In this section, we will explore the operation of brushed motors and BLDC (Brushless Direct Current) motors, highlighting their differences and advantages in various applications, such as air conditioner condenser fan units.
Conventional Brushed Motors
On-screen, we observe a traditional motor equipped with brushes. In this design:
Role of Brushes and Rotor:
- The brushes and rotor contacts are crucial for altering the current’s direction, which changes the polarity of the magnetic field generated in the coils.
While effective, these motors have several drawbacks:
- Shorter lifespan due to brush wear.
- Lower energy efficiency.
- Higher noise levels during operation.
- Frequent maintenance requirements.
- Limited speed range.
BLDC Motors: A Modern and Efficient Solution
BLDC motors eliminate brushes and rely on an electronic module to control current flow and polarity changes using six internal transistors.
Basic Operation:
- Each coil in a BLDC motor is connected to two transistors that manage current flow in both directions.
- These transistors act as switches:
- When activated for longer periods, the motor speeds up.
- When rapidly deactivated or blocked, the motor slows down.
Technological Advancements of BLDC Motors:
- Precise speed control: Efficient adjustments via the electronic controller.
- Extended lifespan: No brushes mean no mechanical wear.
- Efficiency and versatility: Suitable for a wide range of applications.
Interaction Between Rotor and Coils in BLDC Motors
The rotor in a BLDC motor is equipped with permanent magnets that create a magnetic field. This field interacts with the one generated by the coils, producing smooth and controlled motion.
Operation Sequence:
- Permanent Magnets on the Rotor:
- For instance, if the rotor has a negative polarity near coil 1, the controller supplies current to this coil, creating a positive magnetic field.
- This field attracts the rotor toward the coil.
- Attraction Between Coils:
- When the rotor aligns with coil 1, the controller redirects current to coil 2, generating a new positive magnetic field that attracts the rotor further.
- Continuous Cycle:
- This process repeats with subsequent coils (e.g., coil 3), ensuring smooth and efficient motion.
Result:
This cycle of attraction, managed by the electronic controller, guarantees the BLDC motor’s continuous, precise, and efficient operation.
Applications of BLDC Motors
BLDC motors are becoming the preferred choice across industries due to their numerous advantages. A notable example is their use in air conditioner condenser fan units, where they offer:
- Greater durability.
- Quieter operation.
- Superior energy efficiency.
