8
Chain drive
Installation and Operating instructions
ELTRAL KS30/40 RADIO CONTROL
7
Calculating the opening and closing force
NOTE
With the formulae indicated below it is possible to determine the
approximate force required to open or close a window.
The windows are assumed to be smooth-running.
Possible snow loads are also to be considered.
NOTE
The application formula can only be used for Tilt-Only windows, Top-Hung
windows, and skylights.
The permitted drive force according to the technical speci
fi
cations can be
found in chapter "5 Technical data (1 motor)" on page 5.
If the values you calculated exceed the max. allowed force, please contact
Gretsch-Unitas GmbH Baubeschläge.
F, F
g
, F
K
= opening and closing force (N)
P
= sash weight (kg)
A
= window area (m²)
H
= sash height (mm)
C
= opening width of sash (mm)
F
w
= wind load
For roo
fl
ights and small domes
Calculating the drive force depending on the sash weight
P
F
g
= 5,4 x P
For vertically installed Tilt-Only or Top-Hung windows
Calculating the drive force depending on the sash weight
P
F
K
= 5,4 x P x C / H
Calculating the drive force depending on the wind load F
W
F
K
= F
W
x A / 2
Calculating the drive force depending on sash weight and wind load
F= F
g
+ F
K
Wind loads depending on the
building height
Height
F
w
0–8 m
500 N/m²
8–20 m
800 N/m²
20–100 m
1100 N/m²
> 100 m
1300 N/m²
