From Motors and Drives

IEC Ratings
At this point, it would be helpful to briefly review IEC motor ratings and then compare IEC with NEMA. The motor market today has become more global, with IEC rated motors on equipment exported from Europe.

IEC is the acronym for the International Electrotechnical Commission. IEC, like NEMA, establishes and publishes mechanical and electrical standards for motors. Many IEC standards have been nationalized for a specific country, such as Germany, Great Britain, or France.

Though NEMA and IEC standards use different terms, they are essentially similar in ratings and in many cases are interchangeable. NEMA standards are probably more conservative, which allows for interpretations in design. IEC standards are more specific and categorized. They are typically more precise.

Both IEC and NEMA use letter codes to indicate mechanical dimensions. They also use code letters to indicate general frame size. The NEMA and IEC dimension codes are not interchangeable, nor are the frame sizes (exception being the 56 frame, which is the same in NEMA and IEC).

As expected, NEMA designations are listed in inches and horsepower, whereas IEC designations are listed in millimeters and kilowatts. NEMA lists a handful of enclosure designations and descriptions, whereas IEC uses numbers.

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Products & Services
AC Motors
AC motors include single, multiphase, universal, induction, synchronous, and gear motors. They also include servomotors.
Motor Contactors
Motor contactors are relays with large current capacity for connecting and disconnecting a motor from the power supply. Typically, motor contractors are multi-pole for control of all current carrying conductors.
Motor Controllers
Motor controllers receive supply voltages and provide signals to motor drives that are interfaced to motors. They include a power supply, amplifier, user interface, and position control circuitry.
Brushless Motors
Brushless motors are synchronous electric motors that have a magnetically (AC induction) or electronically (DC) controlled commutation system instead of a brush-based mechanical commutation system.
Motor Starters and Contactors
Motor starters and contactors are motor-starting devices. They combine a contactor with overload protection and are designed for starting AC or DC motors.

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