As the name suggests, a brushless DC motor has no brushes! Its no-load resistance mainly comes from the rotational contact points between the rotor and stator. Therefore, most brushless motors use ball bearings at both ends of the rotor to reduce friction, thus eliminating excessive frictional resistance and heat. They possess extremely high efficiency (80%-90% or more) and high speed, making them widely used in transmission equipment across various industries, providing a highly efficient, energy-saving, and environmentally friendly power source for various devices.
The brushless DC motor uses a 3-phase, 6-step control, so the 3 Hall effect sensors correspond to 3 motor wires and 6 output states. There are 36 possible connections, of which 6 will allow the brushless motor to operate at normal speed. Of these 6 connections for the 120-degree controller, 3 are for forward rotation and 3 are for reverse rotation. The 60-degree controller has 4 connections that will allow the brushless DC motor to operate at normal speed, two for forward rotation and two for reverse rotation. Therefore, we only need to adjust the 120-degree controller a maximum of 7 times, or the 60-degree controller a maximum of 13 times, to solve the problem.
A quick method for matching the phase of a brushless DC motor with its controller requires preparatory work before commissioning.
Step 1: Use a Hall effect sensor to check if the motor's Hall effect sensors are functioning correctly to ensure successful debugging on the first attempt. (Do not use a multimeter, as it will not only be inaccurate but may also damage the Hall effect sensors.)
The second step is to ensure that the motor's speed and the controller's speed are matched (60 degrees and 120 degrees are different and cannot be substituted for each other) to ensure that the effort is not in vain.
Step 3: After the controller is powered on, both the rotor and the Hall sensor will output 5 volts. At this point, you can connect the motor wires and test run it.
First, we need to get the brushless DC motor running normally. This is usually done by directly plugging in the Hall sensor connector and adjusting the motor wiring. Below are six common wiring methods for brushless DC motors. For ease of memorization, the controller is usually placed on top and the motor on the bottom; we can remember it like this:
1. Color to color connection
2. Blue to blue, the other two colors swapped.
3. Yellow to yellow, the other two colors swapped.
4. Green with green, the other two colors swapped.
5. Pair blue on top with yellow on the bottom, and swap the other two colors.
6. Yellow on top, blue on the bottom, and the other two colors swapped.
2. Phase mismatch: A brushless DC motor will exhibit four behaviors: not turning, high noise at slow speed, high noise at rapid speed, and normal operation. During normal operation, the motor noise is very low, and the speed is moderate. When applying current, apply only a very small amount and listen to the motor's sound; if the motor can move, it's fine. Suddenly applying too large a stall current may damage the controller.
If none of the above 6 methods work, then try the following methods.
Third, take out the wire in the middle of the Hall connector and swap it with one of the wires on the side. Repeat the above 6 steps. There will definitely be a connection method that will allow the brushless motor to run normally.
The above connection method will allow the brushless DC motor to run normally, but it doesn't guarantee forward rotation. Remember, a brushless motor can rotate in both directions, including forward rotation. To make it rotate in the forward direction, swap the motor wires (phases A and B) and the Hall effect sensor wires (phases A and C). (That is, keep the middle wire in the Hall effect sensor connector in place and swap the two ends; the motor will immediately rotate in the forward direction). After the above adjustments, the matching between the controller and the motor is complete.
