Power Factor Correction on Transformers?? Will there be a KW reduction?

[gar]

140825-0917 EDT

prs1jazz:

What are your max and min power values during the day shift when production is running? What is the typical kWHs per day?

If the entire heating process from room temperature to melted and ready to pour is by induction heating, then why?

In a steam powered electrical generation and distribution system the electrical energy available at your meter is about 30% of the stored energy in the input coal, gas, or oil source. Induction heating is probably no more than 50% efficient in converting electrical energy into your melt. Thus, total input to output thermal efficiency is possibly 15%. Someone else may be able to provide more accurate figures.

What is the best possible efficiency you can obtain by direct use of the coal, gas, or oil source to heat the melt? I will guess at 50% to 70%. Is there a technical reason the entire melt process has to be by induction heating?

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[Jraef]

One thing worth pointing out here, it is not the TRANSFORMER that is the cause of the poor PF, all it does is pass-through whatever else is happening. The CAUSE of your poor PF is the induction furnace itself. All the transformer does is to allow for higher current within the furnace, which is how the heat is created, without having to have high voltage AND high current. You can add PFC caps to correct the PF of that induction furnace, and it would be worth pursuing IF your utility is penalizing you for the .6PF. But the actual kW consumed will not change enough to make that worth doing as the only basis.

SOME of the losses in your circuit are what are referred to as "copper losses" or I²t losses, being based on the current flowing through the conductors. By correcting the PF, you will lower the current through the conductors UP TO the point where the capacitors are connected by the amount of amps represented by the kVAR provided by the capacitors. But here's the quick-and-dirty of it. Of all of the losses in your circuit, maybe 25% of them are directly related to the load itself, and of that 25%, maybe 30% of THOSE losses are copper losses, and of those copper losses, you only SAVE on the DIFFERENCE of the reduction by the caps, so maybe 5% at most (probably less). So that is 5% of 30% of 25%, so 0.375% of the total power through the circuit, and only while at full power, so the kWh as read by your meter is infinitesimal. Subtract from this the parasitic losses inside of the capacitors themselves (it's not much, but it's there) and the actual energy savings realized would mean that the "payback", defined as ROI on the cost of the capacitor installation, gets stretched out to being decades...

But again, if the PoCo is PENALIZING you for poor PF, then THAT is a valid reason to pursue it.