It is the most fundamental, reliable, and cost-effective source of power for modern power systems, industrial production, household appliances, and transportation.

1. Naturally matched with the power grid without rectification
The modern power grid produces alternating current.
The AC motor can be directly connected to the power grid to operate
No need for rectification, inversion, or complex driving circuits
Simple structure, low cost, and extremely high reliability
This is the fundamental reason why it rules the world.

2. Simple structure, durability, and affordability
Taking the most common asynchronous motor (induction motor) as an example:
No electric brushes, no commutator
Almost maintenance free, with an extremely long lifespan
Simple manufacturing and low price
In industry, a large number of fans, water pumps, compressors, and conveyor belts are almost all AC motors.

3. The power range is extremely wide, and it can be used from small to large
From small to: fans, air conditioners, washing machines, razors
From: Machine tools, fans, water pumps, air compressors
Up to: 10000 ton giant wheels, electric locomotives, steel mills, giant water pumps
It can cover from a few milliwatts to tens of thousands of kilowatts, which no other motor can achieve.

4. Suitable for long-distance power transmission and large-scale industry
AC power can be conveniently stepped up, stepped down, and transmitted over long distances, and then directly drive AC motors.
Power plant → High voltage transmission → Transformer voltage reduction → Factory/household
The entire link is naturally compatible with AC motors
This makes large-scale industrialization possible.

5. Mature control technology and strong speed regulation performance
I used to think that AC motors were difficult to speed, but now:
Inverter+AC asynchronous/permanent magnet synchronous motor
Wide speed range, high efficiency, and fast response
Already fully used for:
High speed rail, subway, electric vehicles
Elevators, machine tools, robots
Air conditioner frequency conversion, refrigerator frequency conversion
AC motors are no longer an antique that can only maintain a constant speed.

6. High efficiency and huge potential for energy conservation
Fans, water pumps, and compressors account for nearly half of the total electricity consumption in society, with the vast majority being AC motors.
After the transformation with variable frequency speed regulation, energy saving can reach 20%~50%, which is the core equipment for national energy conservation and emission reduction.