• The industry always thinks that we are losing on higher HP motors at high load factors.

• If we sum up the losses on hundreds of our lower HP motors, this will be very much higher.

• Please concentrate on your motors up to 10 HP motor where your per hour loss is around 2 KWH every hour and if you calculate  the Annualized Energy Loss of your existing motor, then you will take immediate steps to correct or replace the same.

• It is common for manufacturers of high efficiency motors to reduce the size of air gap between the rotor and stator, so as to reduce reluctance in the magnetic path, & subsequent magnetizing losses.

•  However, the closer proximity of the rotor and stator also increases the amount of harmonics induced into the rotor, resulting in higher rotor losses. Please keep in mind.

•  When a motor is to be supplied to a non-sinusoidal power source (i.e.: an adjustable speed drive), this closer proximity of the rotor and stator can result in significantly higher overall losses, as the increased harmonic heating of the rotor far outweighs the reduced magnetizing losses.

•  It may therefore make more sense to increase the air gap in light of above fact. A thorough review of all motor performance characteristics, including efficiency, will result in a motor selection that is an optimization of all performance features.

• The power factor of a motor is primarily influenced by rotor/stator air gap and the reluctance (grade of steel) of the stator core & rotor core material, with air gap dominantly...

• Motor manufacturers will often sacrifice power factor in favor of higher efficiency, since power factor is relatively inexpensive to correct later at the site of installation. But motor’s low efficiency can never be corrected after manufacturing and that too after installation at site.

• Have you analyzed your motor’s power factor parameters and please study where you can improve upon your system efficiency?

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