7applications – Lenze DSD User Manual
Page 116
7
Applications
7.8
Hoist drive without counterweight
116
Lenze · Drive Solution Designer · Manual · DMS 4.2 EN · 12/2013 · TD23
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[7-82] Equation 6: Maximum diameter
Moment of inertia
The moment of inertia J does not change during the lifting cycle. It is, for instance, determined by
the mass of the hoisting cage (m
Cbn
) and the additional moment of inertia (J
add
).
[7-83] Equation 7: Fixed moment of inertia
In the case of applications with many cable rolls and a long cable, the cable rolls and the cable mass
substantially contribute to the peak torque value. For the determination of the cable mass the fol-
lowing equation can be used:
[7-84] Equation 8: Cable mass
For the total moment of inertia (J
sum
) of the application the mass of the payload is taken into con-
sideration. During the lifting cycle the mass of the payload can be different.
[7-85] Equation 9: Total moment of inertia
Stationary torque
The stationary torque is calculated from the masses assessed with the reeving N
L
.
[7-86] Equation 10: Stationary torque
Tip!
The cable mass usually can be disregarded, since the force due to weight of the cable can-
cels itself out in the case of a pulley block.
In few cases (e. g. in the case of long lifting paths), however, the cable force due to weight
has to be taken into consideration. Since it is not the total cable mass that acts effectively,
an active cable mass for the stationary torque (m
acv,Rop
) has to be specified.
d
max
d
Cor
d
Rop
2 N
Cor
1
–
⋅
(
)
⋅
+
=
J
J
add
d
max
2000
-------------
2
m
Cbn
N
L
2
-------------
m
Rop
+
⋅
+
=
m
Rop
ρ
Rop
l
Rop
⋅
10 π
d
Rop
2000
-------------
2
⋅ ⋅
=
=
J
sum
J
d
max
2000
-------------
2
m
L
N
L
2
---------
⋅
+
=
M
sds
g d
max
⋅
2000
--------------------
m
L
N
L
-------
m
Cbn
N
L
-------------
m
Rop,1
+
+
⋅
=