BLDC motors (DC motors without brushes), also known as electronically commutated motors (EC motors, ECM) are known synchronous motors. They are powered by a DC power source through a power system / integrated switching power converters. This energy source produces an electrical signal to operate the AC motor. This signal is a bidirectional current waveform has no limitation, instead of a sinusoidal waveform. additional electronic sensors and control the waveform and output the amplitude inverter.
Often the motor areas of BLDC motors are permanent magnet synchronous motors. However, they can be induced or switched reluctance. A BLDC motor can be defined as a stepping motor. However, be used as a rule, step motors in engines arrested regularly set his rotors angular positions. BLDC motors with a few important performance parameters are constant Km and Kv motor. In SI units, these constants are numerically equivalent.
Direct drive motors are the engines that lead without reduction (such as gears) engine power. The advantages of this include higher efficiency, because the power is not wasted by friction (chain, gear or belt). In addition, direct drive motors are quieter because they are simple devices and the dynamic least parts. Therefore, in general, the overall sound generating system is much lower.
In addition, direct drive motors have a longer life. With less vibration parts, they are much less likely to fail. Usually the motors are also other problems caused by stress or aging of components (such as stretched belt). These motors generate a substantial torque on a little diet.
Types of direct drive motors have a faster and more accurate positioning. The low inertia and high torque facilitates times faster for the positioning of the permanent magnet synchronous servomotors. In addition, feedback from the sensors are attached directly to the rotating part, which enables accurate detection of angular positions. Better yet, in these motors, hysteresis and elasticity towers are eliminated not use because of ballscrews or the transmission.
The main disadvantage of these systems is that they require special properties. Generally, engines are built to produce maximum torque at a fast speed is always 3000 or 1500 rpm. This is useful for many applications, such as electric fans. However, other devices may require fairly high torque at extremely slow speeds. Phonograph record player is a good example of what they need accurate and constant 45 rpm 33.3 rpm.
