Protective motor air duct system
The most prominent feature of the protective motor ventilation and cooling system is that the cooling medium - the air directly blows the surface of the heat-generating component, and exchanges heat directly with the environment around the motor except for the special circumstances such as the ventilation system of the pipeline. Compared with fully enclosed motor with independent circulation of internal air, heat exchange is more efficient and the choice of air duct system is more flexible and diversified. According to the main wind pressure components in the wind system where the position, the protective motor air duct system is divided into exhaust-style self-ventilation and wind-type self-ventilated two categories.
Ventilation from the ventilation
Vented self-ventilating systems are commonly used in small and medium-sized motors, with a large-diameter centrifugal fan installed at one end of the motor. The simplest axial fan Small DC motor, generally do not set the axial ventilation groove, the armature cooling only rely on its outer surface of the blowing.
In larger capacity DC motors, there is an airflow in the armature passing through the axial grooves of the commutator and the armature, in addition to a stream of air flowing over the surface of the armature and the pole coils, for parallel axial ventilation. Squirrel cage induction motor, the above similar ventilation is also more common in the cage short circuit ring with small blades, a slight increase on the short circuit of the stator windings blowing role.
In order to improve the performance of centrifugal fan, to avoid excessive noise, the distance between the fan and the cover should not be too close, should be designed as a ring-shaped collecting ditch. In addition, the inlet side of the wind shield installed in the end cap, most of the air is directed to the armature internal airflow.
Medium-sized motors, the air flow within the motor regulation problem is even more important. In this kind of motor, a wind deflector is installed at each end of the motor, and sometimes the air-side end cap increases the airflow supplement window to strengthen the cooling of the end winding part of the end winding.
Style wind self-ventilation
Noise-free motor electromagnetic load is low, each unit cooling surface loss is small, you can use the smaller diameter fan. Therefore, this type of small motor allows the use of wind-style ventilation, and install the fan in the drive.
In the open-type slip ring asynchronous motor, the application of fan-driven wind-driven self-ventilating structure at the driving end not only effectively solves the noise problem, but also realizes the task of blowing the brush-worn powder out of the machine.
Large-scale production of squirrel-cage induction motor wind fighting ventilation system is the most simple design, our country Y (IP23) series motor belongs to the structure. In this type of motor, the ventilation structure is symmetrical and the various parts of the motor are blown using the principle of radial ventilation.
Here the fan is cast aluminum rotor (squirrel cage) integrated in the short circuit ring (end ring) around the aluminum blades evenly distributed from the two sides into the air symmetrical motor, followed by blowing the stator on both sides of the termination part, Both ends of the stator core and the outer surface of the stator lamination.
Due to the small pressure that can be generated by the small diameter fan, special attention must be paid to the window designed for the air with such a ventilated motor, which must have the largest possible cross-sectional area and a smooth streamlined inlet. Small S familiar with this reason, but why the manufacturing sector operators can not profoundly understand, deviate from the design expectations are inevitable.
In all the stator and rotor core radial radial grooves on the motor, are used to fight the wind-style ventilation. The fans at both ends of the rotor strengthen the blowout of the stator termination part, sometimes the fan is made into the outer centrifugal, the inner screw double structure.