How the elevator traction machine works

The traction drive system of a traction elevator is illustrated in Figure 2-2. The motor, located in the machine room, is connected to a gear reducer and a brake to form the traction machine, which serves as the primary power source for the entire system. The traction steel rope is attached to one end of the traction sheave, while the other end connects to the counterweight. To ensure that both the car and the counterweight can move independently along the guide rails within the hoistway, a guide wheel is installed on the traction machine to separate their paths.

The weight of the car and the counterweight exerts pressure on the traction rope, causing it to grip the traction sheave through friction. As the motor rotates, it drives the traction sheave, which in turn moves the steel rope, pulling the car up or down depending on the direction of motion. When the car ascends, the counterweight descends, and vice versa. This continuous back-and-forth movement allows the elevator to perform vertical transportation efficiently.

The relative motion between the car and the counterweight is maintained by the friction between the steel rope and the traction sheave. This force is referred to as the traction or driving force. During operation, the load in the car, its position, and the direction of travel all vary. To ensure sufficient traction under different conditions, the national standard GB 7588-1995, "Safety Code for Elevator Manufacturing and Installation," specifies that the following condition must be met:

T1/T2 × C1 × C2 ≤ efα

Where:

  • T1/T2: Represents the ratio of the larger static tension to the smaller static tension on either side of the traction sheave when the car is fully loaded (125% of rated load) at the lowest floor and the empty car is at the highest floor.
  • C1: A dynamic coefficient related to acceleration, deceleration, and special installation features of the elevator.
  • C2: An influence coefficient based on the wear of the traction sheave groove. For semicircular or notched grooves, C2 = 1; for V-shaped grooves, C2 = 1.2.
  • efα: Known as the drag coefficient, where f is the equivalent friction coefficient between the steel rope and the traction groove, and α is the wrap angle of the rope around the traction sheave.

The value of efα determines the maximum allowable T1/T2 ratio. A higher efα means a greater traction capacity, allowing the elevator to handle heavier loads and operate more safely. Therefore, the traction coefficient of an elevator directly reflects its overall traction capability.

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Product Name:Galv pole top bracket

Key words:Galv top bracket,Galv pole top support,Pole top bracket for galv

Application: Used to support post insulators on the top of utlity poles.

Technical parameters

Size:450x95

Part No.: Q.Q.Q.0000112

Material elongation:Q345.Q235

Finished: Galvanized,HDG,Plain,Painting,Dacromet,Electrogalvanizing,Oiled,Phosphorization,etc

Place of origina:China

HS Code:730820

Trademark:ZBRF

Color:Customized

Part:Power,Galv

Transport Package:Plastic Bag or Gunny bag and Wooden Case

Port of shipment:Shanghai Port,Taicang Port

Certification:CE,SGS,A.S

Tensile strength ≥410Mpa

Yield strength ≥280Mpa

Elongation≥22%

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