One must know a little before jumping in. Size of furnace is frequency reliant, for example. If you were to apply a 1,000 Hz machine to a small furnace (say a 10 pound capacity), it wouldn't melt, although it might create some heat. They operate through a reasonable range, but achieve maximum efficiency at the proper frequency for the furnace size. In addition, how the furnace is charged makes a difference, as it affects heat generation. If miniscule particles are to be melted, without a heel to be heated, you'd need a much higher frequency power supply in order to induce the necessary heat.
To my knowledge, the modern induction furnace pretty much runs without intervention from the operator, but that's not true of the first and second generation machines. Because reactance changes as the charge melts, power factor correction is required constantly, and is accomplished by switching in or out a series of capacitors.
I'd be cautious about investing the kind of money an induction furnace costs if it was made in China. My chief concern would be the availability of replacement parts. While their units are not cheap, they are far less expensive than American built furnaces of the third generation.
Another consideration. Unless I didn't explore deeply enough, I took note that they were discussing a 380 primary voltage. That could prove troublesome for US individuals, as that isn't a common voltage for us. I was somewhat further alarmed to read of the limited melting capacity of the units offered. My 50 kw unit should be capable of melting 200 pounds of steel, although an ideal charge would be 100 pounds (determined by the coil and furnace). As the volume of the charge increases, so, too, does melting time. I would expect that a 50 kw unit would be recommended for melting 100 pounds of ferrous materials. If I'm wrong, please feel free to correct me.
First generation units (transformer and spark gap) were reputed to operate @ 25% efficiency, with the second generation machines (motor/generator) operating @ 50% efficiency. Third generation machines approach 100% efficiency, which is what troubles me about the limited melting capacity of the Chinese unit. It must be very light duty, or well under rated. I have no clue which would be true.
If you're interested in induction melting, it wouldn't hurt to keep an eye open for a used second generation unit, similar to mine. They appear on the market occasionally, and have been known to be procured for as little as a few hundred dollars. There are a few makers, one of which is Inductotherm, who marketed smaller units. I am aware of both 20 and 30 kw units. Ajax Magnethermic, too, made smaller units, although they don't appear to be as common as the Inductotherm. The problem is, they (all) require 3 phase service, so you may be limited in options. If you were to get a small enough unit, it most likely would operate on single phase, but it would also be quite limited in its capability, so you couldn't cast large items.
I was discussing frequency. My unit has an output of 3,000 Hz. (@ 400 volts) They (Ajax Magnethermic) built the identical unit that operated @ 10,000 Hz, What it would be used for would determine the required frequency, along with furnace capacity. If one intended to melt chips, for example, the 10,000 Hz machine would be a better choice than the 3,000 Hz machine.
As size of the furnace increases, the frequency demand is lowered. There are line frequency induction furnaces, but they are huge--far beyond anything a home shop would even consider (50 ton capacity, for example).
Hope some of this helps.
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