Industrial AC Motors Categorized

By Naresh Kumar Surepelly

Industry Trends

Industrial motors can be categories as defined by the motors input voltage: Low Voltage and Medium Voltage. Many suppliers offer a range of products that fall into both segments.

Motor Segmentation by Voltage

Low Voltage (LV) Motors

Low Voltage Motors can be further segmented into the following categories.

Low Voltage Motors by Power Range

ARC has elected to capture the market in integral power ranges that best represent those influenced by minimal energy performance standards (MEPS) in each region, with motors above 375 kW/500 HP being the regulatory cut-off point.  Motors above the cut-off power rating are not subject to the MEPS.  The classification of low voltage AC motors and DC motors by power in this study considers the following power ranges shown in the table on the left.

Low Voltage Motors by Efficiency Class

ARC segments the LV motors market by IEC or NEMA classifications in regards to the power ranges that are set by regional MEPS.  Typically, the vast majority of LV motors in the IE1, IE2, IE3, and IE4 classes are labeled as General Purpose motors, but also include some Definite Purpose motors.

IE4 Super Premium Efficiency Motors

The IEC has officially defined IE4 as a level of efficiency, but not a distinct motor efficiency class like IE1, IE2, or IE3.  The IEC provides a specification for line-start permanent magnet (LSPM) motors that achieve IE4 levels of efficiency.  Line-start PM motors are basically an asynchronous machine that achieves synchronous operation at a certain speed.  These motors are typically IE3 motors with more copper windings and higher grade electrical steel.

Because the majority of suppliers have chosen to market their respective IE4 technologies as Super Premium and are selling them into industrial sectors to compete directly with IE2 and IE3 AC induction “squirrel-cage” motors, In addition to the asynchronous LSPM motors, these include:

  • Sensor-less, neodymium-based permanent magnet synchronous motors (PMSMs), like ones manufactured by Lafert Group, Leroy-Somer (Emerson), and WEG 
  • Electronically commutated permanent magnet (ECPM) motors, like ones manufactured by NovaTorque
  • Synchronous reluctance (SynRM) motors, like ones manufactured by ABB
  • Switched reluctance (SR) motors, like ones manufactured by Nidec
  • Amorphous metal (AM) + ferrite magnet (FM) motors, like ones manufactured by Hitachi Industrial Equipment Systems

Low Voltage Motors by Frame Type

ARC segments IEC and NEMA frame sizes at the global level in this report as shown on the left.  Frame sizes do exist outside of the IEC and NEMA ranges listed and are sometimes referred to as Above NEMA (ANEMA) and Above IEC.  These are often custom-made motors that do not have to meet efficiency standards set by regional MEPS.  ARC has elected to place these LV motors into the “Other” segment as described in the previous section.

Low Voltage Motors by Usage Environment

ARC segments LV motors by usage environment at the global level.  The hazardous segment will include motors with IP ratings suited for hazardous environments where dust, vapor, and ignitable/combustible flyings can create a dangerous operating environment.  The hazardous segment includes ATEX, Explosion Proof (XP), and all varieties of IECx hazardous specifications.

Low Voltage Motors with End-equipment Type

ARC segments the LV motor market by the type of end-equipment that is sold with the motor at point-of-sale. 

Medium Voltage (MV) Motors

Medium voltage (MV) motors are defined as asynchronous and synchronous AC induction requiring voltages in excess of 1kV. These motors can be connected directly to a local power grid or through an AC drive.  While developing the scope of this report, ARC Advisory Group focused on data solely pertaining to the MV motor market.  In order to do this, some important caveats pertaining to the scope of the report must be mentioned:

  • The term “high voltage” is often used to describe AC induction motors that require voltages in excess of 5-6kV.  ARC has elected to include high voltage motors in the general category of medium voltage motors which includes motors requiring voltages of 1kV to 13.2 kV and above.
  • To some extent, direct current (DC) motors compete with medium voltage AC induction motors in mostly the lower power ranges covered in this report.  ARC has elected to include these DC motors in the general category of medium voltage motors.

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