Differences Between Brushless and Brushed DC Motors
Brushless Motors vs Brushed Motors
For several years now, we’ve been seeing brushless motor dominating advance power tool industry. Does it really make difference to use brushless over brush motor? Yes, absolutely. There are significant difference between them.
Let’s look at the basics of DC motors. DC motors are all about magnets and electromagnetism. Oppositely charged magnets attract each other. The main idea behind DC motor is to keep the opposite charge of the rotating component attracted towards non-moving magnets (the stator) in front of it so it generates constant pull. This forward pull movement is produced by the physical behavior of electromagnetism.
Principles of Brushless Motors:
It is based on the principle that when a current-carrying conductor is placed in a magnetic field, it experiences a mechanical force whose direction is given by Fleming’s Left-hand rule and whose magnitude is given by
Force,F = B I l newton
Where B is the magnetic field in weber/m2.
I is the current in amperes and
l is the length of the coil in meter.
The force, current and the magnetic field are all in different directions.
Construction Differences Between Brushed vs. Brushless Motors:
Brushes inside electric motors are used to deliver current to the motor windings through commutator contacts. The brushless motor does not have current carrying commutators. The field inside a brushless motor is switched via an amplifier triggered by a commutating device, such as an optical encoder.
A brushed DC motor uses a configuration of wound wire coils, the armature, acting as a two-pole electromagnet. The current’s directionality is reversed twice per cycle by the commutator, a mechanical rotary switch. This facilitates the flow of the current through the armature; thus, the electromagnet’s poles pull and push against the permanent magnets along the outside of the motor. The commutator then reverses the polarity of the armature’s electromagnet as its poles cross the permanent magnets’ poles.
A brushless motor, by contrast, utilizes a permanent magnet as its external rotor. In addition, it uses three phases of driving coils and a specialized sensor that tracks rotor position. As the sensor tracks the rotor position, it sends out reference signals to the controller. The controller, in turn, activates the coils in a structured way – one phase after the other.
Brushless DC Motors by Elinco
Elinco JPC offers multiple brushless DC motors. We offer standard products as well as full engineering and manufacturing capabilities, to help fit any of your product needs. Contact Elinco today to get started on your project!