The difference between inverter motor and ordinary motor – Reynolds

Inverter motor - used for special occasions with inverter, it is different from the general motor in that a strong cooling fan is added. And the power of the fan comes from the independent power supply, can not be from the main motor, the effect of the strong cooling fan is to ensure the cooling of the motor at low speed.

The difference between inverter motor and ordinary motor – Reynolds

The difference between inverter motor and ordinary motor – Reynolds

The inverter motor can adjust the speed of the motor, and then realize the intention of saving energy according to the load situation. Generally, the motor is a device with a fixed speed and cannot be adjusted.

There is no big difference, only its coil distribution capacitance is smaller, and the resistance of the silicon steel sheet is larger, so that the impact of high-frequency pulses on the motor is smaller, and the inductance filtering effect of the motor is better.

The manufacturing process of general motors and inverter motors is very different. Generally, the motor is the power frequency motor, which only needs to consider the starting process and the working condition of the power frequency at one point, and then plan the motor; The inverter motor needs to consider the starting process and the working conditions of all points in the frequency conversion range, and then plan the motor.

There are also the following:

1. From the perspective of power frequency, the variable frequency motor is a defective motor, and the general motor is a good motor

2. Because the PWM broadening wave output by the inverter imitates sinusoidal alternating current and contains a lot of harmonics, it is generally required to enter the general motor after being filtered by the reactor, otherwise the general motor will heat up;

3. In order to get used to the PWM broadening wave output by the inverter, it imitates sinusoidal alternating current, which contains a lot of harmonics. Specially made inverter motors. The effect can actually be understood as a reactor plus a general motor;

4. That is to say, the core section of the inverter motor with the same power is larger than that of the general motor. The number of coil turns should be multi-turned, and the wire diameter should be large; The insulation should be high, and the special cooling fan motor;

5. In order to get used to the needs of weak magnetic speed regulation, the bearing capacity and high-speed rotor dynamic balance are considered;

6. This kind of inverter motor does not have better torque characteristics, and only overcomes the demand that the general motor is not accustomed to PWM broad-modulated wave to imitate sinusoidal alternating current;

7. If the inverter motor does not have the above characteristics and requirements, it is a fake inverter motor inverter.

The motor is more general than the general motor,

Constant frequency and constant voltage, the difference in structure is:

1. Insulation grade: generally F grade or higher, strengthen the insulation strength of ground insulation and wire turns, especially consider the ability of insulation to withstand impulse voltage.

2. For the vibration and noise problems of the motor: it is necessary to fully consider the rigidity of the motor mechanism and the whole, and try to increase its natural frequency to avoid the resonance phenomenon with each force wave.

3. Cooling method: Forced ventilation cooling is generally used, that is, the main motor cooling fan is driven by an independent motor.

4. To prevent shaft current, the bearing insulation method should be selected for motors with a capacity exceeding 160KW. The main reason is that the magnetic circuit is asymmetrical, and the shaft current will also occur, and when the current generated by other high-frequency weights is combined with the effect, the shaft current will be greatly increased, and then the bearing will be damaged, so the insulation method should generally be adopted.

5. For constant power variable frequency motors: when the speed exceeds 3000/min, special grease with high temperature resistance should be selected to compensate for the temperature increase of the bearing.

What are the disadvantages of long-term low-frequency operation of general motors:

1. It is a resonance problem at a certain frequency;

2. It is a heat dissipation problem, when the power supply frequency is low, the loss caused by the high harmonics in the power supply is larger, and the fan that comes with it is not enough to cool itself at other low frequencies, and the life of the motor plummets.

Compensate: In addition, the motor speed regulation can also be carried out through the hydraulic coupler. Hydraulic coupling is a kind of mechanical equipment that uses liquid medium to transmit speed, and its automatic input shaft end is connected with the original conveyor, and the driven output shaft end is connected with the load shaft end, and the speed of the output shaft can be changed by adjusting the pressure of the liquid medium. Ideally, when the pressure tends to infinity, the output speed is equal to the input speed, which is equivalent to a rigid coupling. When the pressure decreases, the output speed decreases accordingly, and the medium pressure is continuously changed, and the output speed can be stepless adjusted lower than the input speed.

However, the hydraulic coupling is worse than the inverter motor in terms of speed regulation range, speed regulation accuracy, efficiency and other links, but the price is relatively cheap.

3. Generally, the motor is not allowed to work at low frequency for a long time, otherwise it may burn out if the heat is serious.

The difference between inverter motor and ordinary motor – Reynolds

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