A large amount of electricity and magnetism are generated during the operation of a DC brushless motor, but even so, its use is still safe, because the motor has a current limit during use, which prevents short circuit caused by excessive current. So how does the motor achieve its current limit?
1. The external inverter bridge of the DC brushless motor is grounded through a resistor Rs for current sampling, and the sampled voltage is input to the current detection comparator.
2. The inverting input terminal of the comparator is set with a reference voltage of 100mV as the current limit reference.
3. During the rise time of the sawtooth wave of the DC brushless motor, if the current is too large, the comparator flips over, resets the lower Rs trigger, and turns off the drive output. The purpose of this is to limit the current to continue to increase.
4. At the falling time of the sawtooth wave, set the trigger again to turn on the drive output.
The current of the brushless DC motor will not increase without limit. On the contrary, to a certain extent, the current will be limited. In this way, the operator will be safer when using the motor. In this way, the safety of the motor can also be protected and reduced. The occurrence of dangerous failures.
