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4.3 Efficiency Versus Load
Efficiency for Harmonic Drive® gears varies depending on the output torque. The efficiency curves are for gears operating at
rated output torque. Efficiency for a gear operating at a load below the rated torque may be estimated using a compensation
curve and equation as shown on the next page.
4.3.1 Efficiency Calculations
Table 24.1
Calculation Procedure
The efficiency may be determined
using the efficiency graphs.
Calculate
the torque factor V.
T
av
V =
T
N
mit:
T
= Average torque
av
T
= Rated torque at rated speed
N
K depending on gear type and V,
see illustration 24.2.
Efficiency
= η . K
η
L
Calculating Factor K
Illustration 24.4
K
24
[Equation 24.2]
[Equation 24.3]
Example
Efficiency of HFUC-20-80-2A-GR
with input speed n=1000 rpm
output torque T=19.6 Nm
at 20° C ambient temperature.
Lubrication: Grease
From matching chart
η = 78 %
T
= 19.6 Nm
av
T
= 34.0 Nm
N
19.6 Nm
= 0.57
V =
34.0 Nm
1,0
K
0,8
0,6
0,4
0,2
0
0,2 0,4
0,6 0,8
1,0
V
= 78 . 0.93 = 73 %
η
L
1019659
11/2014
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