Detection of motor rotation with Hall elements
A brushless motor, the mainstream at present, has achieved downsizing and loss reduction by incorporating Hall elements, providing the highly accurate rotation control.
This is the most popular method for small-sized motors. We introduce the most typical hall motor applications here.
Advantages of using Hall elements
● High durability due to non-contact detection
● Highly resistant to contamination such as dust, dirt, or oil, because of detection of magnetism
● Downsizing, weight reduction, and loss reduction are possible.
A Hall effect IC can obtain the analog output corresponding to the strength of the magnetic field and uses these characteristics to detect the rotor position.
If one or multiple Hall elements are allocated in parallel on the stator side opposite to the magnet pole of the motor rotor, the rotor position can be detected from the magnet allocation, enabling the detection of the rotation.
Here, the typical example in which three Hall elements are placed at locations offset by 60 degrees each other on a 4-pole rotor and the index detection example.
A 4-pole rotor and three Hall elements are used to detect the rotation.
● A maintenance-free motor can be implemented.
● Application-specific design is possible.
● Stable activation and low vibration allow a quiet operation.