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Examoogle • User • info@examoogle.com • EE-2024-8821
Chapter 1 of 12 • Page 1 of 248🔒 Protected PDF • Watermarked
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Which are the lifting devices for loading and unloading?
Rope pulley
Chain pulley
Power chain pulley
All of these
All of these
Quick Summary: Lifting devices are essential mechanical equipment used in industrial and power system installations to safely hoist, lower, and position heavy machinery or components. Rope pulleys, chain pulleys, and power chain pulleys are all standard manual or electro-mechanical tools designed to provide mechanical advantage for such operations.
Lifting devices are essential mechanical equipment used in industrial and power system installations to safely hoist, lower, and position heavy machinery or components. Rope pulleys, chain pulleys, and power chain pulleys are all standard manual or electro-mechanical tools designed to provide mechanical advantage for such operations.
M.A.=PW — Mechanical advantage where W is load and P is effort
V.R.=dlde — Velocity ratio where de is distance moved by effort and dl by load
These devices operate on the principle of mechanical advantage, where a smaller input effort is used to lift a larger load through a pulley system. A rope pulley uses friction and tension, a chain pulley utilizes geared reduction (often a worm gear or differential), and a power chain pulley uses an electric motor to actuate the gear mechanism for high-capacity lifting.
Rope pulleys are used for light loads and simple vertical movement.
Chain pulleys (manual) rely on differential gear systems for high torque.
Power chain pulleys integrate motors for automated control in substation maintenance.
Safety factors must be calculated based on the maximum safe working load (SWL).
Reduces manual physical strain on workers.
Improves precision during component installation.
Increases site safety by minimizing manual handling risks.
Requires regular lubrication and inspection to prevent mechanical failure.
Incorrect operation can lead to catastrophic dropping of loads.
Chain pulleys have relatively low lifting speeds compared to hydraulic systems.
Switchgear installation in substations.
Transformer core lifting for maintenance.
Cable pulling and cable tray installation in industrial plants.
For heavy-duty power system equipment exceeding 5 tons, motorized electric hoists (power chain pulleys) are mandatory.
Option A, B, and C describe different degrees of mechanical assistance, all categorized under lifting tackle.
D is correct — All listed devices (rope pulley, chain pulley, and power chain pulley) are standard engineering tools used for the vertical transport and positioning of heavy electrical equipment.
Always verify the Safe Working Load (SWL) rating stamped on any lifting device against the weight of the equipment before commencing maintenance; safety in power systems is non-negotiable.