Differences Between 12mm Brushed and Brushless Geared Motors
In the field of micro‑transmission with an ultra‑small 12 mm diameter, the two most widely mass‑produced and highly adaptable power solutions are the N20 iron‑core brushed planetary geared motor and the 12 mm coreless brushless planetary geared motor. They share the same outer diameter and are compatible with the identical 12 mm planetary gearbox. Their overall mounting dimensions are interchangeable for many mechanical designs. However, they differ significantly in internal structure, operating characteristics, service life, application cost and applicable scenarios.
Many R&D engineers tend to focus only on dimensional and torque parameters when selecting motors for micro‑precision equipment, while overlooking essential differences in motor core structures. This may result in unsatisfactory product performance in terms of battery life, noise level, service life and after‑sales reliability. This article objectively compares the application differences between the two 12 mm micro planetary geared motors from the perspectives of hardware structure, actual working conditions and mass‑production implementation.
I. Core Structural Differences (Essential Distinctions)
1. N20 Iron‑core Brushed Planetary Geared Motor
It takes the traditional N20 iron‑core brushed motor as the power unit. Adopting iron‑core winding and carbon‑brush mechanical commutation inside, it forms a geared assembly matched with a standard 12 mm planetary gearbox. As a micro‑geared motor solution with the longest‑standing standardization and mass‑production history in the industry, it features mature structural processes, fully‑general‑purpose mould‑made components and high assembly tolerance. It is suitable for most civil‑use micro light‑load equipment.
2. 12mm Coreless Brushless Planetary Geared Motor
It adopts a coreless brushless motor core with iron‑core‑free design and no physical carbon‑brush commutation. Electronic commutation is realized by circuit board Hall sensor control, paired with the same 12 mm planetary gearbox. Featuring more precise internal structure and lower running resistance, it represents a high‑end micro power solution within the 12 mm size range, with a core hardware architecture completely different from conventional brushed motors.
II. Comparison of Key Performance Parameters (Under Same‑size and same‑gear‑ratio Conditions)
Comparison Item | N20 Brushed Planetary Geared Motor | 12mm Coreless Brushless Planetary Geared Motor |
Motor Core Structure | Iron‑core winding, mechanical commutation with carbon brushes | Coreless iron‑free design, electronic commutation |
Operating Noise | Normal operation with slight friction noise from carbon brushes | Extremely low noise with smoother operation |
Service Life | 300‑500 hours under normal intermittent operating conditions | Capable of continuous operation, service life several times longer than brushed models |
Start‑Stop Smoothness | Slight electromagnetic stalling, relatively large start‑stop inertia | No hysteresis, extremely smooth start‑stop without jitter |
Power Consumption Performance | Moderate power consumption at no‑load and light‑load conditions | Higher energy efficiency under light‑load conditions, more power‑saving for equivalent battery life |
Control Mode | Direct power supply via positive and negative terminals, simple control | Requires matching driver board, supports precise speed regulation and positioning |
Mass Production Cost | Cost‑effective, suitable for large‑volume mass production | Relatively high cost, mostly applied in mid‑to‑high‑end precision products |
III. Differences in Actual Working Conditions (Key Points for R&D Selection)
1. Advantages and Application Scenarios of N20 Brushed Planetary Geared Motor
The biggest advantages of the N20 brushed solution are simple structure, easy control, controllable cost and universal accessories. No driving circuit is required; it runs once powered on. Forward‑reverse rotation can be realized simply by swapping electrodes, with very low requirements for mainboard design, which greatly reduces the difficulty of complete‑machine development.
It delivers fully adequate performance under intermittent start‑stop, short‑time operation and daily light‑load conditions, featuring extremely high mass‑production stability with almost no adaptation risks. It is widely used in mass‑consumer products such as small electric screwdrivers, micro‑motion structures of smart locks, small PTZ cameras, household small‑home‑appliance transmissions and micro opening‑closing mechanisms.
Its shortcomings are also obvious: carbon brushes are mechanically wearing parts. Long‑term continuous operation will cause wear and excessive temperature rise, and noise will gradually increase with service time. It is not suitable for long‑term non‑stop operation or high‑precision silent equipment.
2. Advantages and Application Scenarios of 12mm Coreless Brushless Planetary Geared Motor
The core highlights of the 12mm coreless brushless solution are wear‑free operation, high smoothness, low noise, long service life and zero hysteresis. Without carbon‑brush friction and iron‑core magnetic reluctance, the motor delivers highly responsive start‑stop performance with no jitter at low‑speed operation. It generates very low temperature rise and minimal performance degradation during long‑term continuous operation, maintaining consistent performance over its service life.
It also supports fine speed regulation, angular positioning and constant‑torque output, making it well‑suited for precision equipment with strict requirements on operating feel, noise, service life and stability. It is commonly applied in high‑end precision maintenance tools, medical micro‑transmission structures, premium wearable devices, precision smart PTZ cameras and micro‑devices requiring long‑term standby operation.
The limitation of this solution lies in the requirement for dedicated drive control and higher mainboard cost. The overall solution cost is much higher than that of brushed motors, so it is not suitable for low‑end mass‑production products pursuing extreme cost‑performance.