Brushed Motors Commonly Used in Consumer Servos

For mass production supporting of consumer-grade micro servos, standardized brushed motors serve as the core power source for most light-load models, educational robots and small automated swing mechanisms. Compared with custom motors, standard models feature mature structures, simple control and high mass production stability, making them the mainstream solution with the best cost performance for servo manufacturers at present. The N20, N30 and 130 brushed motors mass-produced by Huajuntong cover the matching requirements of all conventional micro servo series of 9g, 17g and 25g‑30g on the market. Differences in dimension, speed and original torque of various models directly determine the load capacity and applicable scenarios of finished servos.

The 9g micro servo is the most widely used basic model currently. With extremely compact internal space, it can only be fitted with the N20 micro brushed motor. Compact and lightweight, this motor works under conventional servo voltage of 4.8V‑7.4V. It delivers high native speed and low inherent torque, and relies entirely on the multi-stage gear reduction structure inside the servo for torque amplification. After full transmission matching, the finished 9g servo can achieve an output torque of 1.2‑1.8 kg·cm, which is sufficient for working conditions such as aircraft model wing swing, fine adjustment of small robot joints and light-load angular positioning. Leveraging the fast start-stop response and sensitive forward/reverse switching of brushed motors, the servo maintains stable angle tracking accuracy. Combined with simple drive circuits and no need for complex algorithm control, it is ideal for mass production of consumer-grade products and represents a mature and widely adopted combination in the industry.

For 17g servos requiring higher load capacity and having more structural space, the mainstream industry supporting solution is the N30 brushed motor. Compared with the N20, the N30 motor boasts greater inherent torque reserve and stronger load stability, capable of handling frequent forward and reverse rotation as well as minor overload conditions. After torque amplification by the standard reduction gear set of the servo, the finished 17g servo can reach an output torque of 2.5‑3.5 kg·cm. It is suitable for medium-load applications including gripping by small mechanical claws, steering and gear shifting of RC car wheels, and moving joints of desktop bionic robots. This motor features mature winding parameters. Lead wires and shaft length specifications can be slightly adjusted according to customers’ gearbox reduction ratios, balancing mass-production versatility and custom project adaptability with a higher fault tolerance rate.

For 25g‑30g medium-sized servos, the equipment has higher requirements for torque and resistance capability. Since the power reserve of N20 and N30 cannot meet such demands, the 130 brushed motor is generally selected as the core power source. The 130 motor features a larger structure, sufficient stall torque and high power margin. After being assembled into medium servos and matched with reduction assemblies, the finished servo can deliver an output torque of 4‑6 kg·cm. It can stably support working conditions such as trolley steering mechanisms, automatic baffle opening and closing of small equipment, and mechanical swing under moderate loads, and is not prone to jamming or stalling under slight external resistance. As a classic universal model, the 130 motor has mature manufacturing processes, good batch consistency and stable long-term supply, making it ideal for regular mass production supporting of medium and large servos.

From the perspective of actual working conditions, all three motors are designed for intermittent operation, perfectly matching the working logic of servos for short-time swing, positioning and standby, and avoiding the drawback that brushed motors are not suitable for long-term continuous full-load operation. The overall selection logic is clear: choose N20 for light-load micro positioning, N30 for medium-load precise movements, and 130 for heavy-load anti-resistance swing.

Huajuntong’s three standard brushed motors dedicated for servos are mass-produced with mature molds, featuring stable parameters and controllable costs. Sample testing is available, and minor adjustments such as lead wires, shaft types and shaft lengths are supported to fully meet the R&D and mass production requirements of various micro servos.