Lenze DSD - Manual (Page 122)

7 Applications
7.9 Hoist drive with counterweight
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Lenze · Drive Solution Designer · Manual · DMS 4.2 EN · 12/2013 · TD23
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7.9 Hoist drive with counterweight
In comparison to winches, hoists with driving pulleys and counterweights have the advantage that
the cable length practically is only limited by the dead weight of the cables. Hoists with driving pul-
leys are basically equipped with counterweights that are conducted to the sides of the shaft, parallel
to the cabin.
Normally the counterweight is dimensioned for half the payload. This means that the hoist is in
equilibrium when half the payload is loaded. Apart from the two directions of rotation, according to
the payload also two torque directions (in motor mode, in generator mode) can occur.
The cables directly connect the cabin to the counterweight, or by means of mounting suspensions
and run through V-shaped grooves over the driving pulleys with a minimum angle of wrap. The driv-
ing pulleys that are wrapped by the cables transmit the drive torque to the cables, and thus to the
system consisting of the hoisting cage and the counterweight, by frictional locking.
For safety reasons always several parallel cables (6 to 8 cables) with a very high safety factor (factor
12) are used, so that the total load can actually be held by an individual cable. A redundant safety
concept provides for an extremely high degree of safety, also in the event of a power failure or con-
ductor failure.

Danger!
The DSD must not be used for designing lifts!
• The DSD can only calculate hoist drives with counterweight for freight elevators.
• The safety-relevant calculations required for lifts are not carried out by the DSD.
• Only design hoist drives for lifts in accordance with the applicable national and re-
gional regulations.