Coreless DC Motors: A Guide to Choosing the Right One

DC Coreless motors contain distinctive structures and provide many benefits compared to conventional iron-core DC motors. Definition, classification, working principles, benefits, applications etc. are discussed in detail in this article.

What is a DC Coreless Motor?

A DC coreless motor does not contain a laminated iron core in the rotor, while a traditional brushed DC electric motor contains an iron-made inner core.

Below is a diagram of Assunmotor’s coreless brushed DC motor.

Below is a diagram of Assunmotor’s coreless brushless electric DC motor.

Classification of DC Coreless Motor:

· Single-phase induction motor: The rotor has one winding and it is attached to one phase of the supply voltage.

· Three-phase induction motor: The rotor has three windings attached to the Y or Delta connection.

Working principles of DC Coreless Motor

An epoxy material is attached to the rotor in a DC coreless motor due to the absence of a core.  The epoxy material is attached to harden the rotor coils so that it cannot be damaged.  The stator is made from earth magnets and stays on the inner side of the coreless motor. To regulate the current in the rotor windings that generate constant rotation, brushes and commutators are used.

The working principle of a DC coreless motor is the same as a traditional DC motor. If any current moves through a coil in a magnetic core field, the electromagnetic coil experiences a force that creates rotation.

Advantages

1. Less weight: DC coreless motors have less weight than conventional DC motors. Due to less weight, the DC coreless motor is perfect for portable devices and robots.
2. Compressed: DC coreless motors are smaller in size than conventional DC motors. Due to the small size, these are good for tiny accessories and toys.
3. Less Noise: DC coreless motors create less noise than conventional DC motors. Due to less noise, DC coreless motors are popular for medical devices and office electrical equipment.
4. Safe and Secure: DC coreless motors are very safe and secure and can last many years with appropriate maintenance.
5. Improved efficiency: Since the DC coreless motor does not contain iron, it has fewer iron losses and more efficiency than the iron-core DC motor.
6. Less sparking: Due to the coreless design of the motor, winding inductance can be reduced, which causes the minimization of sparks between the brushes and commutator.
7. Low current consumption: The current consumption of a DC coreless motor is low because it does not draw as much current as other motors. So the battery can be operated for a long time.
8. Fast operation: For quick acceleration and deceleration, the DC coreless motor is an appropriate choice. Due to the lightweight rotor, much inertia cannot be generated in the DC coreless motor.
9. Smooth Operation: The stator magnetic circuit and the rotor are aligned with each other in an appropriate way. Due to the proper alignment of the stator magnetic circuit and rotor, the DC coreless motor can be operated smoothly.

Applications

Single-phase induction motor application: The DC coreless motor is a perfect choice for the application of a single-phase induction motor. It is quite appropriate for low-torque and low-speed uses. With the requirements of higher speed and starting torque for different applications, a three-phase induction motor is an excellent choice. It can be used in pumps, fans, textile machinery, etc.

Lightweight and high-speed applications: Since coreless DC motors are lightweight, they are very suitable for high-speed applications such as computer equipment, clocks, medical instruments, and ink-jet printers, etc.

Medical device applications: Because of high reliability, low noise, and accurate control, coreless DC motors are widely used in medical applications such as insulin pumps, x-ray machines, laboratory equipment, surgical tools, ventilators, etc. In the healthcare industry, coreless DC motors are used in dialysis pumps, surgery equipment and tools, and ambulatory immersion pumps.

Small-scale aircraft applications: For small-scale aircraft such as drones and model planes, coreless DC motors are suitable for their high power-to-weight ratio and high speed. Coreless DC motors can be operated effectively by battery power with less maintenance needs.

Robotics applications: Since coreless DC motors are able to provide quick and precise motions, these are good for robotic arms, joints, and wheels. They have enough capacity to manage continuous start-stop cycles and variable loads without overheating or losing performance.

Actuators: For various types of actuators, such as linear actuators, rotary actuators, and pneumatic actuators, coreless DC motors are the perfect choice.

Important Features for the Selection of a DC Coreless Motor

Consideration should be given to the following factors for choosing a DC coreless motor.

Size and Weight: The small size and lightweight DC coreless motors are perfect for applications where size and weight are important concerns.

Speed and Torque: Speed and torque are important criteria to measure the performance of a DC coreless motor. The speed and torque of a coreless DC motor rely on the voltage of the motor terminals and the load of the motor shaft.
Efficiency and Power Consumption: The model of winding, the type of magnet, and the brush material determine the efficiency and power consumption of a DC coreless motor. The right coreless DC motor should be chosen so that it has high efficiency and low power consumption to preserve energy and increase the battery life.

Noise and Vibration: Noise and vibration can affect the performance of a coreless DC motor. Noise can be created in a coreless DC motor because of the friction and spark. Vibration can be generated due to imbalance, misalignment, or resonance. The features of coreless DC motor elements, such as bearings, brushes, and commutators, play a vital role in the generation of noise and vibration. The right kind of coreless DC motor should be chosen so that the motor can operate smoothly with low noise and vibration.

Conclusion

DC coreless motors do not contain any iron core in the rotor. They have many benefits, such as less mass and inertia, improved efficiency, and less sparking than traditional iron-core DC motors. DC coreless motors are excellent for applications requiring high dynamics, accuracy, and efficiency.

If you need help choosing a suitable coreless DC motor for your project, contact us here. Or you could check our range of coreless brushless, brushed, and servo DC motors by clicking the button below.