for obsolete component replacement.

Name

API Capacitors

Legal name

API Capacitors Ltd

Website

https://api-capacitors.com

Company type

Private

Founded year

1980

Operating status

Operating

Headcount range

11–50 employees

Short description

API Capacitors Ltd is a UK designer and manufacturer of bespoke power film capacitors for safety-critical applications in rail traction, marine propulsion, industrial drives, defense, HVDC transmission and pulsed-power research, serving blue-chip OEMs and operators worldwide from its Great Yarmouth facility.

Ownership category

akta.pro rank

Product category

Power Capacitors for Power Electronic Applications

NAICS

Capacitor, Resistor, Coil, Transformer, and Other Inductor Manufacturing (334416)

SIC

Electrical Industrial Apparatus (3620)

akta.pro primary industry

Capacitors (Ceramic/Film/Electrolytic/Tantalum/Supercapacitors) (HDAHANAB)

Keywords

• Custom power capacitors
• Metallised film capacitors
• Rail traction capacitors
• Snubber capacitors
• Energy storage capacitors

Headquarters

HQ city

Great Yarmouth

HQ country

United Kingdom

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

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

Revenue model

1. Custom Power Capacitor Sales: Design and manufacture of bespoke power capacitors for industrial and OEM applications. Products are sold as custom-engineered solutions with pricing quoted based on customer specifications. Revenue is generated from one-time project-based orders for new build equipment as well as replacement and obsolescence solutions. Volume discounts are mentioned as applicable for estimated annual quantities.

Pricing tiers

Go-to-market motion1 record

Distribution channels2 records

Marketing channels5 records

Core offering

API Capacitors is the UK's leading designer and manufacturer of custom high-quality power capacitors for power electronic applications. Operating on a build-to-order model from a 22,000 sq ft facility in Great Yarmouth, the company designs and produces DC, AC, snubber, energy storage, track circuit, IGBT filter, and bespoke custom capacitors using metallised polypropylene dielectric film with self-healing capability. Products serve rail traction, marine propulsion, industrial drives, grid and transmission systems, automotive and avionics, and pulsed power research applications for blue-chip industrial and OEM customers.

Product overview

API Capacitors is the UK's leading designer and manufacturer of high-quality power capacitors for power electronic applications. The product portfolio consists of seven core capacitor product lines: AC Capacitors, DC Capacitors, Snubber Capacitors, Energy Capacitors (energy storage/discharge), Track Circuit Capacitors, IGBT Filter Capacitors, and Custom Design Capacitors. The company operates on a build-to-order model, tailoring each product to customer specifications rather than offering standard catalog items. Products serve diverse sectors including rail traction, marine propulsion, industrial drives, power conditioning, avionics, automotive, pulsed power, plasma research, fusion, and HVDC transmission systems. The core offering is complemented by full engineering services including design, diagnostics, FMEA, reverse engineering for obsolescence management, and rapid prototyping.

Differentiator

Problem solved

Functional benefit

Products and services

• DC Capacitors Custom-designed DC capacitors for power electronic applications including DC-link, smoothing, suppression, harmonic filtering, and electrolytic replacement. Uses metallised polypropylene dielectric film with self-healing capability. Sold to industrial and OEM customers in rail, marine, drives, power transmission, and avionics sectors.
• AC Capacitors AC capacitors designed for static drives, non-static drives, power electronics, power transmission, and rail applications including line filters, signalling, and auxiliary circuits. Custom-engineered to application specifications.
• Snubber Capacitors Snubber capacitors for GTO, IGCT and thyristor devices. Designed for high current carrying capability using low resistance foil electrodes, available in oil-filled or dry leak-free configurations. Used in power electronic applications for rail, marine, and industrial drives.
• Energy Capacitors Energy storage capacitors for pulsed power, medical, defence, research, and industrial applications. Features controlled self-healing technology with oil-filled or dry resin-filled options for rapid discharge, welding energiser, magnetising equipment, pulse forming networks, radar, laser, defibrillator, X-ray equipment, lightning simulators, and plasma/physics research.
• Track Circuit Capacitors Low frequency AC adjustable and high frequency DC fixed capacitors for jointless track circuits used in track-side signalling equipment on railways. Features self-healing technology and hermetic sealing for reliable long-life operation in rail signalling environments.
• IGBT Filter Capacitors IGBT filter capacitors designed to smooth output voltage and reduce ripple current from IGBT inverters in variable frequency drives, servo systems, and industrial applications. Custom-engineered to specific application requirements.
• Custom Design Capacitors

Quantifiable outcome

• Lead times reduced to 6-8 weeks at competitive prices following investment programme that doubled production capacity
• +2 more outcomes

Named customers9 records

Segments6 records

Ideal customer profiles6 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature8 records

Partnerships

Four partnerships are on record, tiered minor and core.

• Performance Plus PartnershipminorImplementation/ SI/ Consulting Partner · 11 January 2016Consultants who supported the evolution and development of the quality management system to the IRIS requirement level. Laurence Brooks, Managing Director of Performance Plus Partnership, stated the IRIS framework was greatly aided by sound basic processes already in operation.
• API Engineering LtdcoreOthersAPI Engineering Ltd is a sister company within the API Holdings group, supplying steel mill and mining equipment. Both companies share the same parent ownership and appear at joint events such as Offshore Europe 2015 on stand 5B60.
• PPI Engineering LtdcoreOthersPPI Engineering Ltd is a sister company within the API Holdings group, specialising in motor and generator design and manufacture. Both companies share the same parent ownership and appear at joint events such as Offshore Europe 2015.
• API Stone LtdminorOthersAPI Stone Ltd is a sister company within the API Holdings group, supplying bespoke stonework cladding for buildings. Both companies share the same parent ownership.

Scale indicators5 records

Recent moves6 records

Expansion highlights5 records

Broad incumbents

• ABB: ABB manufactures power capacitors and reactive power compensation equipment for industrial drives, rail traction, and HVDC transmission. Overlaps with API in rail and industrial drives capacitor applications and is one of the global incumbents API competes against.
• Schneider Electric: Schneider Electric manufactures power factor correction capacitors and medium-voltage drive capacitor products serving rail, marine, and industrial customers. Comparable industrial drives and grid applications customer base.
• Vishay Intertechnology: Vishay manufactures a broad line of passive components including DC-link, AC, and snubber film capacitors targeted at industrial, rail, and renewable energy applications. Comparable product overlap with API's core capacitor lines.
• KEMET (Yageo): KEMET, now part of Yageo, produces film, paper, and electrolytic capacitors including power film capacitors for industrial and traction applications. Competes directly in the metallised polypropylene film capacitor space.
• AVX (Kyocera): AVX manufactures film and supercapacitors including IGBT snubber and DC-link types used in automotive and industrial power electronics. Overlaps with API's IGBT filter and snubber capacitor lines.
• Siemens: Siemens Mobility supplies rail propulsion systems and associated power electronics, including capacitor components, and is named by API as a tier-1 rail customer. Direct competitor in rail traction capacitor content globally.
• TDK (EPCOS): TDK's EPCOS division manufactures metallised film and power capacitors for industrial, automotive, and renewable energy applications. Directly comparable product portfolio to API in AC/DC, snubber, and IGBT filter capacitors, but at vastly larger scale and broader catalogue.
• GE Vernova / Grid Solutions: GE Vernova supplies power electronics and grid components including HVDC capacitor banks. Named by API as a tier-1 rail OEM customer and a competitor for capacitor content in grid/transmission and rail applications.

Direct peers

• WIMA: German specialist manufacturer of custom and standard metallised film capacitors for industrial, power electronics, and audio applications. Closest like-for-like peer in film capacitor technology and custom-engineered approach.
• ICAR (Industrie Capari): ICAR is an Italian specialist in power capacitors for industrial, traction, and renewable applications, with self-healing metallised film technology. Closely comparable in technology, end-markets (rail, drives), and custom engineering focus.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks6 records

Key highlights7 records

Customer concentration

• Xx.com/API_Capacitors
• Facebookfacebook.com/apicapacitorsltd
• LinkedInlinkedin.com/company/api-capacitors

Compliance3 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles4 records

Funding overview

Funding rounds1 record

Investors1 record

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 API Capacitors