What is the method of braking the three phase asynchronous motor

Reverse braking, energy consumption braking, power generation feedback braking.

Mechanical braking, reverse braking, regenerative braking (energy braking). For example, the motor on the windlass on the ship often uses regenerative braking, that is, the motor that was originally used as a motor is used as a generator, and the original load torque is used to generate electricity on the armature to produce a braking torque, and then the motor slowly stops! The last mechanical braking method is that it finally stops!

Reverse braking is rarely used because it produces violent mechanical vibrations that cause a lot of damage to the motor itself.

Energy consumption braking, reverse braking, regenerative braking.

Don't forget to give points.

Three-phase asynchronous motor electric braking is commonly used in reverse braking, energy consumption braking, regenerative braking, power generation braking.

Because the rotor and stator of the three-phase asynchronous motor rotate in the same direction and at different speeds, there is a slip rate, so it is called a three-phase asynchronous motor.

The rotation speed of the rotor of the three-phase asynchronous motor is lower than the rotation speed of the rotating magnetic field, and the rotor winding generates electromotive force and current due to the relative motion between it and the magnetic field, and interacts with the magnetic field to generate electromagnetic torque to achieve energy conversion.

How it works. When a symmetrical three-phase alternating current is introduced into the three-phase stator winding, a rotating magnetic field is generated that rotates clockwise along the circular space of the stator and rotor at a synchronous speed n1. Since the rotating magnetic field rotates at n1 rotational speed, the rotor conductor is stationary at the beginning, so the rotor conductor will cut the stator rotating magnetic field and generate an induced electromotive force (the direction of the induced electromotive force is determined by the right-hand rule).

Since the two ends of the rotor conductor are shorted by short-circuit rings, under the action of induced electromotive force, the induced current in the rotor conductor will be basically consistent with the direction of the induced electromotive force.

There are three electric braking methods for three-phase asynchronous motors: energy consumption braking, reverse braking and power generation feedback braking.

The three-phase electric motor electric brake has:

Reverse braking: suitable for the occasion of steady speed lowering of potential load.

Energy consumption braking: the energy consumption braking state of three-phase asynchronous motor is not only used for parking, but also widely used in places such as lowering heavy objects.

Electromagnetic braking: the impact is large when braking, the braking is reliable, and it is generally used for lifting and winch equipment.

2 kinds: after the motor disconnects the power supply, in order to make the motor stop quickly, the power supply that is inverted with the normal operation power supply is added to the power supply of the motor by using the control method, at this time, the rotation direction of the motor rotor is opposite to the rotation direction of the rotating magnetic field of the motor, and the electromagnetic torque generated by the motor is the braking torque at this moment, and the deceleration of the motor is accelerated.

The voltage at both ends of the armature is disconnected from the power grid by using the switch Q, and it is immediately connected to a braking resistor RL, at this time, the main magnetic field in the motor remains unchanged, and the armature continues to rotate by inertia at this point This moment is the braking torque, so the motor speed decreases until it stops.

1. Mechanical braking: The method of using a mechanical device to quickly stop the motor after disconnecting the power supply is called mechanical braking. The commonly used methods of mechanical braking are: electromagnetic brake and electromagnetic clutch braking;

2. Electric braking: the motor generates an electromagnetic torque that is opposite to the direction of the rotor speed, so that the speed of the motor decreases rapidly. Among them, the commonly used electrical braking methods of three-phase AC asynchronous motors include energy consumption braking, reverse braking and feedback braking.

Energy consumption braking: When the motor cuts off the AC power supply, the method of immediately passing direct current into any two phases of the stator winding to force the motor to stop quickly is called energy consumption braking;

Reverse braking: There are two kinds, one is the reverse pull reversal braking that reverses the motor under the action of load torque, and this method can not stop accurately. the other is to rely on changing the phase sequence of the three-phase power supply in the stator winding of the three-phase asynchronous motor to generate braking torque and force the motor to stop rapidly;

Regenerative braking: also known as power generation braking and regenerative braking. Under the action of the applied torque, the rotor speed exceeds the synchronous speed, and the electromagnetic torque changes direction to become the operating state of the braking torque.

Feedback braking is different from reverse braking and energy braking, and regenerative braking cannot be braked to a standstill.

What is braking, and what are the braking methods of three-phase asynchronous motors.

After the three-phase asynchronous motor cuts off the power supply, it always rotates for a period of time according to inertia before stopping. The hook of the crane or the blue of the winch in production requires accurate positioning; The spindle of the universal milling machine needs to be able to stop quickly. These require braking of the dragging motor, and there are two main types of methods:

Mechanical braking and electric braking. 1. Mechanical braking is a braking method that uses a mechanical device to quickly stop the motor after disconnecting the power supply. Such as electromagnetic brakes, electromagnetic clutches and other electromagnet brakes.

Electromagnetic brake power-off braking control circuit. Principle analysis: close the power switch QS and switch K, the motor is connected to the power supply, and at the same time, the electromagnetic brake coil YB is energized, the armature is engaged, and the brake shoe of the brake is separated from the brake wheel by overcoming the tension of the spring, and the motor is running normally.

Disconnect the switch motor loses power, at the same time the electromagnetic brake coil YB also loses power, the armature is separated from the iron core under the action of spring tension, and the brake shoe of the brake tightly hugs the brake wheel, and the motor is braked and stopped. The switch k in the figure can be used to control the forward and reverse rotation of the motor by using the reverse switch, the main controller, the AC contactor, etc., to meet the control requirements. Inverted switch wiring:

This braking method is widely used in lifting machinery, such as cranes, winches, and electric hoists (mostly braking with electromagnetic clutches).

There are three types of combustion tracking methods for three-phase asynchronous motors: reverse braking method, energy consumption braking method and capacitive braking method.

Reverse braking method: it is characterized by rapid braking after cutting off the power supply, but the braking effect is strong, and the excitation current is large, the hardness of the mechanical characteristics of the motor is strengthened, and the impact force on the mechanical part is large, which is usually used in the occasion of large motor capacity and rapid stopping.

Energy consumption leather making and dynamic method: After cutting off the power supply, a DC current is immediately passed to the stator winding, so that the motor generates a constant electromagnetic torque for braking. This method brakes accurately, controls conveniently, but needs rectifier equipment, the volume is larger, and the DC power supply is not cut off after stopping, so it consumes more energy.

Capacitive braking method: when the motor cuts off the AC power supply, immediately to its stator winding into a group of capacitors, the state family makes the motor in the power cut-off, in a short period of time into the phase of alternating current in one direction, to produce a rotating magnetic field, and applied to the rotor cage type, the use of inertia to make the rotor produce induced current, load induced current and the rotating magnetic field interact with the other torque, to achieve braking.

Three-phase asynchronous motors have two braking modes. Mechanical and electrical braking.

Mechanical braking refers to the method of using a mechanical device to make the motor stop quickly after the motor is disconnected from the power supply, so that the motor can be slowed down.

Electromagnetic braking is a commonly used mechanical braking method.

Electric braking refers to the motor generating an electromagnetic torque in the opposite direction of the rotor speed, which causes the motor speed to drop rapidly.