# An Introduction to Small DC Motor

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A small DC motor denotes a rotating motor whose power supply is DC electric energy, also called a micro DC motor. It is the earliest invention of a device that can convert electrical energy into mechanical energy and can be traced back to the dish-type motor invented by Faraday.

### How Does A Small DC Motor Work?

A small DC motor comprises a rotor and a stator. The stator is usually placed on the outside of the motor while the rotor on the inside. DC will power the rotor with coil windings, and the stator will include a magnet source, which is either permanent magnets or electromagnetic windings. When the motor is powered by DC, a magnetic field is created within the stator, attracting and repelling the magnets on the rotor; this will drive the rotor to rotate. To keep the rotor rotating, the motor is equipped with a commutator. When the rotor is aligned with the magnetic field, it stops rotating; however, in this case, the commutator reverses the current through the stator, thereby reversing the magnetic field. This way, the rotor can keep rotating.

### The Characteristics of Small DC Motor

1. The efficiency of a small DC motor is usually higher than that of other types of motors. To attain the same output power, the volume of the DC motor is typically smaller. Small DC motors are relatively suitable for limited spaces.
2. The small DC motor has a feature that the motor can automatically decrease the speed based on the load size to achieve an excellent starting torque; AC motors are more difficult to realize this. In addition, the DC motor is easier to absorb sudden changes in the load size, and the motor speed can automatically adapt to the load size.

For a better understanding of the small DC motor, some examples will be demonstrated below.

### 1) Small 1.5 volt DC Motor

ZHAOWEI 3.4mm DC motor is a small 1.5volt DC motor, whose parameters are as follows:

1. Rated Voltage: 1.5-5V
4. Rated Load Speed: 2.4-300 rpm
5. Rated Load Current: 220 mA

### Use Case of Small 1.5volt DC Motor

ZHAOWEI gear motor for e-cigarette  adopts a small 1.5volt DC motor with a 3.4MM planetary gearbox. ZHAOWEI creatively adds the micro-lifting device to the design of the electronic cigarette. When the user uses it, he needs to press the power button. When the atomizing device base of e-cigarettes rotates out, the concealed cigarette mouthpiece is automatically raised. When the tank of the electronic cigarette rotates in the opposite direction with respect to the atomizing device base, the concealed cigarette mouthpiece automatically moves downward to be hidden in the mouthpiece cover. It realizes the lifting mechanism for electronic cigarette in a limited space.

### 2) Small 9 volt DC Motors

ZHAOWEI 12mm DC motor is one of small 9 volt DC motors, whose parameters are as follows:

1. Rated Voltage: 3-24V
4. Rated Load Speed: 5-1525 rpm
5. Rated Load Current: 255-260 mA

### Use Case of Small 9 volt DC Motor

ZHAOWEI gear motor for portable photo printer has small size and high torque, enabling the user to operate it by one hand. With the adoption of POM material and gear tooth profile optimization, the gear motor enables the portable photo printer to operate at low noise.

### 3) Small 24v DC Motor

ZHAOWEI 38mm DC motor is a small 24v DC motors, whose parameters are as follows:

1. Rated Voltage: 3-24 V
4.  Rated Load Speed: 3-1,294 rpm
5. Rated Load Current: 1,679-1,684 mA

### Use Case of Small 24v DC Motor

ZHAOWEI uses a 38-mm DC motor with a customized worm gearbox to realize the opening and closing of intelligent express cabinet and fulfill the driving demand of small volume and high torque. The unlocking and locking functions of the lock cylinder can be effectively regulated by the transmission of the gear motor; this design makes the lock cylinder controllable, highly reliable (to avoid the situation where the smart lock cannot be opened), and has a long life, realizing the safety and reliability of the smart door lock. After a detailed introduction to the small DC motor, you may have a basic understanding already. Last but not the least, you should have a glimpse of the advantages and disadvantages of the micro DC motor:

1. The electric potential waveform of the micro DC motoris better, and it is less affected by electromagnetic interference.
2. The small DC motor has a wide range of speed regulation and smooth speed regulation characteristics.
3. The DC motor has a strong overload capacity and a high starting and braking torque.
4. Due to the presence of the commutator, its manufacturing is complicated and the cost is high.