Siemens SINUMERIK 840C - Manual (Page 526)

09.95 7 Drive Machine Data (SIMODRIVE Drive MD)
7.3.2 Drive MD (data description)
Generative limitation 1233
Default value Lower input limit Upper input limit Units
100.0 5.0 100.0 %
Active
at once
Input of torque limit for braking operation (generator-mode torque limit). This input value is
referred to the maximum motor-mode torque. If the 2nd torque limit is active, then the
reference value is derived from machine data MD 1230 and MD 1231. It is otherwise based on
machine data MD 1230 (1st torque limiting value).
Hysteresis P: 1232 1234
Default value Lower input limit Upper input limit Units
50.0 5.0 1 000.0 rev/min
Active
at once
Input of hysteresis for switchover speed set in machine data 1232 (Switching speed M
d1
to
M
d2
).
1st power limit value 1235
Default value Lower input limit Upper input limit Units
100.0 5.0 900.0 %
Active
at once
Input of maximum permissible output referred to normalizing motor power. In the case of feed
drives, the default values for this machine data are automatically set through a new start-up
process or by executing Calculate controller data. The default values for machine data 1235
are calculated from the following formula:
MD 1104
FDD: MD X235 = –––––––––– x 100%
MD 1118
100 % is entered as the default setting for MSD. The default settings are such that the output
is limited to the rated value at speeds above rated speed; in the case of feed drives, the
following formula is applied above rated speed:
Motor speed
–––––––––––––– x acceleration torque = constant
Rated speed
The following applies in particular to main spindle drives: If the speed at which field weakening
commences is higher than the rated value, it is possible to shorten the ramp-up times and
increase the power yield simply by raising the power limit (with unaltered current limit). Since
the current limit (MD 1238) can also limit the maximum torque which can be specified, a
further increase in the power limit may, in some cases, only result in a higher torque if the
current limit can also be raised.
Caution:
Overloading of the motor for long periods may lead to an inadmissibly high temperature rise
(shutdown on motor overtemperature) and even cause irreparable damage to the motor.
Corresponding machine data are MD 1104, MD 1145 and MD 1231 to MD 1239.
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SINUMERIK 840C (IA)