Do High-Efficiency Motors Save Energy?

Yes if installed correctly, Type, HP, service factor,temp rise, PF, then load match.

over an uncorrectly design one . mis size etc.

But note Eff,Pf, phases, and Voltage have nothing to do with determining the output watts of a motor

Eff = Output power (w) / Input power (w) ExI = w

since motor out put is in HP its 746 w per HP

not counting the Power Losses IxIxR = PL

conductor resistance, flux leakage, eddy currents and hysteresis losses

You have hit upon a fine point. The motor may be highly efficient but the system that was designed around it may take away the original efficiency. Which is why the entire system should be designed for a specific, efficient task, not just a single entity.

Yet we suffer from the fools around us who constantly insist that to reduce energy we simply have to replace or use a single device in an inefficient system.

Due to the terms of my parole, I have to stop writing now before I go into my politico manifesto. So I will spare you my (now up to) thousand page rant.

If high efficiency motors are used in conjunction with electronic efficiency controllers both single and three phase. These controls are an improvement on " Nola Energy Saving Technology"

It is is a very good system for motors which have to work with variable loads where it can adjust the efficiency to suite the load instantaneously it gives a cost saving on power consumption which is worth while. Motors which are designed to run on continuous loads which are designed for that load would not see much if any great power saving apart from varying mains voltage input.

Yes, they do save energy .The question should be : Are premium efficiency motors worth the price ? Well, it depends on how long they are operating . For assured energy saving always use variable speed with variable speed drive in lieu of a starter .