The efficiency of a motor refers to the ratio of the shaft output power of the motor to the power drawn by the motor from the grid.
Power factor refers to the ratio of the active power of the motor to the apparent power.
Low power factor will cause large reactive current and large line resistance voltage drop, resulting in low voltage.
Why is Y2 asynchronous motor slowly replaced by high-efficiency permanent magnet motor? Please refer to the following energy-saving analysis of high-efficiency permanent magnet motors:
1. Comparison of energy saving effects
①Three-level energy-efficient YX3 motor has higher efficiency and power factor than ordinary Y2 asynchronous motor.
②The permanent magnet synchronous motor has higher efficiency and power factor than the three-level energy-efficient YX3 motor, so the energy saving effect is better.
2. Apparent power comparison
①Y2 motor P=1.732UI=29KW;
② Permanent magnet motor P=1.732UI=24.3KW;
③ The power consumption differs by 19%.
3. Part load energy analysis
①Y2 motor's efficiency declines seriously under 80% load, and the power factor declines seriously;
②The permanent magnet motor basically maintains a high efficiency and power factor between 20% and 120% of the load. The permanent magnet motor has a great energy saving advantage over the Y2 motor at part load, and even saves more than 50%.
4. Analysis of useless work consumed
① The idle current of Y2 motor is generally about 0.5 to 0.7 times of the rated current;
②The power factor of the permanent magnet motor is close to 1, no excitation current is needed, so the reactive current permanent magnet motor is about 50% different from the Y2 motor.
5. Analysis of input motor voltage
①It is often detected that if the permanent magnet motor replaces the Y2 motor, the voltage will rise generally 380V-390V. Because the power factor of Y2 motor is low, the reactive current will be large, and the voltage drop of the line resistance will be large, resulting in a low voltage.
②The total current consumed by the permanent magnet motor is high, the total current consumption is low, the line voltage drop is reduced, and the phenomenon of voltage rise occurs.
6. Motor slip analysis
① Asynchronous motors generally have a slip of 1% to 6%;
② The permanent magnet motor runs synchronously with a slip of 0, so under the same conditions, the workmanship of the permanent magnet motor is 1% to 6% more than that of the Y2 motor.
7. Motor self-loss analysis
①Take a 22-kilowatt motor as an example: Y2 motor has an efficiency of 90% and a self-loss of 10%, and the motor has a continuous self-loss of more than 20,000 kilowatts for one year;
②The efficiency of the permanent magnet motor is 95%, and the self-loss is 5%. The continuous loss of the motor for one year is about 10 thousand kilowatts. The self-loss of the Y2 motor is twice that of the permanent magnet motor.
8. Energy conservation law analysis
① The power factor is the ratio of useful work and apparent power. The Y2 motor has a low power factor, poor utilization of absorbed power, and high energy consumption;
②The permanent magnet motor has high power factor, good absorption and utilization rate, and low energy consumption.
9. Analysis of National Energy Efficiency Label
①Secondary energy efficiency of permanent magnet motor;
②Three-level energy efficiency of the most energy-saving motor YX3 motor;
③ Ordinary Y2 motors are obsolete motors and energy-consuming motors.
Power factor refers to the ratio of the active power of the motor to the apparent power.
Low power factor will cause large reactive current and large line resistance voltage drop, resulting in low voltage.
Why is Y2 asynchronous motor slowly replaced by high-efficiency permanent magnet motor? Please refer to the following energy-saving analysis of high-efficiency permanent magnet motors:
1. Comparison of energy saving effects
①Three-level energy-efficient YX3 motor has higher efficiency and power factor than ordinary Y2 asynchronous motor.
②The permanent magnet synchronous motor has higher efficiency and power factor than the three-level energy-efficient YX3 motor, so the energy saving effect is better.
2. Apparent power comparison
①Y2 motor P=1.732UI=29KW;
② Permanent magnet motor P=1.732UI=24.3KW;
③ The power consumption differs by 19%.
3. Part load energy analysis
①Y2 motor's efficiency declines seriously under 80% load, and the power factor declines seriously;
②The permanent magnet motor basically maintains a high efficiency and power factor between 20% and 120% of the load. The permanent magnet motor has a great energy saving advantage over the Y2 motor at part load, and even saves more than 50%.
4. Analysis of useless work consumed
① The idle current of Y2 motor is generally about 0.5 to 0.7 times of the rated current;
②The power factor of the permanent magnet motor is close to 1, no excitation current is needed, so the reactive current permanent magnet motor is about 50% different from the Y2 motor.
5. Analysis of input motor voltage
①It is often detected that if the permanent magnet motor replaces the Y2 motor, the voltage will rise generally 380V-390V. Because the power factor of Y2 motor is low, the reactive current will be large, and the voltage drop of the line resistance will be large, resulting in a low voltage.
②The total current consumed by the permanent magnet motor is high, the total current consumption is low, the line voltage drop is reduced, and the phenomenon of voltage rise occurs.
6. Motor slip analysis
① Asynchronous motors generally have a slip of 1% to 6%;
② The permanent magnet motor runs synchronously with a slip of 0, so under the same conditions, the workmanship of the permanent magnet motor is 1% to 6% more than that of the Y2 motor.
7. Motor self-loss analysis
①Take a 22-kilowatt motor as an example: Y2 motor has an efficiency of 90% and a self-loss of 10%, and the motor has a continuous self-loss of more than 20,000 kilowatts for one year;
②The efficiency of the permanent magnet motor is 95%, and the self-loss is 5%. The continuous loss of the motor for one year is about 10 thousand kilowatts. The self-loss of the Y2 motor is twice that of the permanent magnet motor.
8. Energy conservation law analysis
① The power factor is the ratio of useful work and apparent power. The Y2 motor has a low power factor, poor utilization of absorbed power, and high energy consumption;
②The permanent magnet motor has high power factor, good absorption and utilization rate, and low energy consumption.
9. Analysis of National Energy Efficiency Label
①Secondary energy efficiency of permanent magnet motor;
②Three-level energy efficiency of the most energy-saving motor YX3 motor;
③ Ordinary Y2 motors are obsolete motors and energy-consuming motors.
