Earlier this year a Swedish manufacturer, AB Lundbergs Pressgjuteri, placed an order with Otto Junker GmbH for a two new medium-frequency induction furnaces for melting aluminum at its foundry in Vrigstad. It was a "future-oriented" investment decision, according to the furnace builder.
Lundbergs produces high-pressure aluminum diecastings that it supplies to telecommunications, heavy vehicle, and machinery manufacturers, as well as to buyers involved in equipment engineering, electronics systems production, furniture making, and disability aids and equipment manufacturing.
The business previously contracted to source electricity from renewable sources, and expects to have converted all of its power supply to renewable energy within four years, anticipating a 40% savings (1 million kWh) on its previous energy consumption total.
Lundbergs Pressgjuteri recognized that induction melting will offer significant advantages over resistance-heated or gas-fired furnaces. One advantage is that the coreless induction furnace's bath movement allows return material to be stirred into the melt. Due to its light weight and small size, return material cannot be used in the foundry's current resistance-heated process (it is sold as scrap), so the new furnaces will help to optimize the foundry' resource and energy efficiency.
The new system consists of two, 1,000-kg furnaces operating in tandem via a 750-kW Duomelt frequency converter that will distribute power freely between the two furnaces operating in tandem.
The frequency converter will be equipped with IGBT modules to operate the system with a consistently high power factor (cos phi = 0.99 at the converter input.)
As energy efficiency is important to Lundberg Pressgjuteri, both furnaces have been fitted with an energy-saving coil to increase efficiency by up to 7%, especially when melting aluminum. The JOKS-Touch system with two operator stations is used to control, monitor, and document the melting process automatically.