Operating a crane requires extensive experience to prevent unnecessary accidents. Therefore, practical insights based on experience are invaluable. Below is a summary of essential crane-related information compiled by experts, which we hope you find useful:
1 What are the primary safety protection devices for cranes?
Hoisting limit switches, travel limit switches, emergency switches and interlock switches, buffers and end stops, rail sweeps and conductor bar guards, audible and visual signals, guardrails, grounding and neutral bonding, protective covers, and other safety guards.
2 Definition of lifting machinery
Lifting machinery refers to electromechanical equipment used for the vertical lifting—or vertical lifting combined with horizontal movement—of heavy loads. Its scope is defined to include: lifts with a rated lifting capacity of 0.5 tonnes or greater; cranes with a rated lifting capacity of 1 tonne or greater and a lifting height of 2 meters or greater; and electric hoists with fixed load-bearing structures, among others. 3 Camber value formula: Camber = Span / 1000. The resulting value is the camber.
4 Causes of wheel rail-gnawing and troubleshooting methods
(1) Rail-gnawing caused by track defects
(2) Rail-gnawing caused by wheel defects
(3) Bridge structure deformation
(4) Bridge skewing during startup or braking
Methods
(1) For bridge deformation, adjust wheel positions to minimize errors in wheel span and diagonal measurements.
(2) If the issue lies with the track, correct or replace the track promptly.
(3) Eliminate electrical faults and adjust the brakes on both sides to ensure consistent braking torque and brake release timing.
5 Explain the crane's zero-position protection using the control circuit's operating principle
Zero-position protection is designed to prevent accidents where the crane starts up automatically upon the restoration of power. Such accidents could occur if a sudden power outage happens while the master controller handle is in a non-zero position (i.e., an operating position) and the operator leaves the console without returning the handle to zero. With zero-position protection in place, the crane will not start automatically when power is restored if the control handle is not in the zero position.
6 Content of safety inspections in electrical safety work
Ensure an easily accessible main disconnect switch is installed at the crane's power input and an emergency power-off switch is installed on the crane; verify that these can cut off the main power supply. Check for the presence and functionality of short-circuit, undervoltage, zero-position, and overcurrent protection for the crane's power supply and various mechanisms, as well as overspeed and loss-of-field protection for specialized cranes. Verify the completeness and effectiveness of electrical protection devices such as interlocks, interlocking circuits, and self-locking mechanisms. Check the insulation resistance of electrical circuits and ensure that the grounding resistance for electrical equipment and metal structures meets requirements. On the crane, all metal enclosures of electrical equipment that are normally de-energized, transformer cores and metal shielding layers, metal conduits and trunking, metal cable sheaths, and similar components must be reliably connected to the metal structure for protective grounding (or connection to the neutral).
