9
05.01
9.7 Circuit examples =1 to =10 with SIMODRIVE 611 analog
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Siemens AG 2001 All rights reserved
SIMODRIVE 611 Planning Guide (PJU) – 05.01 Edition
Circuit example =9 “Armature short–circuit braking”
Application
The armature short–circuit braking is only possible using permanent–magnet
motors and, for example, is only used when passing end position limit switches,
at power failure, for fault messages or EMERGENCY STOP.
Often, there is a fault/error in the NC PLC or in the drive module itself when the
software limit switch is passed. This means that electrical braking via the posi-
tion limit switches according to circuit =8 is no longer possible. For critical
drives, e.g. vertical axes, in such cases, emergency braking is still possible
using armature short–circuit braking and optionally using a holding brake (fast
stopping).
The braking torque for armature short–circuit braking is optimized using the ad-
ditional braking resistor in the motor circuit.
!
Caution
Short–circuit braking without using a brake resistor can result in partial motor
de–magnetization.
Functions
Armature short–circuit
When passing/actuating the end position limit switches or for power failure, the
pulses are inhibited via terminal 663 and, at the same time, armature short–cir-
cuit contactor –K11 is de–energized. The drive is braked after the contactor
drop–out time. The interlocking circuit, terminals 91–92 is simultaneously ope-
ned which initiates the EMERGENCY STOP function for all of the drives. The
contactor coil has a varistor in order to achieve an extremely short contactor
drop–out time. The selected auxiliary contactor of the SIRIUS series with four
pole auxiliary contact block fulfills the “protective separation” between the con-
trol voltage and 690 V AC motor circuit. The circuit must be appropriately adap-
ted for operation when the power fails, buffering the +24 V control voltage or for
other shut down functions.
Holding brake
The fast shutdown using the holding brake independent of the PLC cycle time
via the armature short–circuit contactor supports braking. The mechanical pull–
in delay of the holding brake acts somewhat delayed with respect to armature
short–circuit braking.
In the setting–up mode, the axis can be moved–away from the end position
using key–actuated switch –S13 and moved away again using pushbutton
=5–S11 enable.
9 Important Circuit Information
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