Scheme homemade induction furnace
|Scheme homemade induction furnace|
Homemade Induction Melting Furnace
The current model of the induction furnace is shown in Fig.1. The RF generator produces oscillations with a frequency of 27.12 MHz. It is assembled on four electron tubes (tetrodes). Neon lamp indicates the device is ready for operation. Handle of a variable capacitor (KPA) C is brought out. At the highest capacitance of KPI, a piece of metal is quickly heated and placed (in a crucible) in the coil L.
Fig.1. Generator circuit
To melt a piece of zinc, it is enough to heat it for 15 ... 20 s. Coil L is frameless, consists of 10 turns of the PEV wire, 0.8, internal diameter of the coil is 12 mm. Condenser C from broadcast radio (with every second plate removed).
The power of the device is such that it almost instantly heats up to red heat, for example, a screwdriver. The melting rate of the metal in induction furnaces depends primarily on the generator power, frequency, hysteresis loss, the eddy currents in the piece of metal and the rate of heat transfer to the environment. Lamps are recommended to be used powerful, but their number with parallel connection should not exceed four.
The furnace is powered by AC 220 V through a rectifier. Capacitors C1 - ceramic or mica with an operating voltage of 1500 ... 2000 V, Other high-frequency chokes.