Geared Variable Speed Couplings

How to operate
the coupling
The performance diagram shows
the transmittable coupling torques
M K at different scoop tube positions
as a function of the output speed.
The desired output speed becomes
a stable intersection between coupling
torque M K and load torque
(load curve).
Performance diagram
MK [%]
125
100
75
30%
50
20%
I
III
40% 50% 60% 70% 80%
1
2
II
3
4
100%
S min
25
0
10%
0%
IV
50 100
output speed [% of input speed]
Operating Ranges
I, IV Starting Range
II Control Range
III Overload Range
The shape of the coupling characteristic
curves is given for information
only, since there may be minor
deviations if coupling sizes, circulation
oil flows, oil viscosity, etc. vary.
Parameters
Scoop tube position in % of the full
scoop-tube stroke.
M K
S min
Transmitted coupling torque
Minimum slip required
for torque transmission
S = (1 - ) • 100 [%]
n 1 =
n
input 2
speed
n 1
n 2 = output speed
Typical load characteristics
1 constant torque
(e.g. positive displacement
pumps and compressors).
2 decreasing torque
(e.g. boiler feed pumps
operating at varying pressures).
3 parabolic torque
(e.g. resistance parabolae,
pumps with back pressure,
blowers).
4 decreasing torque
(e.g. boiler feed pumps
operating at fixed pressure).