Bosch Rexroth BT356 Manual De Instrucciones página 35

3 609 929 B68/2008-11 | BT356
The required power at the tightening position
is calculated from the speed and max. torque:
× ×
P M 2π n
=
1 1 1
× ×
P M 2π n
=
2 2 2
For a two-stage tightening case, the power
supplied at the tightening position is
approximately that as shown in the following
figure:
P/W
Screwing in
P
2
P
1
t
1
Fig. 10:
Approximately the same power is calculated
for the power loss in the servo amplifier.
Example
The following figures are available:
M = 3.6 Nm; n = 240 rpm;
1 1
M = 143 Nm; n = 24 rpm.
2 2
, × ×
P = 3 6Nm 2π 240
1
× ×
P 143Nm 2π 24
=
2
Tighten Base load
t
2
T
U
= 90W
---------
min
U
360W
=
---------
min
Bosch Rexroth AG
Calculation of power loss
An approximate power loss can be
calculated using the tables overleaf and the
following formulas.
Table 8:
Abbreviations for formulas:
h Cycle time
P Total of individual losses in the installed
G
components in accordance with Table 6
P Screw-in power loss
1
P Max. power loss during end tightening
2
t Screw-in duration
1
t Tightening duration
2
n Number of channels
P Power loss
v
Calculation of total power loss
× ×
P T + n P
G 1
P
=
----------------------------------------------------------------------------------------------------
V
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× × × ×
t + n 0.5 P t
1 2 2
T