Detailed Explanation of Elevator Electric Traction System

‌The electric traction system of an elevator refers to a system that is powered by an electric motor and controls the operation of the elevator through the joint action of components such as the power supply system and the speed feedback device. The electric traction system is the core of the electrical part of the elevator, responsible for providing the power required for the operation of the elevator and realizing speed control. ‌

The importance of the electric traction system of the elevator:

●Safety and reliability

The electric traction system of the elevator is the key to the safe operation of the elevator, and its stability and reliability are directly related to the safety and comfort of the passengers.

●Energy saving and environmental protection

The electric traction system of the elevator adopts advanced energy-saving technology and environmentally friendly materials, which can reduce energy consumption and reduce the impact on the environment.

●Improve efficiency

The electric traction system of the elevator can improve the operating efficiency and response speed of the elevator and shorten the waiting time of passengers through intelligent control and optimized design.

Classification of electric traction systems of elevators:

●AC pole-changing speed regulation system:

Using a two-speed or multi-speed motor as the power, changing the number of motor pole pairs when changing speed (similar to car gear shifting) and using a contactor to directly control the motor. When starting and braking, a resistor or reactor is connected in series in the circuit to limit the current and improve the running impact. The control system is simple, low cost, and poor comfort, suitable for low-speed elevators and freight elevators.

●Five forms of elevator electric traction

1 DC motor

2 Permanent magnet synchronous motor

3 AC pole-changing speed regulation

4 AC voltage regulation speed regulation

5 AC frequency conversion speed regulation

●AC voltage regulation speed regulation system:

Generally, a two-speed motor or an electric motor with an eddy current brake is used as the power, the high-speed winding is electrically operated, the low-speed winding or eddy current brake is DC braked, the thyristor closed loop or semi-closed loop control, has a better running comfort: the leveling accuracy ratio is high: better than the two-speed elevator, suitable for medium-speed elevators. However, the energy consumption is large and the motor heats up, so the motor is equipped with a temperature protection device. With the emergence of frequency conversion technology, it is basically an obsolete product.

●Frequency conversion speed regulation system:

Using a single-speed motor as the power source, using power semiconductor components for power supply,: adjusting the power supply voltage and frequency, changing the motor speed is a stepless speed regulation). The speed regulation performance reaches the level of a DC motor, and the running comfort is good: the leveling accuracy is high: energy feedback device can be provided: energy saving and environmental protection: is the inevitable development. With the extensive application of frequency converters, the cost is gradually reduced. Disadvantages: high cost and complex system.

●DC traction system:

AC motor is used to drive DC generator, control the excitation size of the generator. Change the generator voltage to provide power to the DC motor. Or directly control the thyristor rectifier to power the DC motor. Generally used for high-speed elevators with good running comfort and high leveling accuracy. With the development of frequency conversion technology, it will be replaced by frequency conversion control. Main disadvantages: using generator system, large size, low energy utilization rate, and high noise.