Ordinary motors: Motors are devices that convert electrical energy into mechanical energy. 70%-95% of the electrical energy absorbed by the motor is converted into mechanical energy. This is the efficiency value of the motor, which is an important technical indicator of the motor. The remaining 30%-5% is consumed by the motor itself due to heat, mechanical loss, etc., so this part of the energy is wasted.
High-efficiency motors: Motors with high energy utilization are called high-efficiency motors. For ordinary motors, it is not easy to increase the efficiency by 1%, and the materials will increase a lot. When the motor efficiency reaches a certain value, no matter how much material is added, it cannot be improved. Most of the high-efficiency motors on the market now are newer generation three-phase asynchronous motors, that is, the basic working principle has not changed.
High-efficiency motors mainly improve motor efficiency through the following means
- Add materials: increase the outer diameter of the core, increase the length of the core, increase the size of the stator slot, increase the weight of the copper wire, etc., to achieve the purpose of improving efficiency. For example, the outer diameter of the Y2-8024 motor is increased from the current φ120 to φ130, and some foreign countries have increased it to φ145, and the length is increased from 70 to 90. The amount of iron used in each motor increases by 3Kg, and the copper wire increases by 0.9Kg.
- Use silicon steel sheets with good magnetic conductivity. In the past, hot-rolled sheets with large iron loss have been used. Now, high-quality cold-rolled sheets with low loss are used, such as DW470, or even lower DW270.
- Improve processing accuracy.
- Optimize the electrical performance parameters of the motor and optimize the parameters by changing the slot shape.
- Use cast copper rotors (complex process and high cost).
Therefore, to make a truly efficient motor, a lot of cost investment is made in design, raw materials, processing, etc.
Features of high-efficiency motors
1. Save energy and reduce long-term operating costs. It is very suitable for industries such as textiles, fans, pumps, compressors, etc. The electricity bill saved in one year can recover the motor purchase cost;
2. Direct start, or speed regulation with frequency converter, can completely replace asynchronous motors;
3. The motor power factor is close to 1, which improves the quality factor of the power grid and does not require a power factor compensator;
4. The motor current is small, which saves power transmission and distribution capacity and extends the overall operating life of the system;
5. Power saving budget: Taking a 55Kw motor as an example, a high-efficiency motor saves 15% more energy than a general motor, and the electricity fee is calculated at 0.5 yuan/kWh. The cost of replacing the motor can be recovered within one year by using an energy-saving motor.