Go to GlobalSpec.com Home
Free Registration 
GlobalSpec Home
Alert   Product Alerts
Keep current on the latest products, new suppliers, and technical articles of interest to you. (See Topics)
Chapter 3: AC and DC Motors - AC Motors: AC Motor Types
By Dave Polka
Find Products & Suppliers related to
Chapter 3: AC and DC Motors - AC Motors: AC Motor Types
 
Research
Chapter 3: AC and DC Motors - AC Motors: AC Motor Types
From Motors and Drives

AC Motor Types

Introduction
AC motors can be divided into two major categories-asynchronous and synchronous. The induction motor is probably the most common type of asynchronous motor (meaning speed is dependent on slip). When reviewing induction motors, there are two rating designations-NEMA and IEC.

Another type of asynchronous motor is the wound rotor motor. This type of motor has controllable speed and torque because of the addition of a secondary resistance in the rotor circuit. A third type of popular asynchronous motor is the single-phase motor. The single-phase AC motor will not be covered because of their limited use in industrial applications when connected with variable-frequency drives.

The synchronous motor is inherently a constant-speed motor, when operated directly across the line. This type of motor operates in synchronism with the line frequency. Two types of synchronous motors are non-excited and DC-excited.

The basic principles of AC induction motors have been previously covered. In this section, attention will be given to motor designations, ratings, and designs.

Standard AC Induction Motors (NEMA and IEC)
NEMA frame motors are in widespread use throughout U.S. industry. This motor...


More >>
© 2003 ISA

Products & Services
Gearmotors consist of an AC or DC motor with an integral gearbox or gear head that steps delivered speed up or down.
Motor starters and contactors are motor-starting devices. They combine a contactor with overload protection and are designed for starting AC or DC motors.
DC servomotors are generally small and powerful for their size, and easy to control. Common types of DC servomotors include brushless or gear motors.
AC servomotors are responsive, high-acceleration motors typically constructed as permanent magnet synchronous motors.
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.
Back to Top

Product Announcements
Automationdirect.com - NEW: NEMA Premium AC Motors
AutomationDirect offers a variety of AC motors from ΒΌ-100 Hp. New models offer premium efficiency from 1-100 Hp. These TEFC motors meet or exceed NEMA Premium ratings for reduced power consumption... (read more)
ABB Drives and Motors - High Voltage NEMA Motors, TEFC, 506AT - 688
NEMA cast iron motor is a cost-efficient, high voltage induction motor that can be delivered within days of ordering. (read more)
Benshaw, Inc. - Synchronous Starters
The Sync motor functions as an induction motor during start up. Once the motor approaches full synchronous speed, the Redistart DC exciter induces a constant polarity to the rotor causing the motor to... (read more)
Automationdirect.com - Motor Controls - Starters/Contactors/Overloads
Motor contactors, overload relays, and manual motor starters provide complete motor control solutions up to 300 horsepower. Starters accommodate motors up to 100 horsepower at 480 VAC, while MMS... (read more)
Baldor Electric Company - Variable Speed Motor High Torque to Inertia Ratio
New Reliance™ Finned Laminated Frame RPM™ AC Motor Offers Greater Power Density in a Smaller Frame Size. Engineered to provide increased torque density and more power, the new totally... (read more)
Yaskawa Electric America - Drives Division - G5 Drive 600 Volt
2 - 200 Horsepower General Purpose Vector Drive The G5 Drive 600 Volt produces an output of adjustable voltage and frequency to control the speed of a squirrel cage induction motor. This PWM design... (read more)
Bodine Electric Company - New 230/460 VAC Inverter Duty Gearmotors
Bodine Electric added over twenty new 230/460 VAC, variable speed, three-phase gearmotors and motors to their Pacesetter™ product line. These new models are ideal for factories where various... (read more)
ARC Systems, Inc. - Induction Motors
ARC's complete lines of AC Induction Motors are manufactured using a squirrel cage rotor utilizing both aluminum and copper bars. Speed and torque can be tailored to individual requirements by... (read more)
Bodine Electric Company - Standard Products Reduce Development Time & Cost!
Bodine Electric Company offers now over 1,000 standard models of AC induction, permanent magnet DC, and brushless DC fractional horsepower (<1 HP, 746 Watts) gearmotors, motors, controls, and motor... (read more)
 
Back to Top

Topics of Interest
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... (Read More)
AC and DC motors are the two major types in use today that are related to the industrial and HVAC applications. These motors provide the speed, torque, and horsepower necessary to operate the... (Read More)
PERFORMANCE Ac induction motors are designed to produce their rated power at a certain speed at a specific line voltage, line frequency, and ambient temperature. These motors will also operate at a... (Read More)
Control of Speed, Torque, and Horsepower Control of Speed The speed of a squirrel cage motor depends on the frequency and the number of poles for which the motor is wound. The higher the frequency,... (Read More)
What are the two main parts of a DC motor and what is the purpose of each? What is the purpose of the brushes? Why are the laminations in the armature skewed? What is the purpose of the... (Read More)
Back to Top