Transformers & Rectifiers Ltd specialise in the design, and manufacture of custom-made power supplies for customer specific power applications.

Our range of products extended from simple wound components such as transformers, and chokes through to multiple units, controlled to provide an application specific power control solution.

Being a bespoke products manufacturer our catalogues, and website, could never practically demonstrate our total capabilities, so if there is an item, product, or system not mentioned please contact our Sales Office who will be pleased to discuss your requirements.

Transformers & Rectifiers Ltd are the largest power, in-house manufacturer of both transformers, and rectifiers, in the United Kingdom. In addition we are the sole UK manufacturer of Power Voltage Regulating Transformers.

Using a range of component building blocks Transformers & Rectifiers Ltd are able to offer an enormously wide range of diverse product. The Transformers & Rectifiers Ltd product range includes, but is not limited to the following products:

Power Transformers. Fluid filled. Includes Rectifier, Converter, Traction, and Distribution Transformers with throughput capacities up to 7.5 MVA, and highest system voltages up to 36 kV.

Power Transformers. Dry type. Non-encapsulated types employing the Du-Pont Nomex Aramid paper system with varnish envelopment. Includes Rectifier, Converter, Traction, and Distribution Transformers with throughput capacities up to 4 MVA, and highest system voltages up to 17.5 kV.

Available in both naturally ventilated, and sealed, up to IP65 for adverse site conditions type.

Power Cast Resin Encapsulated Transformers. Includes Rectifier, Converter, Traction, and Distribution Transformers with throughput capacities up to 5 MVA, and highest system voltages up to 24 kV.

Power Voltage Regulating Transformers. Fluid filled, with stand alone, continuously variable on-load capacities up to 1.25 MVA, or in conjunction with a fixed ratio transformer to allow some slight of hand connections that lifts capacity up to 2.5 MVA.

Air-cooled options are available at reduced capacities.

Power Voltage Regulating Transformer Units. Voltage Regulating Transformer Units combine fixed ratio transformers with voltage regulating transformer to achieve a variable AC output for any voltage from very low voltage up to the highest system voltage indicated above for transformer. Equally it is possible to provide high current outputs into the 10’s of thousands of Amps.

Power phase balancing equipment. Phase balancing provides re-distribution of a single-phase resistive load across a three-phase system. Such equipment is employed where a single-phase resistive heating load has alternative supplies from either the general distribution system, or a generator for security of supply, or there are limitations of single-phase loading imposed by the local supply authorities.

Power Voltage Stabilisers. The Voltage Stabilisers designed, and manufactured by Transformers & Rectifiers Ltd are for use within power distribution systems. Capacities range from 20 kVA through to 10 MVA, and are based on our Voltage Regulating Transformer that provides continuously variable on-load supply correction.

Power Rectifiers. Transformers & Rectifiers Ltd design, and manufacture Controlled, Thyristor, Rectifiers for process electro-type applications, and Un-Controlled, Diode, Rectifiers for bulk supplies such as Traction applications. Again these are bespoke products and as such a number of cooling techniques, enclosure arrangements etc. can be provided.

Stand-alone units are offered up to the capacity of our transformer manufacturing facilities, typically allowing us to offer unit capacities in the order of 5 MVA, dependent of specification details, and with an output current of up to 30,000 Amps. Beyond these capacities Transformers & Rectifiers Ltd offer multiple units for combined operation.

Customer specific products. While most of the equipment produced by Transformers & Rectifiers Ltd could be used in a number of different applications some products have been developed in conjunction with specific client’s to such a degree that they would have no practical application elsewhere.

Typically these products call for tight tolerance mechanical arrangements, as well as the normal demands on electrical aspects of the equipments, to ensure compatibility with client’s product. Such products include power, and monitoring equipments for the Medical Industry, and Security X-ray Units.  

Small components. Although the majority of Transformers & Rectifiers Ltd products are power components there are a wide range of small components within the product range. These include:

·        Partridge Audio Transformers, and chokes. Transformers & Rectifiers Ltd continue to produce a standard range of product to the original Partridge Transformers Ltd designs, and specifications.

·        AC reactors, DC chokes, and Auto Transformers for the Drive Control Industry.

·        Transformers & Rectifiers Ltd also hold many original designs, and specifications, appertaining to products produced by Southern Transformer Products, commonly known as STP, Gresham Transformers Ltd, GTL, and Partridge Transformers Ltd.  These companies provided vast amounts of small product to the likes of the Ministry of Defence (M.O.D.) under a wide range of NATO Stock Number. Transformers & Rectifiers Ltd maintains a database that enables cross-referencing of many of the original manufacturers’ part numbers, and specifications, to be referenced to a NATO Stock Number.

Site Service, Spares, and Repair.

Transformers & Rectifiers Ltd operates a dedicated Service Department. In addition to servicing, and commissioning Transformers & Rectifiers own brand products, the Service Department are able to offer technical, and spares support for a wide range of product originally manufactured by the various companies that Transformers & Rectifiers Ltd have acquired over the years. These companies include:

·        Allenwest Brentford Ltd

·        Brentford Electric Ltd 

·        Goodyear Transformers Ltd (Power Transformers)

·        Gresham Transformers Ltd

·        Partridge Transformers Ltd

·        Southern Transformers Ltd

Quality Control.

Transformers & Rectifiers Ltd operates a full quality management system that has been assessed to BS EN ISO 9001: 2000.

Technical Profile.

Due to the nature of the products that Transformers & Rectifiers Ltd provides technical input commences from the first contact with our Sales force. The majority of our Sales force have engineering experience, and in some cases are able to take a project through from initial concept to final product design.

Transformers & Rectifiers Ltd boasts an experienced in-house electrical design department. The team, accomplished in a wide range of disciplines that encompass all aspects of the design of the company’s product range, work with Sales to ensure a seamless transit from enquiry through to production of the final goods.

Our experienced, in-house, mechanical design team caters for mechanical aspects of the Transformers & Rectifiers Ltd product range, using both CAD, and traditional draughting techniques, depending on which is most suitable for the project in hand. 

Contracts Profile.

Transformers & Rectifiers Ltd operates a Sales and Contracts department that are engaged in every aspect of contract management from initial enquiry through tendering, negotiation, processing, and monitoring of purchase orders, and contracts, to final invoicing, and preparation of final contract documentation, where applicable.

Manufacturing Profile.

Transformers & Rectifiers Ltd facilities occupy approximately 6000 square metres. The Works are equipped with the machinery, and processes for effective production of the company’s range of products.

The functions carried out include:

• Quality assurance, and Goods inwards inspection
• Winding, and coil processing
• Core cutting, and assembly
• Fabrication
• Assembly, and processing of assemblies, and fluid
• Painting, and finishing
• Testing, and Inspection
• Despatch

To support these activities Transformers & Rectifiers Ltd have numerous winding machines, including a foil-winding machine with a capacity of up to 2.5 mm thick copper, at a maximum width of 1.2 metres, core cutting, and punching plant; varnish enveloping plant; various drying, and baking ovens; fluid processing plant; fabrication facilities, and painting plant.

Our largest crane has a 15 Tonne lifting capacity, although we have of course produced heavier equipments. 

Test facilities allow routine, and temperature rise (type) testing to be performed in accordance with BS EN 60076. Alternative standards, or tests, can be considered if required. Where alternative type, or special testing is required, third party test stations may be used if we are not able to accommodate the requirement in-house.