Calculation
F = m·(g+a)
When accelerating upward, acceleration adds to gravitational acceleration; when decelerating a hoisting motion, it acts in the opposite sense.
F = m·(g+a); Newtonsche Bewegungsgleichung, Dubbel Fördertechnik U 2.5 Hubwerke (Beschleunigung der Hublast)
Dynamic rope force when accelerating a hoist
When accelerating upward, acceleration adds to gravitational acceleration; when decelerating a hoisting motion, it acts in the opposite sense.
MINTSI
02
Result
Select a target and calculate.
Understand the inputs
- Rope force F — Rope tension during the acceleration phase.
- Load mass m — Mass of the lifted load including the load-handling attachment.
- Gravitational acceleration g — Local gravitational acceleration, about 9.81 m/s² near sea level.
- Acceleration a — Additional acceleration during start-up (positive) or braking (enter negative) of the hoisting motion.
Example
m=1,000 kg, g=9.81 m/s² and a=0.5 m/s² give F=1,000·10.31=10,310 N.
Assumptions and limits
Rigid, massless rope and vertical hoisting motion with no swinging; rope stretch, drum inertia and vibration effects at start-up are excluded.
Understand Dynamic rope force when accelerating a hoist
This calculator determines rope tension when starting or stopping a hoist, when an additional acceleration adds to the plain weight force.
What does this quantity describe?
When accelerating a load vertically upward, acceleration a adds to gravitational acceleration g: F=m·(g+a). When decelerating an upward motion, a acts in the negative direction and reduces rope force accordingly.
Formula and variables
F = m·(g+a)
F = m·(g+a)
| Symbol / input | Meaning |
|---|---|
| Rope force F | Rope tension during the acceleration phase. |
| Load mass m | Mass of the lifted load including the load-handling attachment. |
| Gravitational acceleration g | Local gravitational acceleration, about 9.81 m/s² near sea level. |
| Acceleration a | Additional acceleration during start-up (positive) or braking (enter negative) of the hoisting motion. |
Choose the inputs correctly
m is the lifted mass, g gravitational acceleration and a the additional acceleration during start-up (positive) or braking (negative).
How to use the calculator
Take m from the load including its handling attachment; take a from the hoist drive's acceleration or braking ramp.
Worked example
m=1,000 kg, g=9.81 m/s² and a=0.5 m/s² give F=1,000·10.31=10,310 N.
Understand the result and units
The more abrupt the start-up, the larger a and thus the dynamic additional load on the rope compared with plain weight force m·g.
m is a mass, g and a are accelerations. F is output as a force.
Typical applications
Sizing hoist ropes and chains accounting for start-up and braking shock, and a basis for choosing the safety factor.
Assumptions, limits and common mistakes
Rigid, massless rope and purely vertical motion with no swinging; rope stretch, drum inertia, vibration and jerk beyond the applied mean acceleration are excluded.
Common mistake: Do not enter a as positive when braking an upward motion by mistake; this would overestimate rope force instead of reducing it.
Frequently asked questions
What is “Dynamic rope force when accelerating a hoist” used for?
Sizing hoist ropes and chains accounting for start-up and braking shock, and a basis for choosing the safety factor.
Where do the input values come from?
m is the lifted mass, g gravitational acceleration and a the additional acceleration during start-up (positive) or braking (negative).
What does the result not cover?
Rigid, massless rope and purely vertical motion with no swinging; rope stretch, drum inertia, vibration and jerk beyond the applied mean acceleration are excluded.