An Introduction to Mini DC Motor
A DC motor is a motor that converts direct current electrical power into mechanical power. The DC motor is generally composed of two parts: a stator and a rotor. While the stator consists of a main magnetic pole, frame, reversing pole, and brush device, the rotor is made up of an armature core, armature winding, commutator, shaft, fan, etc. The working principle of the DC motor is based on the principle that when a current-carrying conductor is placed in a magnetic field, it experiences mechanical force. There are two magnetic fields. One field is produced by the main magnetic poles, the other field is produced by an electrical current flowing in the motor winding. These two fields result in torque which rotates the rotor. As the rotor turns, the current in the winding is commutated to produce continuous torque output.
How to Choose the Right Voltage
Considering that modern electrical equipment consistently gets smaller, with its small size, the DC motor is required to provide high torque. That’s where mini DC motors come in. The speed of a DC motor (N) is equal to N = K (V – IaRa)/ ø where K is constant.
Thus, the speed of a DC motor can be controlled in three ways:
- By varying the flux, and by varying the current through the field winding
- By varying the armature voltage, and the armature resistance
- Through the supply voltage
A simple method to control the rotation speed of a DC motor is to control its supply voltage. Within reasonable range, the higher the voltage is, the higher the speed the motor tries to reach. Smaller DC motors are commonly used in the smart homes, intelligent robots, and automobile mechanisms such as electric car seats. If the DC motor is powered by batteries, it’s more suited for a lower operating voltage because multiple batteries won’t be required each time. For mini DC motors, the operating voltage ranges from 1.5 to 100V. Common motors include the mini DC motor 3V, mini motor DC 6V, and miniature 12V DC motor. At higher voltages, electronics are typically more efficient for running motors.
Mini DC Motor 3V
1. Rated Voltage: 3-12 V
2. No-load Speed: 11-3824 rpm
3. No-load Current: 30-40 mA
4. Rated Load Speed: 10-3229 rpm
5. Rated Load Current: 100 mA
The above is an example of a mini DC motor 3V. When combined with a planetary gearbox, the 3V DC motor can be used with an electric screwdriver to meet the design and functional requirements of the small size and large torque. Through the analysis of the functional requirements of the electric screwdriver, ZHAOWEI uses forward and reverse planetary gearboxes to adjust the torque of the electric screwdriver for tightening and loosening of the screw. In terms of safety, self-locking can be carried out by using a reduction gearbox and a screw rod. The internal self-locking structure will automatically open to avoid damage to the motor if it’s detected that the screwdriver is twisted manually.
1. Rated Voltage: 3-12 V
2. No-load Speed: 19-4630 rpm
3. No-load Current: 90-100 mA
4. Rated Load Speed: 15-3361 rpm
5. Rated Load Current: 155-160 mA
The above is the example of a mini motor DC 6V. When combined with a planetary gearbox, the 6V brushless DC motor can be used with a hair curler which protects hair while curling. The gearbox uses a brushless DC motor and a helical tooth design mechanism to achieve self-locking. It solves the issue of retracting the rotating mechanism and improves the service life of the product when the hair has curled to reach a specific torque.
Miniature 12V DC Motor
1. Rated Voltage: 3-24 V
2. No-load Speed: 20-4318 rpm
3. No-load Current: 60-80 mA
4. Rated Load Speed: 18-3625 rpm
5. Rated Load Current: 215-220 mA
The above is an example of a miniature 12V DC motor. When combined with a planetary gearbox, the 12V brushless DC motor can be used with robot joints. For quick response and interaction during communication, the DC gear motor is used to drive the joints of the robot, which require a large power to mass ratio and torque to inertia ratio, high starting torque, low inertia, and a wide and smooth speed regulation range. In particular, the end effector (gripper) of the robot should use a joint motor with a small volume and mass and a large short-term overload capability. Equipping the joints with a ZHAOWEI planetary gear motor can greatly improve the quality and efficiency of the robot.
ZHAOWEI Machinery & Electronics Co., Ltd is committed to providing gear motor development and manufacturing drive systems for motorized shelf lifts with customized technical parameters. These parameters are:
Diameter: 3.4mm–38mm, voltage: under 24V, output power: under 50W, output speed: 5rpm–2000rpm, speed ratio: 5–1500. Output torque: 1.0 gf.cm –50kgf.cm. The gearbox rotation accuracy is 1–2 arc minutes, and the gear transmission noise is below 45dB. For the detailed datasheet for small DC motors, refer to the specific motor’s product page.