High Efficiency Motors - Is there a paradox?

You are working from some general misinformation. Higher PF is a better thing, the overall energy delivered by the utility will / can be less, although the end user will not necessarily benefit directly. But the end used will definitely benefit directly from a decrease in power consumption due to improved efficiency. There is less wasted energy in the form of heat losses (mainly magnetic and friction. So they get either more work from the same energy input, or lower energy input for the same work performed. Minor differences in slip speed are almost completely irrelevant.

Please refer to the discussion details wherein it is mentioned that higher efficiency motors have LOWER PF so there is no misinformation. A motor with lesser PF draws more current than one with a higher PF of the same rating, isn't it so?

JRaef was on the subject and gave you a good answer.

Electricity supplier insist on connecting capacitor of proper rating to the motor to improve PF.With low PF the current drawn is more compared to good PF for same output power.To increase torque we want more current so resistors as load is connected in rotor winding of say slip ring indn motor.

Anecdotal evidence that I've been getting from maintenance companies is that high-efficiency motors are flimsier that 'regular-efficiency' ones and break down significantly more often and they don't last as long. They're just not as robust.

Also, they don't necessarily save on electrical consumption ... they'll do so if fully loaded, but at low loads, there's little benefit. This won't necessarily mean much in the future if the cost of motors drops to that of the then-cost of 'regular' motors, but there's no getting around lower robustness unless new science and enginering improves motor design.

Cheers! DZ

I too am dubious about the (general) statement that high efficiency motors have lower power factors. However, putting that aside, power factor can readily be addrsssed by adding a properly sized capacitor, either right at the motor, or as part of an automatic bank after the Utility meter.