Block Protection - Siemens SINAMICS S120 Function Manual

Reducing the output frequency has the effect of significantly reducing the converter output
current which, in turn, reduces losses in the power unit.
● No reduction (p0290 = 1)
You should choose this option if it is neither possible to reduce the pulse frequency nor
reduce the output current. The converter does not change its operating point once an alarm
threshold has been overshot, which means that the drive can be operated until it reaches its
shutdown values. Once it reaches its shutdown threshold, the converter switches itself off
and the "Overtemperature, overload" fault is output. The time until shutdown, however, is not
defined and depends on the degree of overload.
To ensure that an alarm can be output earlier or that the user can intervene, if necessary, in
the drive process (e.g. reduce load/ambient temperature), only the alarm threshold can be
changed.
Function diagrams (see SINAMICS S List Manual)
● 8014 Thermal monitoring, power unit
Overview of key parameters (see SINAMICS S List Manual)
● r0036 Power unit overload
● r0037 Power unit temperatures
● p0290 Power unit overload response
● p0294 Alarm threshold I
8.3

Block protection

Description
The error message "Motor blocked" is only triggered if the speed of the drive is below the
variable speed threshold set in p2175. With vector control, it must also be ensured that the
speed controller is at the limit. With V/f control, the current limit must already have been
reached.
Once the ON delay (p2177) has elapsed, the message "Motor blocked" and fault F7900 are
generated.
Drive Functions
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4
t overload power unit
2
Monitoring and protective functions
8.3 Block protection
293