What are differences between BLDC motor and AC motor
The brushless motor system consists of a motor and a brushless motor controller. Since the BLDC motor runs in a self-controlled manner, it has no additional starting winding to the rotor as the asynchronous motor. Even if the load changes suddenly, there will be no oscillation or out-of-step.
AC motor is a device that converts AC electric energy to mechanical energy. It mainly comprises electromagnet winding or distributed stator winding and a rotating armature or rotor. There are synchronous AC motor and AC induction motor.
Compared with AC motors, the brushless motor has the following advantages:
- High torque at low speed. At low speeds, the torque of the AC motor is low, while the torque of the BLDC motor is much higher.
- Wide speed range. Generally, the speed range of the BLDC motor is 50-3000RPM, AC motor is 150-1350RPM. Moreover, the BLDC motor speed could be adjusted evenly and smoothly even under heavy load.
- High efficiency. The efficiency of the brushless motor is more than 75%, while the efficiency of the AC motor is only 30~40%. Therefore, brushless motor is more energy-saving, which is in line with the global trend of energy conservation and environmental protection
- Quick response. Similar to car starting, a car with superior performance accelerates quickly, and so does a brushless motor.
- Compact structure. At the same power, brushless motors are smaller than AC motors, so they require less raw materials and save more cost.
- DC or AC power input. If the BLDC motor driver is connected to AC, the driver converts AC to DC for the motor to work. If DC is input, the drive does not need to convert. Compared with AC, DC has the advantages of convenience and safety. For example, for AGV equipment, high torque brushless motor is widely used as it can be input DC. Because it’s safer, a brushless DC motor is often used for entertainment equipment.
Generally speaking, the selection of motors is based on all aspects of specific applications. Users are increasingly leaning towards DC motors, especially BLDC motors.
