When it comes to electric motors, there are two types that are commonly used: core motors, or brushed motors, and coreless motors which are brushless. Both types have their advantages and disadvantages, and it’s often a matter of personal preference which is used in a given application.
How Do Coreless DC Motors Work
One single step to understanding why coreless DC motors are so unusual is to match them to a regular DC motor and then note the differences. A conventional brushed DC motor possesses an inner core made from iron, with coils that are weaved tightly around this inner core, with the rotor made of dense iron layers. A coreless DC motor will not have this inner iron core component, hence its name – coreless.
This unique design does not suggest that a coreless DC motor is of lower quality when contrasted to DC motors with their inner iron cores. The contemporary coil design has been chosen to improve the rotor’s mechanical strength.
Typically, a DC motor will be expected to manage quite large torque levels. With the absence of a core, an epoxy substance is appended to the rotors within coreless DC motors. What this epoxy substance does is strengthen the rotor coils so they cannot be readily damaged.
Coreless DC Motor Types
Based on construction, coreless DC motors are classified into two types:
- Single-phase induction motor (SI mono-rotor) – In this case, the rotor is a single-phase induction type, which means the rotor has one winding and is connected to one phase of the supply voltage.
- Three-phase induction motor (3-phase bi-rotor) – In this case, the rotor has three windings connected in Y or Delta connection, meaning both ends of the rotor are connected to separate phases of the supply voltage.
Cored vs Coreless DC Motor
The main difference between cored and coreless DC motors is the absence of a core in the latter type. As there is no core, these motors are compact in size compared to traditional DC motors with iron-cored rotors. A coreless DC motor has no iron core making it ideal for applications where an iron-cored rotor would be too heavy and bulky.
The Applications of Coreless Motors
Single-phase induction motor (SI mono-rotor): This is the most widely used type of coreless motor. It is suitable for low-torque and low-speed applications. Three-phase induction motor (3-phase bi-rotor): As the name suggests, it is suitable for applications where higher speed is required along with higher starting torque. It is used in fans, pumps, conveyor belts, textile machinery, and other applications.
Other applications of coreless DC motors include ink-jet printers, food processors, and hoisting equipment. As these coreless DC motors are lightweight and suitable for high-speed applications, they are also used in computer equipment, clocks, and some medical instruments.
The various advantages that coreless DC motors produce make it a recommended option when accuracy, durability, and performance are necessary requirements, regardless of the industry application.
Practical applications of coreless DC motors within the healthcare industry, for example, include: powering dialysis pumps, surgery equipment and tools, CPAP machines, and ambulatory immersion pumps.
Coreless DC motors are used broadly in medical applications, including insulin pumps, prosthetics, laboratory equipment, and X-ray machines. Coreless DC motors manage fast and powerful movements, which makes them suitable for robotic applications.
Advantages of Using Coreless Motors
There are many benefits and advantages to using a coreless DC motor over a cored DC motor. One of the advantages of using a coreless motor is the fact that it has such a wide variety of applications, particularly in the medical industry. Telco creates motors with efficiency and durability that provide reliable motors every time.
The advantages of coreless DC motors essentially originate from their physical attributes that provide the following:
High efficiency with a smaller design
An ironless DC motor has an effective motor that is much lighter than others on the market. Coreless DC motors normally have a limited loss of current, making them overall more efficient than DC-cored types.
Drawing lower current
A coreless DC current will not draw as much current as other motors. This ensures that the battery will last longer than expected.
Functional optimization
When seeking a DC motor to handle quick acceleration and deceleration, the coreless DC motor configuration is a suitable choice. It manages these circumstances adequately since it possesses a lighter rotor that does not produce as much inertia as other DC motors.
Cogging will not occur
A coreless DC motor never provides a scenario where the stator magnetic circuit and the rotor become misaligned. Unlike other DC motors, cogging will no longer occur, and the motor will operate smoothly.
Durability and safety
Because there is no inner iron core, there will be a reduced chance of sparks and arcing that usually occurs between a cored DC motor’s brush and commutator. A coreless DC motor typically lasts longer and with significantly reduced electromagnetic interference.
Effortless control
End-users of coreless DC motors appreciate the easy control that this motor type provides and its manageable speed.
Drawbacks of a Coreless Motor
Naturally, there are a few drawbacks that will need to be managed when using coreless DC motors. A coreless DC electric motor requires external cooling, so a DC motor’s encasing must have sufficient thermal conductivity. The importance of this drawback is more acute if the motor is used for quick acceleration and deceleration in rapid succession.
Because coreless DC motors tend to overheat with increased usage, the motor does tend to require more maintenance as the bonding windings’ will lose their effectiveness. Therefore, coreless DC motors are unsuitable for extended periods of use than a cored DC motor can manage.
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Telco is proud to carry some of the best coreless motors currently available in the United States. We take our craftsmanship seriously which is something that our customers appreciate as that dedication results in a truly superior product.
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