7applications – Lenze DSD User Manual
Page 125
Lenze · Drive Solution Designer · Manual · DMS 4.2 EN · 12/2013 · TD23
125
7
Applications
7.9
Hoist drive with counterweight
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Ascertainment of the height difference
For the stationary torque the maximum height difference Δh is required.
[7-100] Determination of Δh
Torque loss
For including the losses for the hoist the friction torque is calculated from the individual efficiencies.
When carrying out a dimensioning process with a user-definable motion profile, the efficiency for a
travel with the maximum stationary torque is assumed.
• The sign is considered with the fraction n/|n|.
• The friction of the cable rolls is considered as efficiency η
Pll
in a simplified manner. The efficien-
cy depends on the number of cable rolls, the reeving, and the efficiency of the individual rolls.
• The following equation calculates the torque loss in generator and motor mode:
[7-101] Equation 8: Torque loss
• The height Δh usually is the height differ-
ence from the cable end of the counter-
weight to the cable end of the payload at
the lowest position of the payload or the
counterweight.
• The yellow highlighted cable sections
(+) are decisive for the steady-state
torque.
• The cable sections (+, +) cancel
themselves out or are borne by the mount-
ing parts .
Δh
?
?
?
?
M
th
1
η
Gdn
η
Pll
η
Cor
⋅
⋅
-----------------------------------------
1
–
max M
sds
(
) nn------
⋅
⋅
=