In my last post, I briefly touched upon the many features of precious metal and graphite brushes. But what if you are not able to pick the brush type simply because you are still deciding whether to choose Motor Generator? So you may consider – Which commutation system would be more effective for my design?
Operating Life: One of the primary questions to ask yourself – what is your duty cycle and desired service life? If you are looking for a motor using a longevity expectancy, look at a brushless motor. Brushed motor life is limited by the brush type and will attain 1,000 to 3,000 hours on average, while brushless motors can attain tens of thousands of hours on average, because there are no brushes to wear. The limiting factor is the wear on the bearings.
Efficiency: When contemplating between brushed and brushless motors, one would believe that brushless motors could have a higher overall efficiency – however, it is in reality the contrary with Maxon, due to the iron-less core brushed motors design. With this particular design, stator magnetization is permanent and there are no eddy current losses. However, you will find eddy current losses within our brushless motors, which heat the material due to the electrical resistance and, therefore enhances the losses. The eddy currents’ amplitude is proportional towards the speed; the Joule losses increase with all the square from the induced currents, hence the Eddy current power losses increase using the square of the speed. Overall, the greater speeds, the greater the eddy current losses in brushless motors.
This is just an overview of motor efficiency, and that we also recommend taking into consideration the efficiencies within your full drive system, such as gearboxes and controllers.
Brushed DC motors can just be actuated with a DC voltage supply – even a battery. Brushless motors are slightly more complicated and need to be electronically commutated with a controller, enhancing the components and expense from the overall system. Depending on the level of precision required, one could decide sensorless block commutation, block commutation using Hall Sensors, or sinusoidal commutation utilizing the Hall sensors with or without an encoder can give them the final results they want.
These are simply a few characteristics to think about when choosing a commutation system. If you happen to find yourself in a standstill in your decision, our experienced Sales Engineers throughout the world are awaiting your call.
The content How Electric Motors Work explains how 1.5 N.M 5.8 A Stepper Motor work. In a typical DC motor, you will find permanent magnets on the outside as well as a spinning armature on the inside. The permanent magnets are stationary, therefore they are known as the stator. The armature rotates, so it will be known as the rotor.
The armature contains an electromagnet. When you run electricity into this electromagnet, it produces a magnetic field inside the armature that attracts and repels the magnets in the stator. So the armature spins through 180 degrees. To keep it spinning, you have to alter the poles in the electromagnet. The brushes handle this transformation in polarity. They make contact with two spinning electrodes linked to the armature and flip the magnetic polarity from the electromagnet since it spins.
This setup works and is also simple and cheap to produce, but it has many problems: The brushes eventually break down. Since the brushes are making/breaking connections, you get sparking and electrical noise. The brushes limit the maximum speed from the motor. Getting the electromagnet in the heart of the motor causes it to be harder to cool. The use of brushes puts a restriction on how many poles the armature can have. Using the advent of cheap computers and power transistors, it became possible to “turn the motor inside out” and get rid of the brushes. In a brushless DC motor (BLDC), you put the permanent magnets on the rotor and you also move the electromagnets to the stator. Then you certainly make use of a computer (connected to high-power transistors) to charge the electromagnets since the shaft turns. This method has a variety of advantages:
The poles on the stator of a two-phase BLDC motor employed to power a pc cooling fan. The rotor has become removed. Since a computer controls the motor as opposed to mechanical brushes, it’s more precise. The pc gqbemn also factor the rate of the motor in to the equation. This makes Brushless Motor 24v better. There is no sparking and much less electrical noise. You will find no brushes to wear out. Using the electromagnets on the stator, these are very easy to cool. You will have a great deal of electromagnets on the stator for additional precise control. The only real drawback to a brushless motor is its higher initial cost, but you can often recover that cost through the greater efficiency on the life of the motor.
FENFA Machinery?Electronics CO.,LTD . is located in the vicinity of the Shenzhen Baoan International Airport, the registered capital of 40 million yuan, with 13500 square meters of factory building, with more than 800 employees, is a professional engaged in R & D, manufacturing and sales of micro vibration motor of private enterprises. The products are widely used in mobile phone, tablet computer, intelligent wearable,security, toys (Mobile Games), video camera, aeromodelling UAV, household appliances, POS machine, printer, camera flash, massage health care equipment, robotics and medical equipment and other fields.
FENFA Machinery?Electronics CO.,LTD
Address:Juguang Industrial Zone, Juguang Village, Tiancheng Township,Yueqing City, Zhejiang Province
E-mail: [email protected]