May 2024 Volume 6

EQUIPMENT & TECHNOLOGY

Individual Coil Control Ultimately, to maximize the efficiency of an induction billet heater, controlling the power distribution across the induction heating coil during heating will help prevent energy from being wasted during the heating process. Figure 6 shows an Inductoforge® Billet Heating System offered by Inductoheat and other companies in the Induc totherm Group The InductoForge® Billet Heater is a modular power supply approach with an induction heating coil mounted directly on top of each power supply. The coil’s close proximity to the power supply output connection reduces the connection distance between the output heat station and coil, thus reducing electrical losses. In addition, the Inductoforge® Billet Heating System's modular power supply configuration allows for controlling the power to each individual coil to optimize the heating process. This advanced control enables forging shops to configure the system for a wide range of production requirements, optimizing electrical usage and maintaining proper heating uniformity. In summary, electrical efficiency can be affected in several different areas. Understanding these areas can help maximize the output of your induction billet heater and reduce operating costs. Consulting with your induction heating supplier to determine the best equip ment design and setup will help you get the most out of your equip ment. References: 1. Collin A. Russell, Reducing Operational Costs and Energy Demand in Induction Heating, Madison Heights, MI. 2. Valery Rudnev, Ray Cook, Don Loveless and Micah Black, Hand book of Induction Heating, New York, 2003 Brian Lockitski Project Engineer – Forging Inductoheat Inc.

Ultimately, coil efficiency would require every billet diameter to have a special coil design to minimize the coupling gap. Unfortunately, this is not an economical solution; therefore, a balance between billet diameter range and downtime for changeover is a result. As a rule of thumb, billet range in a single coil design of the smallest billet is 70% of the largest billet diameter. It should be noted that other coil design factors such as configura tion of copper tubing used (square or round tubing), copper tubing size (width or diameter), copper wall thickness, number of copper turns and spacing of copper turns all influence coil efficiency. Each of these factors affect the distribution of current in the coil and thus the magnetic field that induces current in the workpiece. Consideration of each and every one of these factors when designing the induc tion heat coil could affect the overall efficiency by as much as 10%.

Power Supply Today’s solid state power supplies come in several different designs. The devices utilized in the power supplies vary from supplier to supplier and operating frequency. Devices such as silicone-controlled rectifiers (SCR) have been reliable for over 50 years in billet heating applications. Other devices such as insulated gate bipolar transistors (IGBT) offer an alternative for applications in heat treating. Regard less of which device is utilized for the solid-state power supply, the efficiency ratings are 93-95% efficient with constant power factors of 0.95.

An Inductotherm Group Company Email: blockitski@inductoheat.com Phone: 248-585-9393 ext. 5006

Figure 6: InductoForge Billet Heater

FIA MAGAZINE | MAY 2024 14