What is the difference between a motor stepper motor?

Motor refers to a machine that converts electrical energy and mechanical energy into each other, including motors, generators, etc.; Motor in the English word motor in Chinese means: motor, engine, generally people think that it is the meaning of electric motor. It is said that the principle of electric motors was invented by a man named a motor.

The motor and the motor are the same, and it is said to be a motor because the capacity is calculated by horsepower, and the motor is calculated by wattage. It seems to be 1 horsepower = 734w,

There is no difference between a motor and a motor, and a motor is a transliteration of the motor of the motor.

A motor refers to an electric motor, which in turn includes an electric motor and a generator. Motor is the transliteration of English motor, that is, electric motor, engine. The working principle is to drive the starter rotor to rotate through electromagnetic induction, and the pinion on the rotor drives the engine flywheel to rotate.

Motor refers to an electromagnetic device that converts or transmits electrical energy according to the law of electromagnetic induction, or converts one form of electrical energy into another form of electrical energy.

Precautions for motor use

Do not plug the motor wires and motor terminals directly into household outlets to avoid electric shock. Do not touch the energized part of the energized terminal during the energizing process to avoid electric shock. Do not touch the rotating part with your hands or fingers during the power supply to avoid injury.

Be careful not to hold the shaft in place (lock) while it is always energized.

Depending on the size of the motor, even a short period of fixation may lead to a risk of burning. Please be careful if the motor is burned due to the operation of the motor (installation status, load, ambient temperature) and the heat of the motor increases.

There are three main types of stepper motors in construction: variable reluctance (VR), permanent magnet (PM) and hybrid stepping (HS).

Reactive formula: There are windings on the stator and the rotor is composed of soft magnetic materials. The structure is simple, the cost is low, the step angle is small, the dynamic performance is poor, the efficiency is low, the heat generation is large, and the reliability is difficult to guarantee.

Permanent magnet type: The rotor of the permanent magnet stepper motor is made of permanent magnet material, and the number of poles of the rotor is the same as that of the stator. It is characterized by good dynamic performance and large output torque, but this kind of motor has poor accuracy and large step moment angle (generally or 15°).

Hybrid: The hybrid stepper motor combines the advantages of reactive and permanent magnet type, with multi-phase windings on the stator, permanent magnet materials on the rotor, and multiple small teeth on the rotor and stator to improve the step moment accuracy. It is characterized by large output torque, good dynamic performance, and small step angle, but the structure is complex and the cost is relatively high.

According to the winding on the stator, there are two phases, three phases and five phases and other series. The most popular is the two-phase hybrid stepper motor, which accounts for more than 97% of the market share, and the reason for this is that it is cost-effective and works well with a subdivision driver. The basic step angle of this kind of motor is step, and after the half-step driver is matched, the step angle is reduced to, and the step angle can be subdivided up to 256 times (microstep) after the subdivision driver is matched.

Due to friction and manufacturing accuracy, the actual control accuracy is slightly lower. The same stepper motor can be equipped with different subdivision drives to change the accuracy and effect.

There are many ways to classify stepper motors, and the most common way to classify them is according to the structure of the rotor and stationator.

According to the rotor structure, stepper motors are divided into: permanent magnet type, reactive type, and hybrid type. The permanent magnet rotor is a permanent magnet, the reactive rotor is a silicon steel sheet, and the hybrid type is a combination of permanent magnet and reactive, which is a silicon steel sheet sandwiched with a permanent magnet.

The cost of permanent magnet type is low, the step angle is large, the common step angle is etc., the noise is low, the shape is generally round, the outer diameter of the common shape size is 4 55mm, the output torque is relatively small, the magnet is generally ferrite, the shell is steel plate stamping and welding, and the oil-impregnated bearing. The reactive rotor is only pressed into the motor shaft on a silicon steel sheet, and the step angle is smaller than that of the permanent magnet type, but it is noisy and is rarely used now. The hybrid type combines the characteristics of permanent magnet type and reactive type, small step angle, common step angle angle, low noise, large torque, most of them are square, and the flange size is commonly 16 150mm, which is the mainstream product on the market at present.

Stepper motors are divided into single-phase, two-phase, three-phase, five-phase stepper motors according to the fixed substructure, and some stepper motors driven by two-phase unipolar drives are also called four-phase stepper motors. Single-phase stepper motors are generally only used for watch movements, two-phase stepper motors are the absolute mainstream products in the market, commonly used step angle sum, three-phase stepper motor step angle sum, five-phase stepper motor step angle sum, three-phase and five-phase stepper motor run smoother than two-phase stepper motor, high-speed torque attenuation is slower, but now the driving performance of two-phase stepper motor continues to improve, and the running smoothness and three-phase and five-phase stepper motor are getting closer and closer, but if you have to have a high-resolution stepper motor, it is better to have three-phase and five-phase stepper motors, But the cost is higher and the versatility is poor.

There are three basic stepper motor drive modes: full step, half step, and subdivision. The main difference is the accuracy of the control of the motor coil current (i.e., the excitation method).

1), whole step drive: the stepper motor driver according to the pulse direction command to the two coils of the two-phase stepper motor cycle excitation (i.e., coil charging set current), each pulse of this driving mode will make the motor move a basic step angle, that is, degree (a total of 200 step angles in a circle of the standard two-phase motor).

2) Half-step drive: when single-phase excitation, the motor shaft stops to the whole step position, after the driver receives the next pulse, if the other phase is excited and the original is in the excitation state, the motor shaft will move half a step angle and stop in the middle of the two adjacent whole step positions. In this way, the two-phase coil is single-phased, and then the biphasic excitation stepper motor rotates in half-steps per degree of pulse.

The half-step method has the advantages of double the accuracy and low vibration at low speeds.

3) Subdivision drive: The subdivision drive mode has the advantages of low speed vibration and high positioning accuracy. Segmented stepper motor drives are widely used in stepper applications where low-speed operation is sometimes required (i.e., the motor shaft sometimes operates below 60 rpm) or where positioning accuracy is required to be less than a degree.

The basic principle is to carry out precise current control of the two coils of the motor according to the sine and cosine steps respectively, so that the distance of a step angle is divided into several subdivision steps. The precision control effect produced under the subdivision needs to look at the driver's ability to control the current, which is uneven, and the accuracy of the motor cannot be determined by looking at the subdivision alone.

However, the integrated stepper motor is now in use, which is relatively simple for the application and subsequent installation.

First, the working principle is different:

1. Stepper motor: a kind of induction motor, its working principle is to use electronic circuits to turn direct current into time-sharing power supply, multi-phase timing control current, use this current to supply power to the stepper motor, the stepper motor can work normally, and the driver is to supply time-sharing power for the stepper motor, multi-phase timing controller.

2. Electric machinery (commonly known as "motor"): an electromagnetic device that realizes the conversion or transmission of electrical energy according to the law of electromagnetic induction.

Second, the scope of application is different:

1. It is not easy to use a stepper motor well, it involves many professional knowledge such as machinery, motors, electronics and computers. As an actuator, stepper motor is one of the key products of mechatronics, which is widely used in various automatic control systems. With the development of microelectronics and computer technology, the demand for stepper motors is increasing day by day, and they are used in various fields of the national economy.

3. The motor is represented by the letter M in the circuit (the old standard is D), its main role is to generate driving torque, as the power source of electrical appliances or various machinery, and the generator is represented by the letter G in the circuit, and its main role is to convert mechanical energy into electrical energy. 、

First, the number of transistors is different.

1. The unipolar drive circuit uses four transistors to drive two sets of phases of a stepper motor.

2. The bipolar stepper motor uses eight transistors to drive two sets of phases.

Bipolar stepper motor drive circuits have twice as many transistors as unipolar drive circuits, with four low-end transistors typically driven directly by the microcontroller and higher-end transistors requiring a more expensive up-end drive circuit.

Second, the connection is different.

1. The motor structure of the unipolar drive circuit contains two sets of coils with intermediate taps, and the whole motor has a total of six wires connected to the outside world.

2. The bipolar drive circuit can drive the four-wire or six-wire stepper motor at the same time, although the four-wire motor can only use the bipolar drive circuit, it can greatly reduce the cost of mass production applications.

Third, the voltage is different.

1. The transistor of the bipolar drive circuit only needs to withstand the motor voltage.

2. The unipolar drive circuit needs a clamping circuit to drive.