It is not allowed to directly operate AC motors with DC power supply. There are essential differences in the working principle and structural design between the two. Directly connecting to DC power supply will cause the motor to malfunction and even damage the equipment.

Core reason: The essential difference between AC motors and DC motors
The operation of AC motors (such as asynchronous motors and synchronous motors) and DC motors relies on completely different principles of “magnetic field interaction”, and the nature of the power source (AC/DC) directly determines whether the magnetic field can form effective motion.

1. Fundamental conflict in working principle
The core requirement of AC motors is to rely on alternating current to generate a rotating magnetic field.
Taking the most common three-phase asynchronous motor as an example, when three-phase AC power enters the stator winding, a stable rotating magnetic field is formed inside the motor, and the rotor follows the rotation under the “traction” of this magnetic field (there is a speed difference, that is, “asynchronous”).
The problem with DC power supply: If a DC power supply is directly connected, the stator winding will generate a constant magnetic field (rather than a rotating magnetic field).

At this time, the rotor does not have the power to rotate under force and will remain stationary;
Meanwhile, a stationary rotor acts as a “short-circuit conductor” and does not generate induced currents in a constant magnetic field to balance the stator current, resulting in a sharp increase in stator winding current (similar to a “locked rotor” state).

2. Mismatch in structural design
The stator winding of AC motors (especially asynchronous motors) is designed for AC, without key components such as “commutators” for DC motors;
If direct current is applied, the winding cannot achieve alternating magnetic field changes and lacks the ability to withstand high direct current.
DC motors require components such as commutators and brushes to convert DC power into alternating current in the rotor winding to generate rotational torque, while AC motors do not have these structures and cannot adapt to DC power.

Special situation: How to “use” DC power supply for AC motors?
If a DC power supply is needed to drive an AC motor, it must be converted to AC through an intermediate device, namely a “DC-AC inverter”.
This is a common scenario in industry (such as the drive motor of new energy vehicles, which is essentially an AC motor, driven by the DC power of the power battery converted into AC power by an inverter).

Special situation: How to “use” DC power supply for AC motors?
If a DC power supply is needed to drive an AC motor, it must be converted to AC through an intermediate device, namely a “DC-AC inverter”.
This is a common scenario in industry (such as the drive motor of new energy vehicles, which is essentially an AC motor, driven by the DC power of the power battery converted into AC power by an inverter).

The specific process is as follows:
DC power supply → inverter (DC-AC conversion) → output adjustable frequency/voltage AC power → drive AC motor to operate normally
The consequences of direct access
If the DC power supply is mistakenly connected directly to the AC motor, it will result in:
The motor cannot start and the rotor is stationary;
The stator winding rapidly heats up due to overcurrent, which may burn out the insulation layer of the winding and cause damage to the motor;
If the power capacity is large, it may also cause safety issues such as power overload and tripping.

summary
Direct connection: AC motors cannot be operated directly with DC power, as it may damage the equipment.
Indirect use: DC needs to be converted to AC through an inverter to drive an AC motor.