The heat dissipation mode of hub motor can make the motor temperature reach a balance state. When the heat is increased or the heat dissipation is reduced, the balance will be broken, and the temperature will continue to rise, resulting in temperature difference between the motor and the environment, which is the phenomenon of temperature rise. In short, the temperature rise is caused by the heating of the hub motor. So what are the causes of hub motor heating? The following small series of global wind will be introduced in detail.
1. Excessive load of hub motor
Because the load power of the motor is basically constant, when the voltage is more than 10% higher than the rated value, the magnetic field strength of stator and rotor increases, and the motor runs under overload. Or the bearing of the motor is broken, so that the load of the motor is increased, resulting in the temperature rise of the motor and heating of the hub motor.
2. Motor wiring system problems
The welding of the lead wire and the wire, the connection between the lead wire and the terminal, and the diameter of the lead wire core may cause the heating of the wiring system, and directly affect the temperature of the motor winding, thus affecting the motor heating. When this kind of problem is more serious, it will lead to the local burn out of the motor in a short time, and may also spread to the stator winding directly.
3. Heating due to rotor defects
This problem mostly occurs in the hub motor with relatively large power and relatively long rotor. It is due to the casting defects of the motor rotor itself, such as the thin or broken rotor bar defect of the rotor bar, the rotor will be seriously heated during the operation of the motor, and the heat will naturally be distributed to the hub motor part, resulting in the heating of the hub motor.
4. Problems of motor bearing system
Under normal conditions, the temperature of the bearing system of the hub motor is controlled by a relatively stable limit value, which is generally controlled at 95 degrees. The actual detection process shows that when the temperature of the bearing system is high, the heat will also be transferred to the hub motor, and when the winding temperature rises, it will have adverse effects on the bearing system. The superposition of the two problems will cause the motor to have problems in a very short time Question.
5. Poor or invalid grease
Poor or failure of lubricating grease is also easy to cause hub motor heating. In addition to the motor operating in special high temperature environment, most of the motor operating temperature is below 70 degrees. If the lubricating grease is poor or fails, the wheel hub motor temperature will be too high, and the bearing will be broken and locked.
6. The problem of stator rotor bore sweeping
In normal operation of hub motor, the air gap between the stator and the rotor should be kept in a relatively uniform and stable state. However, due to some reasons (such as bearing system problems, debris problems), the virtual friction or real friction between the stator and rotor occurs, which is what we call scavenging. At this time, the friction parts will heat up, resulting in the temperature of the motor winding rising from local to overall.
7. Poor heat dissipation during motor operation
In most cases, the supporting equipment will meet the heat dissipation environment required by the operation of the hub motor. Sometimes, the motor may be in a tight air tight environment, or the environment is too narrow to exchange the heat emitted by the motor operation, which naturally increases the temperature rise of the motor. There are also cases that the heat dissipation of the hub motor is damaged, or the cooling air duct is blocked, resulting in poor heat dissipation, which makes the hub motor heat up.
8. Quality problem of motor itself
In order to save the cost, some manufacturers will reduce the number or size of the heat sink ribs, resulting in the reduction of the heat dissipation area of the motor, and produce unqualified wheel hub motor, which is also an unavoidable problem. Or the foundation of the motor is not firmly installed, resulting in vibration, causing friction and heating.
9. Fever due to other reasons
Other reasons include that the power of the hub motor does not conform to the mechanical equipment, resulting in the small horse pulling the cart; mechanical equipment failure; the tension of the belt pulley is too tight, or the rubber parts of the coupling are damaged; the voltage is low, the working current is unstable; the ambient temperature of the hub motor, etc., may cause the wheel motor heating.
The above is about the wheel motor heating reasons which answer, a total of nine aspects such as excessive load, wiring system problems. Wheel motor heating indicates that there is a fault. It is very important to solve the problem in time after determining the cause of heating. For the manufacturing of wheel hub motor, it must be produced in strict accordance with the standards and drawings to ensure the quality of the motor.
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