Capstan Holding Forces
Notes & Use
Calculates the relationship between a hold-force and load-force of a flexible line wrapped around a cylinder, such as a capstan or drum.
This calculator will calculate for either the hold-force or load-force by way of a user-selected drop down menu.
Figure
Terms
$H$ = hold, pounds force (Newtons)
$w$ = number of wraps
$\Phi$ = angle of wrap, radians
$\mu$ = coeficient of friction
$L$ = Load, pounds force (Newtons)
$e$ = constant, approximately 2.71828…
Equations
Translate the number of wraps into equivalent radians:
$$ \phi = 2 \pi w $$
Calculate the load force from the holding force:
$$ L = H e ^ {\mu \phi} $$