5 thermal utilisation, 11 drive dimensioning – Lenze DSD User Manual
Page 339
Lenze · Drive Solution Designer · Manual · DMS 4.2 EN · 12/2013 · TD23
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11
Drive Dimensioning
11.4
Lenze gearbox selection
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11.4.5
Thermal utilisation
The heating of the gearbox depends on speed, torque, site altitude, ambient temperature and
mounting position.
• The thermal utilisation of the gearbox via a cycle results from the ratio of the instantaneous
speed value n(t) and the corresponding value n(M
S1
(t)) from the M-n characteristic.
• A PT1 element (thermal time constant τ = 15 min) determines the max. value of utilisation.
[11-14] Calculation of the thermal gearbox utilisation via a cycle
Gearbox oil
The thermal gearbox utilisation depends on the gearbox oil used. In contrast to mineral oils, syn-
thetic oils are more temperature-stable, more powerful and have a higher viscosity range.
DSD detects the thermal gearbox utilisation in two steps:
1. Utilisation when mineral oil is used.
• If the limit values are exceeded, DSD reports that the gearbox can continued to be operated
using synthetic oil.
2. Utilisation when synthetic oil is used.
• If the limit values are exceeded, DSD reports that the gearbox is overloaded.
Shaft sealing ring
Speed, oil temperature and duration of stress considerably determine the wear of the shaft sealing
ring.
Select a suitable shaft sealing ring:
• Standard shaft sealing ring when mineral gearbox oil is used.
• Viton shaft sealing ring when synthetic gearbox oil with high oil temperatures is used.
A
th
t
( )
n M t
( )
(
)
n M
S1
t
( )
(
)
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=