Is it better to have an induction motor or a permanent magnet synchronous motor?

I. Core differences between induction motors and permanent magnet synchronous motors

1. Working principle

Induction Machine: The rotating magnetic field is generated by electromagnetic induction. The rotating speed is slightly lower than the magnetic field speed (there is a slip).

Permanent-Magnet Synchronous Motor: The rotor is made of magnetically hard material (such as NdFeB). The speed is synchronized with the magnetic field, which is more efficient but relies on rare earth materials.

2. Efficiency comparison

- The typical efficiency of induction motors is 75% -90%, and the efficiency decreases significantly when the load changes (refer to IEC 60034-30).

- The efficiency of permanent magnet synchronous motors can reach 90% -96%, especially under partial load (e.g., the efficiency only decreases by 2% -3%).

3. Cost and Lifetime

- The unit price of the induction motor is low (about 50% - 70% of the permanent magnet motor), the maintenance cost is low, and the life is about 10-15 years.

- The initial cost of permanent magnets is high (30%-50% expensive), but long-term energy saving can offset the difference, and the life can reach 15-20 years, but high temperature demagnetization needs to be avoided.

II. Selection recommendations for cleaning machine scenarios

1. Industrial cleaning equipment

- Recommended permanent magnet synchronous motor: continuous operation of the next year to save about 20% -30% (10kW motor as an example, the annual operation of 4000 hours can save 8000 degrees, according to 0.6 yuan / degree calculation to save 4800 yuan).

- When high frequency shutdown or variable frequency requirements are required, permanent magnets respond faster (acceleration time is 30%-50% shorter than induction motors).

2. Home or light commercial cleaning machine

- Induction motors are more economical: power requirements are generally less than 1.5 kW, price sensitivity is high, and intermittent use makes the difference in energy efficiency not significant.

- If the average daily usage exceeds 4 hours, it is recommended that permanent magnets be given priority (electricity savings over 3 years can cover the difference).

III. Other influencing factors

- Environmental adaptability: the induction motor is resistant to high temperature and humidity, and is suitable for outdoor cleaning machines; Permanent magnet motor needs protection level IP54 or above.

- Noise level: permanent magnets operate more quietly (5-10 decibels lower than induction motors) and are suitable for indoor scenarios.