The maximum voltage capabilities of Brush DC and Brushless DC (BLDC) motors differ significantly due to the particular design and operating concepts of each motor technology. Physical brushes in Brush DC motors conduct the electrical current, which naturally limits their maximum voltage capacity. The electronic commutation system of BLDC motors, on the other hand, enables them to manage higher voltages with greater efficiency. Let’s explore these differences in more detail.
Understanding the Voltage Range of Brush DC Motors, #
Typically, the various winding configurations of Brush DC motors are optimized to run close to the recommended maximum speed of around 10,000 RPM at the nominal voltage, even under no load conditions. Referring to the Portescap 16DCT Brush DC motor datasheet shown in Figure 1, for example, we can see a representation of the recommended maximum supply voltage for a typical Brush DC motor.
For the motor to have a reasonable lifespan, this operational restriction on the maximum continuous speed is essential. It is interesting to note that the mechanical commutation system’s wear and tear increases with the number of rotations and, consequently, with the motor’s speed. Therefore, exceeding the nominal voltage level is discouraged in applications where a long motor lifespan is expected. However, there are some exceptions, such as in disposable applications that require high speeds for brief periods of time or in industrial power tools that might need brief periods of high peak speeds under no load conditions.
Voltage Capacity of Brushless DC Motors: #
BLDC motors, in contrast to Brush DC motors, rely on electronic commutation, removing the mechanical wear connected with conventional brushes. As a result, rather than the commutation mechanism, the maximum speed of a BLDC motor is primarily constrained by components like the rotor assembly and bearings. As shown in Figure 2, BLDC motors have a much higher maximum speed capacity than Brush DC motors.
To avoid excessive vibration at high speeds, the 12v bldc motor rotor assembly must be properly balanced. The maximum speed that can be achieved also depends on the type and size of the bearings supporting the rotor assembly, as well as on lubrication, sealing, and mounting distance. Moreover, in motors with integrated electronics, the PCB integrated within the motor may limit the maximum supply voltage.
It’s important to remember that when running at nominal voltage, BLDC motors frequently run at speeds less than their maximum advised limit. The motor speed can be raised toward the advised maximum speed by increasing the supply voltage, as shown in Figure 2. To prevent motor overheating brought on by rising iron losses, it is crucial to take into account the lowered maximum continuous torque at higher speeds.
Seeking Expert Direction for Vehicle Operation
Our team of engineers is available to help you if you have questions about the safe operation of your motor or about choosing the right motor for your particular application needs. We can offer thorough assistance in deciding on the appropriate limits for your application, including speed, torque, temperature, and lifespan. Please get in touch with us to start a conversation about your motor requirements!
In conclusion, the different maximum voltage capacities of Brush DC and BLDC motors highlight the importance of knowing the subtleties of each motor type to make wise decisions about motor choice for various applications. You can increase the efficiency and longevity of your motor – driven systems by understanding the operational constraints and performance characteristics of these motors.
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