HISTORY OF BRUSHLESS DC MOTORS
Brushless DC motors (BLDC) are an invaluable part of industry today. Use of these motors can save nearly any industry a great deal of time and money under the right circumstances. The BLDC motor actually represents the end, or at least the most recent end result, of a long evolution of motor technology. Before there were brushless DC motors there were brushed DC motors, which were brought on in part to replace the less efficient AC induction motors that came before. The brush DC motor was invented all the way back in 1856 by famed German inventor and industrialist Ernst Werner Von Siemens. Von Siemens is so famous that the international standard unit of electrical conductance is named after him. Von Siemens studied electrical engineering after leaving the army and produced many contributions to the world of electrical engineering, including the first electric elevator in 1880. Von Siemens’s brush DC motor was fairly rudimentary and was improved upon by Harry Ward Leonard, who nearly perfected the first effective motor control system near the end of the 19th century. In the year of 1873 Zenobe Gramme invented the modern DC motor. This system used a rheostat to control the current in the field winding, which resulted in adjusting the output voltage of the DC generator, which in turn adjusted the motor speed. The Ward Leonard system remained in place all the way until 1960, when the Electronic Regulator Company’s thyristor devices produced solid state controllers that could convert AC power to rectified DC power more directly. It supplanted the Ward Leonard system due to its simplicity and efficiency.
۱٫۱٫۱ Advent of Brushless DC Motors
Once the Electronic Regulator Company maximized the efficiency of the brush DC motor, the door was opened for an even more efficient motor device. Brushless DC motors first made the scene in 1962, when T.G. Wilson and P.H. Trickey unveiled what they called “a DC motor with solid state commutation.” Remember that
the key element of brushless DC motors as opposed to brush DC motors is that the
brushless DC motor requires no physical commutator, a revolutionary difference. As the device was refined and developed, it became a popular choice for special applications such as computer disk drives, robotics and in aircraft. In fact, brushless DC motors are used in these devices today, fifty years later, so great is their effectiveness. The reason these motors were such a great choice for these devices is that in these devices brush wear was a big problem, either because of the intense demands of the application or, for example, in the case of aircraft because of low humidity. Because brushless DC motors had no brushes that could wear out, they represented a great leap forward in technology for these types of devices. The problem was that as reliable as they were, these early brushless DC motors were not able to generate a great deal of power.
۱٫۱٫۲ Modern Brushless Dc Motors
That all changed in the 1980s, when permanent magnet materials became readily available. The use of permanent magnets, combined with high voltage transistors, enabled brushless DC motors to generate as much power as the old brush DC motors, if not more. Near the end of the 1980s, Robert E. Lordo of the POWERTEC Industrial Corporation unveiled the first large brushless DC motors, which had at least ten times the power of the earlier brushless DC motors. Today, there are probably no major motor manufacturers that do not produce brushless DC motors capable of high power jobs. Naturally, NMB Tech offers a wide variety of brushless DC motors for you to choose from, in sizes from 15mm in diameter to 65mm in diameter, Watt’s output range from 0.7 to maximum of 329.9. Industries with motor needs have relied on brushless DC motors for nearly fifty years, and there is every reason to believe that they will continue to do so for decades to come. Take a look at some brushless DC motors today.
۱٫۲ INTRODUCTION OF BLDC MOTOR
Brushless Direct Current (BLDC) motors are one of the motor types rapidly gaining popularity. BLDC motors are used in industries such as Appliances, Automotive, Aerospace, Consumer, Medical, Industrial Automation Equipment and Instrumentation. As the name implies, BLDC motors do not use brushes for commutation; instead, they are electronically commutated. BLDC motors have many advantages over brushed DC motors and induction motors. A few of these are:
In addition, the ratio of torque delivered to the size of the motor is higher, making it useful in applications where space and weight are critical factors. In this application note, we will discuss in detail the construction, working principle, characteristics and typical applications of BLDC motors.
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in future we will add some brushless electronic projects with micro controller