Scheme of a homemade induction furnace
|Scheme of a homemade induction furnace|
Homemade Melting Induction Furnace
The current model of the induction furnace is shown in Fig. 1. The HF generator generates oscillations with a frequency of 27.12 MHz. It is assembled on four electron tubes (tetrodes). A neon lamp indicates that the device is ready for use. The handle of the variable capacitor (KPE) C is brought out. At the highest capacity of the KPI, a piece of metal placed (in the 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 - frameless, consists of 10 turns of wire PEV 0.8, the inner diameter of the coil is 12 mm. Capacitor C from the broadcast radio (with each second plate removed).
The power of the device is such that it instantly heats up to red heat, for example, a screwdriver. The melting rate of metal in induction furnaces depends primarily on the generator power, frequency, hysteresis losses, eddy currents in a 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 220 V AC through a rectifier. Capacitors C1 - ceramic or mica with an operating voltage of 1500 ... 2000 V, high frequency dr chokes.