Applications of Brushed Coreless DC Motors
The combination of zero cogging, low inertia, and compact size makes brushed coreless DC motors a natural fit for applications where smooth motion and fast response matter more than raw continuous power output.
Some of the industries where Assun motors are commonly specified:
- Medical Devices: Infusion pumps, surgical handpieces, diagnostic laboratory equipment, and insulin delivery systems all benefit from the smooth, controllable motion that a coreless design provides. The absence of cogging torque is particularly important in flow-control applications, where stepwise motion causes dosing inaccuracies.
- Robotics and Automation: Brushed coreless motors are used in robotic joint mechanisms, end-effector drives, and lightweight manipulator arms where rapid directional changes are part of normal operation. The low rotational inertia reduces settling time and improves positional accuracy.
- Precision Instruments and Optical Equipment: Motorised stages, lens drives, filter wheels, and scanning mirror systems require smooth, cogging-free rotation. A coreless motor paired with an encoder can deliver the positioning resolution these systems demand.
- Handheld and Portable Devices: Weight and size are dominant constraints. The coreless design's high power-to-weight ratio makes it the preferred choice over a comparable iron-core motor where every gram matters.
- Industrial and Lab Automation: Pick-and-place systems, dispensing heads, and pipetting robots require fast, repeatable actuation another application where low inertia and cogging-free behaviour translate directly into cycle time and throughput improvements.
Pairing Your Motor with Gearboxes, Encoders, and Controllers
A brushed coreless motor is rarely used in isolation. Most applications require additional components to form a complete drive system.
- Planetary Gearboxes: Assun's planetary gearbox range available in Regular, Precision, and High Performance series mounts directly to our brushed motor shafts. They reduce speed and multiply torque, extending the application range of the motor into higher-load scenarios.
- Motor Encoders: For applications requiring position or speed feedback, Assun offers incremental and absolute encoders in optical and electromagnetic variants, configured to fit directly to our motor range.
- Servo Controllers: If your application requires closed-loop position or speed control, Assun's DC integrated servo motors and servo motor controllers provide a matched drive system eliminating the integration risk of combining components from separate suppliers.
All accessories are available to order through the online shop or via our US sales team for custom configurations and volume pricing.
FAQs
Q1. What is a brushed coreless DC motor?
A brushed coreless DC motor is a type of DC motor where the rotor has no iron core instead, the copper windings form a self-supporting hollow cylinder. This eliminates magnetic cogging (the stepping sensation in iron-core motors), reduces rotor inertia significantly, and allows for faster acceleration and deceleration. Current is transferred to the rotor via carbon or precious metal brushes and a commutator, making the motor simple to drive and compatible with standard DC power supplies.
Q2. What is the difference between a coreless motor and a standard DC motor?
A standard DC motor has an iron core in the rotor that helps concentrate the magnetic field. The iron produces cogging torque a stepwise resistance as the motor turns and adds significant rotational inertia. A coreless motor removes the iron core entirely, eliminating cogging and reducing inertia dramatically. The result is smoother rotation, faster dynamic response, and better performance at low speeds. The tradeoff is that coreless motors generally have lower continuous torque capacity than iron-core motors of the same diameter.
Q3. What is the difference between precious metal and graphite commutators?
Precious metal (typically silver alloy) commutators have low contact resistance and minimal brush wear suited for low-current, precision applications like medical devices and instrumentation. Graphite commutators have a larger contact surface area and stronger contact force, making them more robust under higher currents, mechanical vibration, and shock loads better for industrial automation and robotics. Both types are available in Assun's brushed coreless motor range.
Q4. Can a brushed DC motor be used without a controller?
Yes. A brushed DC motor can be run directly from a DC power supply applying voltage produces rotation, and reversing polarity reverses direction. Speed can be controlled by varying the supply voltage or using a simple PWM circuit. For applications requiring closed-loop position or speed control, a servo controller can be added. Assun's brushed coreless motors are compatible with both open-loop direct drive and closed-loop servo control configurations.
Q5. What diameter range do Assun's brushed coreless motors come in?
Assun's brushed coreless DC motor range covers diameters from 8mm to 52mm (28mm and 32mm included). Within each diameter, multiple body lengths are available, giving engineers flexibility in matching the motor to their mechanical envelope. All models are available for direct purchase through the Assun online shop.
Q6. What industries use brushed coreless DC motors?
Brushed coreless DC motors are commonly used in medical devices (infusion pumps, surgical handpieces, diagnostic instruments), precision robotics and automation, optical and scientific instruments, handheld and portable tools, and consumer electronics requiring smooth, compact motor drives. Their zero-cogging behavior and fast transient response make them preferred in any application where smooth motion across a wide speed range is required.
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