A fundamental understanding of the speed-torque curve it the key to specifying a dc motor that will do everything it needs to do. Much has been written about the process of selecting motors for applications in motion control. Motor selection can be complicated. The decisions to be made include whether to employ brushless or brushed dc, or stepper motors. Stepper motors are generally considered specialpurpose devices because they can't handle large inertial loads very well. And operation near their maximum torque ratings can take some finesse. • Shaft-bearing systems, commutation, and motor windings all factor into whether a specific motor will handle an intended application. • It is important to understand where the intended operating point lies on the possible torque-versus-speed curves. In contrast, dc motors are usually considered more general-purpose motioncontrol devices. They are a frequent choice for supplying variable speeds when precise speed regulation is not critical. They can handle brief overloads as well as frequent stops and starts. Dc motors are usually rated at a single speed and torque, and they can operate at rated conditions continuously. There are basic calculations that can point the way to using the right dc motor in the right situation. Parameters that define the best motor type for an application include the mechanical output power, the shaft bearing system, the commutation system, and the possible combinations with gearheads and sensors. The most important criteria include the required speed and torque and the commutation system. Of course, equations define these relationships. In this article, variables on the motor shaft (output) are identified with the subscripts Mot. For example, n gives the required motor speed. Parameters that describe the qualities of the motor have no special additional subscript. For example, stands for the motor's no-load speed. We'll discuss speed and torque requirements first. The
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DC motors are most commonly used in variable speed and torque applications. They include brushless and gear motors, as well as servomotors.
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.
AC motors include single, multiphase, universal, induction, synchronous, and gear motors. They also include servomotors.
DC Motor Drives
DC motor drives act as the interface and power supply between a motion controller and a DC motor.
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.
Portescap offers the broadest miniature and specialty motor product line in the industry, including Brushless DC technology. With speeds up to 1,000 rpm and Frame sizes from 12.7 mm (.5 in.) to 58 mm...
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Parameters that define a motor type are the mechanical output power, the shaft bearing system, the commutation system used, and the possible combinations with gearheads and sensors. The most important...
Basically, four different types of DC motors are used in industrial applications: series wound, shunt wound, compound wound, and permanent magnet. Several factors must be considered when...
General Principles of Operation-Stepper
A step or stepper motor is one in which electrical pulses are converted into mechanical movements. A standard DC motor, for example, rotates...
There are so many motors on the market today, from heavy-duty AC motors to tiny DC brushless and stepper motors. To use any of the motors users must have a full understanding of the application...
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...