Short Answer:

Ropes used in power transmission are mainly of two types — fibrous ropes and wire ropes. Fibrous ropes are made from natural or synthetic fibers like cotton, hemp, or nylon, while wire ropes are made of steel or iron wires twisted together.
Fibrous ropes are used for light power transmission or when flexibility is required, while wire ropes are preferred for heavy-duty applications such as cranes, elevators, and hoists because of their higher strength, durability, and load-carrying capacity.

Detailed Explanation :

Types of Ropes Used in Power Transmission

Ropes play an important role in mechanical systems for transmitting power and motion between shafts or for lifting and pulling loads. They are flexible elements that transmit power by frictional contact between the rope and the pulley groove. The ropes used in power transmission must have high strength, durability, flexibility, and resistance to wear and environmental effects.

In mechanical systems, ropes are broadly classified into two main categories based on the material used for their construction:

1. Fibrous ropes
2. Wire ropes

Let us discuss both types in detail.

1. Fibrous Ropes

Fibrous ropes are made from natural or synthetic fibers twisted together to form strands, and several strands are further twisted to form a complete rope. These ropes are lightweight, flexible, and easy to handle. They are mainly used for light to medium power transmission where the distance between pulleys is large, and smooth, quiet operation is desired.

1. a) Materials Used in Fibrous Ropes:

• Cotton: Provides smooth operation and flexibility but has lower strength.
• Hemp: Commonly used due to its high strength and frictional grip.
• Manila: A natural fiber from the abaca plant; offers strength, durability, and resistance to moisture.
• Nylon and Polyester: Synthetic fibers with excellent strength, elasticity, and resistance to wear, oil, and water.

1. b) Characteristics of Fibrous Ropes:

• Operate quietly and smoothly.
• Suitable for long-distance power transmission.
• Can absorb shock loads due to their elasticity.
• Have less power transmission capacity compared to wire ropes.
• Require regular maintenance, including lubrication and drying to prevent rotting.

1. c) Applications of Fibrous Ropes:

• Used in light machinery and agricultural equipment.
• Common in rope drives for small workshops and mills.
• Ideal for cases where long distance and flexibility are required rather than very high power.

2. Wire Ropes

Wire ropes are made by twisting several steel or iron wires into strands, and then twisting several strands around a central core to form a complete rope. These ropes are designed for heavy-duty applications where high power and strength are essential.

1. a) Construction of Wire Ropes:
   A wire rope consists of three main components:

1. Wires: The smallest unit, made of steel, iron, or stainless steel.
2. Strands: Several wires twisted together form one strand.
3. Core: The central part that supports the strands and maintains the rope’s shape. The core can be made of fiber, steel, or synthetic material.

Common arrangements include 6×7, 6×19, or 6×37, where the first number indicates the number of strands and the second indicates the number of wires in each strand.

1. b) Advantages of Wire Ropes:

• Can transmit very high power.
• Have high tensile strength and wear resistance.
• Can withstand harsh environments, heat, and corrosion (especially stainless steel).
• Require less maintenance than fibrous ropes.
• Less slippage due to strong grip on grooved pulleys.

1. c) Applications of Wire Ropes:

• Used in cranes, elevators, and hoists for lifting heavy loads.
• Applied in mining machinery and marine operations for pulling and towing.
• Suitable for rope drives in heavy industrial systems.
• Common in aerial ropeways and construction equipment for carrying loads over distances.

1. d) Limitations of Wire Ropes:

• More expensive than fibrous ropes.
• Require proper lubrication to prevent corrosion.
• Stiffer and less flexible compared to fibrous ropes.

Comparison Between Fibrous and Wire Ropes

Property	Fibrous Rope	Wire Rope
Material	Natural or synthetic fibers	Steel or iron wires
Strength	Moderate	Very high
Flexibility	High	Moderate
Power transmission	Low to medium	High
Maintenance	Requires regular lubrication and drying	Requires occasional lubrication
Applications	Light-duty drives	Heavy-duty drives, cranes, hoists

Selection of Rope Type

The selection of rope type depends on the power to be transmitted, distance between shafts, operating environment, and load type. For example:

• If smooth operation and flexibility are required over long distances, fibrous ropes are chosen.
• For transmitting large power in industrial or construction setups, wire ropes are preferred.

Conclusion

The types of ropes used in power transmission include fibrous ropes and wire ropes. Fibrous ropes are made from materials like cotton, hemp, or nylon and are suitable for light and medium-duty applications requiring flexibility and smooth operation. On the other hand, wire ropes are made of twisted metal wires and are used for heavy-duty applications where high strength and durability are essential. Each type has its own advantages, and the selection depends on the power requirements and working conditions of the mechanical system.