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Efficiency and speed – a win/win for IGBT technology

Building an extensive business refurbishing and upgrading second-hand furnaces from 1999 through the noughties has introduced expertise and entrepreneurship at Meltech Ltd which saw them swiftly move on to build their own coreless induction furnaces, including the development of their own invertor system. Now, 23 years later, the company has become synonymous with IGBT technology.

Now occupying a 1,000sq mtr site, with the capability of even further expansion, the company is riding high thanks to its refinement of IGBT inverter technology and ability to offer a wide range of induction melting furnace bodies including tilting, rollover and crucible drop coil styles, plus a vast range of spare parts and service for various brands of furnace and melting equipment. Commercial director Steve Macey details the history: “We had built a very nice business refurbishing existing equipment and bringing it up to modern standards, then when Electro Magnetic field emission standards came into effect in the 2000s, we were faced with the dilemma that the cost of rebuilding and upgrading older equipment was becoming prohibitive. So, we decided to make new furnace bodies.”

The foray into part-new machines then led to the inevitable, as Macey puts it: “We got a taste for making new stuff.” As a team of experienced electronic and mechanical engineers, the desire to find solutions to customers’ induction melting dilemmas demanded a more all-encompassing approach. Thus, by 2013 Meltech had developed their own range of induction furnace bodies which were branded as Mag-Melt, an abbreviation for magnetic melting. Soon after the company ventured into IGBT inverter technology. “We learned pretty quickly that this technology was noticeably faster and more efficient,” Macey explains. “By 2017 we had developed our first IGBT invertor which was out for trial at Yeovil Precision Castings (now Tritech UK). When we accessed the performance data, we discovered it was significantly better than previous systems. Melt time was significantly reduced, as was energy consumption. We then went on to sell more.”



There then followed constant product development with bigger machines being built up to 750kW power rating. Extra functionalities were also incorporated with constant software improvements. Auto sinter, interconnectivity, data download and monitoring, fault finding – all able to be accessed remotely using portable devices. “Basically, we have made the system totally flexible,” Macey says. “The software lives with the machine and always evolves thanks to the upgrades we undertake as we service each machine, essentially the system or its software never becomes obsolete.” The extension to the life of machines has been a real bonus for customers and has enabled Meltech to grow the business, as has the adoption of digitised control which has further extended the flexibility of the furnaces.

The move into digital technology and remote monitoring has been an ongoing trend in recent years and this is very much a part of standard thinking now. The equipment and software has been designed for ease of detection and solution. Macey says: “Everything the machine is doing is being measured constantly. There are multiple sensors which are constantly monitoring and displaying the system conditions, in the event of a fault, pressing the HMI indicator brings up the relevant page on the digital manual and suggests possible causes and solutions. There is also a detailed alarm history on the machine, both can be analysed online and by USB backup. We and the customer can access the machine remotely from anywhere in the world, we can advise how to fix a problem or we can initiate a call-out.”



Having mastered the melting technology, the next step has been integrating into the auxiliary equipment such as PLC control and water cooling systems. “The inverter now talks directly to the water cooling PLC,” Macey explains. “Everything on the system – temperature, overrun times, settings – are all set up and run from the HMI on the inverter. It also controls the water cooler with individual controls for every single fan – this means that you only run the individual fans that you need, rather than having pairs or triple sets running. It’s such a bonus in terms of energy efficiency.”

Efficiency is very much the order of the day and another tweak to original thought process that aids this is the use of magnetic shunts in each furnace body. Instead of butting up against the induction coil, In smaller furnaces Meltech advocates pushing the shunts away from the coil in order to reduce magnetic field density and enable the furnace to run cooler, another advantage is that there is a significant reduction in the use of insulators which reduces the chance of coil arcing whist making maintenance simpler and quicker.

“Our systems consume less energy than equivalent SCR or thyrister driven induction furnaces,” Macey says. “It’s all about melting for less cost and less energy.”

Macey puts the company’s success down to their many years of working with a range of furnaces and customer requirements plus their adoption of IGBT technology which, he says has been widely adopted elsewhere. “In other industries, IGBT’s have wiped out SCR technology as a switching device. For example, all electric vehicles are IGBT driven along with almost all AC motor drives. SCR’s have been superseded by IGBT transistors in most industries.

“In terms of our product lines, below 750kW most mainstream melting tends to be IGBT although higher power systems are in development right now.” This transformation has been a positive for Meltech, having got on board with the technology early on it has seen a decline on the company’s original primary business. “Up until eight years ago we were the foremost supplier of rebuilt furnaces in Europe, but as IGBT sets were introduced customers were given a compelling choice to make, at double the cost of a rebuilt second hand machine, an IGBT system could pay back that difference in less than three years in reduced energy costs, furthermore UK tax incentives introduced for capital equipment purchases during and after Covid, have enabled foundries to invest in the latest melting technology, and we are thankful for that.”

The company also still houses an extensive spare parts facility, carrying parts for a wide range of their own and competitor equipment and operates an easy to use spare parts online catalogue. Indeed, such has been the demand for new furnace technology that the company has expanded into the full 1,000sq mtr of its site in Haverhill, Suffolk (UK), including extra production and administration space, a new boardroom and increased test room facilities.



In recent years, Meltech has become particularly experienced in the provision of modular systems, where platforms are part of the installation. Furnaces are pre-assembled in the Meltech factory, then dismantled, transported and re-assembled at customer’s sites as a modular install – an overall design that has been embraced by many customers requiring a quick installation. Andrew Drage, sales manager, says repeat orders are now a significant part of the company’s business. “Around half of our orders now come as a result of the customer buying their first Pulsar IGBT then realising the benefits, decide to replace their other SCR’ sets.” he says.

Back in early 2018 Archibald Young Ltd invested in a brand new Meltech induction melting system to replace a now unreliable machine which dated back to the 1980s, the new furnace comprised of 150Kw Pulsar IGBT Inverter with a twin crucible body drop coil arrangement at 100kg and 200kg capacities. As managing director Andrew Young explains: “The technology offered with this system was a departure from the existing equipment and the benefits were quickly felt with an improved efficiency and shorter melt time. So much so, when deciding to invest in new furnaces at our subsidiary company, Peel Jones Copper Products Ltd, the purchasing decision was an easy one and we installed another Pulsar IGBT Inverter, this time with two off 500kg fixed body tilting units”.

Andrew Drage says: “We are also known for special products such as carousel furnaces, Pre Tilt systems for accurate pouring and of course our IGBT power share where a single control panel feeds two furnaces simultaneously. This is a recent development for us, and I am not aware if any other company does this with a series driven IGBT inverter.” From humble beginnings to cutting edge technology, Meltech has invested in an efficient and controllable future for induction melting needs and continues to grow the business to support its extensive customer base.

Contact: Andrew Drage, sales manager, Meltech Ltd, Tel: + 44 (0) 1440 710603, email: [email protected] web:



Used as switching devices in the inverter circuit – for DC to AC conversion – for driving small to large motors, IGBT is considered an option to improve efficiency. With lower on-state resistance and conduction losses, and an ability to switch high voltages at high frequencies without damage, IGBT is ideal for driving inductive loads such as coil windings, electromagnets and DC motors.

Andrew Drage, sales manager at Meltech explains why the company’s Pulsar IGBT inverters have been making a difference in recent years. “The IGBT technology is all about efficiency and speed, with some installations having shown savings of up to 30 per cent via improvements in energy consumption and melt times. The Pulsar inverter is a thoroughbred IGBT series inverter, so it offers better efficiency like for like than other traditional SCR or thyristor driven system. The Pulsar IGBT can connect directly to a standard distribution transformer to drive all makes and types of induction furnace body.

“During customer installations, there have been instances where melt times have been reduced from 90 minutes to 55 minutes. While the performance exhibited during the melting and holding cycle has in certain circumstances reduced energy consumption to give the customer a very tangible cost saving and payback. One customer noted a decrease in power consumption from 125 to 60kW during their holding cycle.”