Winch Line Speed Q&A with Thern Winches & Cranes

The article on Thern's blog does a great job addressing six key questions about winch line speed.

It explains that line speed is the rate at which the rope moves on the winch drum and varies with load weight and the amount of cable on the drum. The right line speed is crucial for safety and efficiency.

The article differentiates line speed from line pull, noting how gear ratio and horsepower influence performance. Practical advice on selecting the appropriate line speed ensures optimal winch operation and project success​ (Thern® Winches & Cranes)​.

Below are the questions and answers. 

Your Line Speed Questions, Answered

July 1, 2024 - By Michelle H. - thern.com/blog/line-speed-questions-answered/

Q1: What is line speed, and why is it important?

A: Line speed is simply the rate at which the rope spools onto the winch drum, measured in feet (or meters) per minute. It dictates how quickly a load moves. But it’s not just about speed; line speed impacts the winch’s lifespan, the safety of your operation, and the precision of your lifts.

Q2: What’s the difference between line speed and line pull?

A: Line speed is the rate that the winch can move a load from point A to point B. Whereas line pull is the force or tension that the winch applies to the rope that will lift or pull the load.

Q3: How does the load weight and amount of cable on the drum affect speed?

A: For electric winches, the speed at which the rope pulls in (line speed) stays the same, even if the weight of the load changes. But for air winches, the line speed slows down as the load gets heavier.

With electric winches, there’s an interesting twist: the line speed gets faster as more rope layers build up on the drum. This happens because the electric motor keeps spinning at the same speed, but the larger diameter of the rope-filled drum means more rope is pulled in with each rotation.

Q4: What are the safety implications of using the wrong speed for a particular load or application?

A: Too high a speed can cause dangerous shock loading when starting or stopping. For lifting, excessive speed can lead to uncontrolled swinging and inaccurate stop positioning.

Q5: Variable vs. Fixed Line Speed: What’s the difference?

A: Variable speed winches offer flexibility, allowing operators to adjust speed for different tasks. This reduces shock loads and helps prevent overloading the winch. Fixed-speed winches are simpler and more affordable but lack this adaptability.

Q6: How do gear ratio and horsepower affect line speed and pulling power?

A: For electric winches it means:

• • More horsepower: it can lift or pull heavier things.
  • Lower gear ratio: Less pulling/lifting power, but faster line speed.
  • Higher gear ratio: More pulling/lifting power, but slower line speed.

For more detailed information, you can read the full article from Thern here.