What is the difference between an external rotor motor and an ordinary axial motor?

1. The external rotor motor has the characteristics of space-saving, compact design and beautiful appearance. Suitable for installation in the impeller for optimal cooling. There is no need for V-belts, additional tension belts, or other equipment.

2. Axial fan is very widely used, that is, the airflow in the same direction as the shaft of the fan blade, such as electric fan, and the fan of the air conditioner is the axial flow mode of running the fan. It is called "axial" because the gas flows parallel to the fan axis. Axial fans are typically used where the flow requirements are high and the pressure requirements are low.

Axial fans hold the position and move the air. The axial fan is mainly composed of a fan impeller and a casing, which has a simple structure but very high data requirements.

It just feels like the mechanics are different.

It seems that the direction of the axial motor is random.

"Motor" is actually a general term for electric motors and generators, both motors and generators are divided into external rotors and internal rotors, but external rotors are rarely used. I guess when you say "external rotor motor" you mean an electric motor, right?

I haven't heard of an ordinary axial flow "motor", maybe you want to ask about an ordinary axial flow "fan", right? The axial fan needs to be driven by an electric motor, and you can use an external rotor to drive the motor, just like a household ceiling fan, which is driven by the motor shell to drive the fan blades to rotate; It can also be equipped with an inner rotor, and the blades are driven to rotate by the motor shaft, but the blades cannot be directly installed on the motor shaft, therefore, the fan with the inner rotor motor must have a hub, and the fan blades are installed on the hub, and the hub is then sleeved on the shaft. Therefore, the main purpose of the external rotor motor is to compact the structure, and the fan does not need a hub, and the shell of the motor is directly used as a hub.

However, the vast majority of axial fans are equipped with internal rotor motors.

1. Internal rotor motor:

1) Advantages: The rotation mode is that the core in the middle of the motor is a rotating body, and the output torque (refers to the motor) or the income energy (refers to the generator).

2) Disadvantages: The shaft seal of the mechanical transmission pump is easy to leak and the heat dissipation effect is not good.

2. External rotor motor:

1) Advantages: When the motor drives the external rotor (i.e. external magnet) assembly to rotate, the magnetic field lines through the action of the magnetic field pass through the isolation sleeve to drive the inner rotor (i.e. internal magnet) assembly and impeller to rotate synchronously, and the medium is completely enclosed in the static isolation sleeve, so as to achieve the purpose of pumping the medium without leakage, completely solve the shaft seal leakage of the mechanical transmission pump, and is a new type of industrial pump that is fully sealed, leak-free and pollution-free.

2) Disadvantages: Difficult to repair.

The inner rotor and outer rotor of brushless motors differ in structure and function.

Structure: The inner rotor of a brushless motor is usually a rotating shaft with magnets or permanent magnets inside, while the outer rotor is a ring that rotates around the inner rotor with magnets or permanent magnets on the outside.

Mode of movement: The inner rotor is fixed, while the outer rotor rotates around the inner rotor. This mode of motion allows the inner rotor to drive the outer rotor, thus enabling the rotation of the motor.

Control mode: The control mode of the brushless motor is realized by the current control of the electronic controller. The controller controls the rotation of the motor by detecting the position of the rotor and generating the corresponding current.

For brushless motors with internal rotor, the position of the rotor is detected by detecting the position of the magnet or permanent magnet on the inner rotor, while for the brushless motor with outer rotor, it is achieved by detecting the position of the magnet or permanent magnet on the outer rotor.

Application scenario: The internal rotor brushless Xiangqi motor is suitable for occasions that require high-speed operation and low-power applications, such as DC motors, power tools, etc. The external rotor brushless motor is suitable for occasions that require high torque and low speed operation, such as electric vehicles, robots, etc.

To sum up, the difference between the inner rotor and the outer rotor of a brushless motor lies in the structure and movement mode, control mode and application scenario.

First, the reference is different.

1. Internal rotor: a rotating body supported by an internal bearing. Rigid connections or additional shafts are available.

2. Outer rotor: a rotating body supported by an external bearing. Rigid connections or additional shafts are available.

Second, the principle is different.

1. Internal rotor: The rotor in the induction motor is composed of a rotating shaft core and a closed conductor embedded in the core, which is driven by the rotating magnetic field generated by the stator winding to produce high-speed rotary motion. The two ends of the rotor are fixed in the end cover of the motor housing with rolling bearings and vertical roller mounting.

2. External rotor: In the center of the motor, a magnetic balance is maintained. However, in the case of unstable forces, any slight displacement will cause the rotor to deviate from its original position, and may even lose contact with the stator altogether.

The suspension control residual in the radial position is used to eliminate the eccentric displacement of the rotor of the motor.

Third, the use is different.

1. Internal rotor: the main component of high-speed rotation in power machinery or working machinery such as electric motors, generators, gas turbines and turbine compressors.

2. External rotor: space-saving, compact design and beautiful features. Suitable for installation in the impeller for optimal cooling. There is no need for V-belts, additional tension belts, or other equipment.

Jiaxuan shares for you to answer.

The torque of the external rotor motor is greater than that of the internal rotor when the speed is smaller, for example, the washing machine is suitable for direct drive with the external rotor. Moreover, it has high efficiency, and is more widely used in energy-saving home appliances and electric vehicles.

The outer rotor motor is the rotor that is the outer magnetic pole. The fixed part of this motor is the coil, and the rotating part is the magnetic pole.

The inner rotor motor is the rotor and the inner coil. The fixed part of the motor is the magnetic pole, and the rotating part is the rotor coil.

In general, the internal rotor is used, which is the kind of rotating coil.

The external rotor, i.e. the motor that rotates the magnetic poles, is usually of a particularly powerful type.

Internal rotor motors and external rotor motors are two different motor structures.

The rotor of the inner rotor motor, as the name suggests, rotates inside the motor, while the outside is a fixed and immovable judge. The internal rotor motor has the advantages of compact structure, high speed and high power density. Internal rotor motors are mainly used for high-speed motors, aircraft drives and other occasions that require high speed and small footprint.

In the case of an external rotor motor, the rotor rotates on the outer layer of the motor, while the stator is installed inside. The external rotor motor has the characteristics of large torque, good starting performance and stable operation. The external rotor motor is mainly used in high-power and low-speed stalling occasions such as industrial and household appliances.

In summary, the internal rotor motor is suitable for high-power and small-space occasions, and the external rotor motor is suitable for high-power and low-speed occasions.

The main reason for the high current of the external rotor motor may be two aspects; First, the main circuit of this 32t crane has a virtual connection phenomenon, and it is possible to slip the land line to be virtually connected (brush part), and the electric beam can only be poured to increase the current when it is depressed. Second, when the mechanical assembly is too tight, the rubber balance can check the bearings. This may be the main reason for the high no-load current.

1. The difference between the inner rotor and the outer rotor is that it rotates in the first place, one rotates inside and the other rotates outside.

2. The moment of inertia of the external rotor motor is larger than that of the internal rotor, and the internal rotor motor belongs to high torque and low torque, while the external rotor motor is just the opposite.

3. The external rotor motor is simple to maintain and has good heat dissipation. The maintenance of the internal rotor motor is more difficult, and the difficulty of maintenance is also relatively high, and the internal coil cannot be wound by itself.

The selection of internal rotor and external rotor motors is considered.

1. Load inertia.

The ratio of load inertia to rotor inertia is one of the key factors in selecting a suitable motor. In rigid mechanical systems using gear reducers or worm gear reducers, the maximum recommended ratio of load inertia to rotor inertia attributed to the motor shaft is 10; For systems with belt and pulley deceleration, the maximum applicable ratio is 4.

The system should not be designed in such a way as to exceed the recommended maximum ratio of load inertia to rotor inertia attributed to the motor shaft. In a system with a high attribution load inertia, the use of an external rotor motor will be beneficial to improve the stability of the system.

Since the acceleration moment is equal to the product of the moment of inertia and acceleration to be accelerated, the internal rotor motor with small inertia is adopted, and the load can obtain a high acceleration rate, high system sensitivity, fast response and frequency bandwidth.

Another advantage of the internal rotor structure is that it is relatively easy to achieve dynamic balancing. From the point of view that the rotor is dynamically balanced, the internal rotor structure is suitable for operation at high speeds close to 9000** min) to 12000** min.

When an electric motor is running, there is a mechanical limit to high speed:

1. The inner rotor structure has no special mechanical sleeve on its outer surface and the high-speed limit is about 15000** minutes); 2. The high-speed limit of the external rotor structure is about 30,000** minutes). For very high-speed operations, the external rotor structure has obvious advantages.

2. Consideration of output torque and output power.

For a given volume, an outrunner motor has a higher output torque and output power. In the case of high-speed operation, a large part of the supply voltage will be eaten up by the back EMF of the motor windings, leaving only a small part of the supply voltage to be used to draw current. In this case, this advantage of the external rotor motor is particularly important.

However, since the stator armature of the inner rotor motor is on the outside, it is able to dissipate heat directly through the outer surface of the motor, so the inner rotor motor can be cooled more efficiently than the outer rotor motor. If the outer surface of the internal rotor motor is forced to ventilate or install a heat dissipation device, the performance of the motor will be amazingly improved.

3. Consideration of the number of motor parts.

Internal rotor motors offer two advantages:

1. In the design of the internal rotor structure, a relatively small number of parts means that it has greater inherent reliability;

2. The design is simple, which reduces the manufacturing cost of the motor and saves money for users. Therefore, from the economic point of view, the internal rotor motor should be selected if the operating speed and inertia allow.

The difference between an inner rotor and an outer rotor is whether it is an inner or an outer rotor.

Generally, the rotating part is the part embedded with magnets, and the part that does not rotate is the coil part.

In the case of the same rotor weight, the moment of inertia of the internal rotation is not as large as that of the external rotation, so the high torque of the KV of the inner rotation is low, and the external rotation is just the opposite.

The torque of the inrunner motor is small and the speed is high, and it is generally used in the vehicle model (such as car, boat and ***). Whereas, the motor of the outer rotor has better heat dissipation.

If the internal rotating motor is burned out, it is difficult to maintain, because it is impossible to wind the enameled wire by itself, and the external rotating motor can be repaired by itself.

The inner rotor and the outer rotor are distinguished according to the nature of the motor.

The inner rotor is the transmission part of the motor that is internal, and the outer motor housing is static.

The outer rotor is the motor housing rotating, and the inner part is fixed and not rotating.

There are many fans with internal rotor and outer rotor, and the outer rotor motor is used in the fan with less noise and has a better life for the long-term operation of the fan.