DC Brush Motor:
Brushes and commutators
Unlike other types of motors, such as brushless DC motors and AC induction motors, BDC motors do not require a controller to switch the direction of current in the electrode winding, but instead complete the commutation of the BDC motor winding mechanically. There is a segmented copper sleeve installed on the shaft of the BDC motor, called a commutator. As the motor rotates, the carbon brush will slide along the commutator and make contact with different segments of the commutator. These segments are connected to different rotor windings, so when energized through the motor's brushes, a dynamic magnetic field is generated inside the motor. It is important to note that the brush and commutator are the most easily worn parts in BDC motors due to their relative sliding.
Permanent magnet
Permanent Magnet Brushed DC (PMDC) motors are the most common BDC motors in the world. This type of motor uses permanent magnets to generate a stator magnetic field. PMDC motors are typically used in applications including fractional horsepower motors, as permanent magnets are more cost-effective than winding stators. The disadvantage of PMDC motors is that the magnetic properties of permanent magnets gradually decline over time. Some PMDC motors also have windings wound around their permanent magnets to prevent magnetic loss. The linearity of the performance curve (voltage speed relationship curve) of PMDC motors is very good. There is a linear relationship between current and torque. Due to the constant stator magnetic field, this type of motor responds very quickly to voltage changes.
Samples
DC Motor Characteristic
1.Compared with the LDO of linear regulators, high efficiency is a significant advantage of DCDC. Usually, the efficiency is above 70%, and the high efficiency can reach over 95%.
2. Adapt to a wide voltage range.
DC Motor Classification
In switching DC-DC converters, transistors operate as switches, which means they consume much less power than transistors operating as current dependent sources. When a transistor conducts high current, its voltage drop is very low, while when a transistor conducts high voltage drop, its current is almost zero. Therefore, the switching mode converter has low conduction loss and high efficiency, usually above 80% or 90%. But at high frequencies, switching losses can reduce efficiency, and the higher the switching frequency, the higher the power.
