Siemens SIMODRIVE 611A, Installation And Planning Manual

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Siemens AG 1997 All Rights reserved 6SN1197–0AA20
SIMODRIVE 611 (PJ)
Functions – options
The transistor PWM converters can no longer be electrically braked, when the
DC link voltage exceeds a specific value, or if the electronics has failed. If the
drive represents a danger when it coasts down, the motor can be braked by
short–circuiting the armature. The armature short–circuit braking should be
made within the traversing range of the feed axis. However, it should be initiated
at the latest by the emergency limit switch.
When determining the run–on travel of the feed axis, the friction of the mechani-
cal system and the switching times of the contactors should be taken into ac-
count. In order to prevent mechanical damage, mechanical endstops should be
provided at the end of the absolute traversing range.
For servomotors with integrated holding brake, the holding brake can be simul-
taneously de–energized, in order to generate an additional braking force; this
braking torque is somewhat delayed.
!
Caution
The drive converter pulses must always first be cancelled, before an armature
short–circuit contactor is closed. This prevents the contactor contacts burning
which could destroy the PWM converter.
!
Warning
The setpoint input must always be used for standard operational braking. For
EMERGENCY OFF, terminal 64 at the drive converter should be used to initiate
braking.
The servomotor braking torque can be optimized in regenerative operation, us-
ing an armature short–circuit with an adapted external resistor circuit. The resis-
tors required externally, are listed in the motor tables.
Ordering address:
Fritzlen GmbH & Co.KG
Gottlieb–Daimler–ph.. 61
71711 Murr
Tel.: +49 07144 / 2724–25
Armature
short–circuit
braking
Brake resistors
General information on AC servomotors
3 Functions – options
3