Why choose a DC motor?
Many applications require a high starting torque. The D.C. motor, by its very nature, has a high torque vs. speed characteristic, enabling it to deal with high resistive torques and absorb sudden rises in load effortlessly; the motor speed adapts to the load. In addition, D.C. motors are an ideal way of achieving the miniaturization that is so desirable to designers, since they offer a high efficiency as compared with other technologies.
DC motor solutions benefits:
- High starting torque: The D.C. motor, by its very nature, has a high torque vs. speed characteristic, enabling it to deal with high resistive torques and absorb sudden rises in load effortlessly. The speed of the motor adjusts to the load.
- Miniaturisation: D.C. motors offer higher effi ciency than other designs.
- Safe operation: The low voltage supply provides a level of safety that complies with machine requirements EN 60335-1 and IEC 335-1 “Safety of household and similar electrical appliances”.
- Simple and cost-effective speed, torque and position servocontrol.
How does a Brushless DC motor work?
when maximum lifetimes with no maintenance, no audible noise and no EMI are desired, the Brushless DC Motor is the right solution.
Brushless DC Motor components are made up of three main elements:
- A fixed part, the stator, which has three groups of coils, called the three phases of the motor. These coils operate as electromagnets and generate various orientations of magnetic field regularly distributed around the central shaft of the motor.
- A rotating part, the rotor, which has permanent magnets. Like the needle of a compass, these magnets permanently drive the rotor to try to align itself with the magnetic field of the stator. For optimum service life of the motor, the rotor is mounted on ball bearings.
- Three “Hall effect” magnetic sensors. These sensors provide information on the position of the rotor magnets at all times.
The Brushless DC Motor requires an electronic control to activate the phases of the motor. Advances in electronics have made the control smaller, less expensive and capable of offering many value added features.
How does a Brush DC motor work?
Brush DC Motors are also made of three main components:
- A stator made up of a metal enclosure surrounding attached magnets that create a permanent magnet field.
- An interior rotor, which is attached to the rotating output shaft. It has a metal structure supporting copper wire coils which, when energized, become electromagnets. Through the attraction of opposite magnetic poles and the repulsion of like poles a torque is created that turns the rotor.
- A commutator, which creates rotation by selectively energizing the rotor coils. Basically a segmented copper assembly energizes the coils when it makes contact with a conductive carbon brush.
Hence, the name Brush DC Motor. However, the carbon brushes wear over time, and the commutator does too, although more slowly. Therefore, the Brush DC Motor has a finite life. In addition, the brushes making contact with the rotating commutator are also a source of noise: not only audible noise, but also electrical “noise” in the form of electromagnetic interference (EMI) as a result of the minute arcing that occurs when contact is made and interrupted. In many applications, however, the Brush DC Motor can be a reliable solution.
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