Lenze DSD - Manual (Page 123)

Lenze · Drive Solution Designer · Manual · DMS 4.2 EN · 12/2013 · TD23
123
7 Applications
7.9 Hoist drive with counterweight
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7.9.1 Calculations
For a hoist with counterweight according to the drawing the following applies:
Effective diameter
The following equations require the effective diameter of the driving pulley which results from the
reel diameter plus the cable thickness:
[7-93] Equation 1: Effective diameter of the driving pulley
Moment of inertia
The moment of inertia J does not change during the lifting cycle. Basically it is determined by the
mass of the hoisting cage m
Cag
, the mass of the counterweight, and the additional moment of iner-
tia J
add
.
[7-94] Equation 2: Fixed moment of inertia
Typical masses of counterweight m
Ctw
can be determined from the mass of the hoisting cage m
Cbn
,
half of the payload m
L
and the reeving ratio N
Ctw
/N
L
:
[7-95] Equation 3: Mass of counterweight
In the case of applications with many guide pulleys and a long cable, the rolls and the cable mass
substantially contribute to the peak torque value. For the determination of the cable mass m
Rop
the
following equation can be used:
• If a cable pull with a shear was used, the effective cable mass would be reduced. The following
equation does not take a shear into consideration, so that in this case there is a safety reserve.
[7-96] Equation 4: Mass of the entire cable
For the total moment of inertia J
sum
of the application additionally the mass of the payload is taken
into consideration. During the lifting cycle the mass of the payload can be different.
[7-97] Equation 5: Total moment of inertia
d d
Cor
d
Rop
+ =
J J
add
d
2000
-------------
 
 
2 m
Ctw
N
Ctw
2
--------------
m
Cbn
N
L
2
------------- m
Rop
+ +
 
 
 
⋅ + =
m
Ctw
N
Ctw
N
L
------------ m
Cbn
m
L
2
------- +
 
 
⋅ =
m
Rop
ρ
Rop
l
Rop
10 π
d
Rop
200
-----------
 
 
2
⋅ ⋅ ⋅ ⋅ =
J
sum
J
d
2000
-------------
 
 
2 m
L
N
L
2
--------- ⋅ + =