Advantages And Disadvantages Of IP23 Air-cooled Integrated Shaft Permanent Magnet Motor - compressor news - News

Advantages and disadvantages of IP23 air-cooled integrated shaft permanent magnet motor

Structural principle

Avantage

1. Small size, simple structure and low price.

2. Since the main rotor and the permanent magnet motor rotor adopt an integrated shaft, the transmission efficiency is 100%.

3, there is no bearing in the permanent magnet motor, saving 2 bearing costs, and completely bid farewell to bearing maintenance.

Disadvantage

1. The probability of failure of the machine is high: since the main rotor of the main rotor and the permanent magnet motor are integrated, the bearing close to the motor side (the main suction end bearing) must withstand more than 2 times the force, so the bearing and oil seal life ratio It was originally reduced by more than 2 times.

3, low-frequency heat dissipation: permanent magnet motor rotor and cooling fan blades are integrated and integrated, when the permanent magnet motor frequency control or long-term low-frequency (low speed) operation, the fan blade synchronously slows down with the motor, the cold air volume decreases, resulting in Poor heat dissipation at low frequencies can easily cause high temperatures in the motor and even high temperature demagnetization.

4, the rotor of the motor has a high congenital temperature: because the main rotor of the main rotor and the permanent magnet motor rotor adopt an integrated shaft, when the main engine is running normally, the exhaust temperature is about 80 °C, and the exhaust temperature is 100 °C or higher at high temperature, then the main engine is running. The temperature is transferred to the permanent magnet motor rotor through the direct coupling shaft, and the rotor temperature is transmitted to the motor casing.

5, low protection level: only IP23 (2 refers to the diameter of less than 12mm of solid foreign objects can easily enter the permanent magnet motor, 3 refers to the splash line with the vertical line of 60 ° or more will cause damage to the permanent magnet motor ).

6, open structure, low life: IP23 protection grade permanent magnet motor in order to ensure good heat dissipation of the motor, avoid high temperature demagnetization or even degaussing phenomenon, can only be designed as an open structure, and the air compressor is used in many environments, the air is poor Dust, environmental humidity and even corrosive gases can easily lead to reduced motor life, especially when metal-containing dust enters the motor, which will seriously affect the distribution of the magnetic wire, reduce the efficiency of the motor, and even directly scrap.

in conclusion

The above six major disadvantages make the IP23 air-cooled integrated shaft permanent magnet motor have great potential risks and should be used with caution.

Advantages and disadvantages of IP65 oil-cooled integrated shaft permanent magnet motor

Structural principle

The shaft of the male rotor of the screw head is extended from the head to form a coaxial connection with the rotor of the motor. Then, the stator and the casing of the motor are fixed on the casing of the screw head to form an integration of the motor and the nose. The lubricating oil cooled by the cooler preferentially enters the oil inlet of the oil-cooled permanent magnet motor for cooling the permanent magnet motor, and the lubricating oil after the heat exchange is discharged from the oil outlet of the permanent magnet motor through the oil filter and then enters the host. ,as shown in picture 2.

advantage

1. Since the main rotor and the permanent magnet motor rotor adopt an integrated shaft, the transmission efficiency is 100%.

2, there is no bearing in the permanent magnet motor, saving 2 bearing costs, and completely bid farewell to bearing maintenance.

3. The specific heat of oil is more than twice that of air, so the cooling effect of oil is better than that of air. In the case of ensuring the same heat dissipation of permanent magnet motor, the design of oil-cooled permanent magnet motor is much smaller than that of air-cooled permanent magnet motor. More compact and lower material costs.

4. The oil-cooled permanent magnet motor is a lubricating oil cavity between the stator and the casing. In addition to cooling the permanent magnet motor, the lubricating oil also has the effect of noise reduction and noise reduction, so the oil-cooled permanent magnet motor has low noise during operation.

5, high protection level (IP65), can better adapt to different user environments.

Disadvantage

2, maintenance trouble: Because the main rotor and permanent magnet motor rotor use an integrated shaft, in the mainframe maintenance or oil seal leakage must first remove the permanent magnet motor to remove the host, because the permanent magnet motor rotor is a permanent magnet, permanent magnet The rotor has a large magnetic force. It needs to be equipped with professional operators and tools. In addition, before the oil-cooled permanent magnet motor is disassembled, the oil in the motor should be cleaned, the inlet and outlet pipes should be removed, and new oil must be added or released before starting. The oil is re-added after filtration and is quite cumbersome.

3, the rotor of the motor has a high congenital temperature: because the main rotor and the permanent magnet motor rotor adopt an integrated shaft, when the main engine is running normally, the exhaust temperature is about 80 °C, and the exhaust temperature is 100 °C or higher at high temperature, then the main engine is running. The temperature is transferred to the permanent magnet motor rotor through the direct coupling shaft, and the rotor temperature is transmitted to the motor casing.

4, the oil affects the motor: air compressor for a variety of reasons, the temperature of the exhaust gas is high, then the temperature of the oil entering the motor is necessarily high, which will directly affect the heat dissipation of the motor, the heat dissipation of the motor will occur high temperature demagnetization or even degaussing phenomenon, If the motor is protected by high temperature, the high temperature problem of the air compressor will not be solved and the motor will not be used. In addition, the quality of lubricating oil in the air compressor market is mixed. Once carbon deposition and coking occurs, the permanent magnet motor must be high temperature, and the cleaning of the permanent magnet motor cavity is a difficult problem.

in conclusion

IP65 oil-cooled one-piece permanent magnet motor has good merits as long as it strictly controls the quality of the oil and is not too troublesome for maintenance.

IP54 air-cooled split shaft type with independent fan permanent magnet motor advantages and disadvantages

Structural principle

The main machine and the permanent magnet motor are connected through the connecting tube, and are driven by the coupling. The main machine and the permanent magnet motor are not integrated with the shaft, but are independent separate shafts, and the permanent magnet motor is equipped with an independent fan at the tail.

advantage

1. Convenient maintenance: split design - the main machine and the permanent magnet motor are connected through the connecting tube, and the drive is transmitted through the coupling. When the main engine is repaired and maintained, only the main machine is dismantled. When the motor is repaired and maintained, only the motor is dismantled, and the power frequency is not affected. The air compressor is the same.

2, independent fan design, good heat dissipation effect, wide speed range: once the air compressor starts, the independent fan runs immediately, because the rotor of the motor and the rotor of the motor cooling fan are not integrated shaft, when the motor frequency control or long-term low frequency (low When the speed is running, the independent fan is still running at the rated speed (maximum speed), the cooling air volume is constant, so that the heat dissipation of the motor is not affected by the frequency conversion speed regulation, then the speed regulation range of the permanent magnet motor is wider than that of the integrated shaft air cooling structure. .

3, high protection level (IP54), can better adapt to different user environments.

Disadvantage

1, the cost is relatively high: the air-cooled permanent magnet motor of the split shaft has one bearing before and after, a total of 2 bearings (bearings also need maintenance), no bearing of the integrated shaft; the tail of the air-cooled permanent magnet motor of the split shaft Equipped with independent fan, no integral shaft; air-cooled permanent magnet motor with split shaft has a socket, a coupling, and no integral shaft;

2. Large volume and long length: The air-cooled permanent magnet motor of the split shaft has a slender structure, and is equipped with an independent fan, which is larger in volume and longer in length than the integrated shaft.

3. One more electrical fault point: the independent fan of the air-cooled permanent magnet motor at the split shaft needs separate wiring, which will increase one electrical fault point.

in conclusion

IP54 air-cooled split shaft type with independent fan permanent magnet motor is currently the mainstream in the market (especially the power segment above 160kW), the performance is stable, the advantages and disadvantages are mixed, the overall evaluation is superior to the disadvantage.