How Does Overhead Crane Work?

Overhead crane, also known as bridge crane, runs on the elevated track. The bridge of the crane runs longitudinally along the tracks laid on both sides of the runway beams, and crane trolley runs transversely along the track laid on the bridge, forming a rectangular working range, which can make full use of the space under the bridge to lift materials, without obstructed by the ground equipment. Overhead crane is widely used in indoor and outdoor warehouses, factories, docks, open storage yards, etc.

Overhead crane is generally composed of bridge running mechanism, crane trolley, and bridge metal structure. The lifting trolley is composed of lifting mechanism, trolley running mechanism and trolley frame. The lifting mechanism includes brake, motor, reducer, drum and pulley set. The motor drives the drum to rotate through the reducer, so that the wire rope is wound the drum in and out to raise and lower the load. Trolley frame is a support frame for installing components such as lifting mechanism and trolley running mechanism, and is usually a welded structure.

Overhead Cranes For Sale
Overhead Cranes For Sale

The driving modes of the crane running mechanism can be divided into two categories: one is centralized driving, that is, a motor drives a long transmission shaft to drive the driving wheels on both sides; the other is driving separately, that is, each of the driving wheels is driven by a separate motor.

Medium and small bridge cranes often use a “three-in-one” drive method in which brake, reducer and motor are combined into one. For large overhead cranes, the drive device often uses universal joint for easy installation and adjustment.

Crane Working Environment and Conditions:

  1. The power supply of the crane is three-phase AC (three-phase four-wire system), the frequency is 50Hz / 60Hz, and the voltage is ≤1000V (can also be 3kV, 6kV or 10kV according to your needs). The voltage fluctuation of the power supply system at the access point of the crane feeder should not exceed ± 10% of the rated voltage.
  2. The track installation for the crane shall meet GB / T tolerance requirements.

The grounding resistance of the crane running track should not be greater than 4Ω.

The altitude of the place where the crane is installed and used does not exceed 1000m (if it exceeds 1000m, the capacity of the motor should be checked according to the provisions of GB 755, and when it exceeds 2000m, the capacity of the electrical components should be checked.)

  1. The radiant heat temperature of the hoisted items to the hook of the crane should not exceed 300 ° C.
  2. Climatic conditions when the crane is working indoors:

The ambient temperature does not exceed + 40 ° C, and the average temperature within 24h does not exceed + 35 ° C.

Ambient temperature is not lower than -5 ° C; relative humidity does not exceed 50% at + 40 ° C.

  1. Climatic conditions when the crane is working outdoors:

The ambient temperature does not exceed + 40 ° C, and the average temperature within 24h does not exceed + 35 ° C.

The ambient temperature is not lower than -20 ° C, and the relative humidity is allowed to temporarily reach 100% when the ambient temperature does not exceed + 25 ° C.

  1. The working wind pressure should not be greater than: 150Pa inland (equivalent to class 5 wind) and 250Pa in coastal area (equivalent to class 6 wind); maximum wind pressure in non-working state: generally 800Pa (equivalent to class 10 wind).

For more information about our overhead cranes, contact us at any time.

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