Lenze DDS Target 9300 Servo PLC V8.x - Manual (Page 87)

9300 Servo PLC
System blocks
2.12 MCTRL_MotorControl (node number 131)
2−81
L
9300 Servo PLC EN 5.1
Braking torque derating
Without a braking system being connected (934X power supply module or 935X braking unit), the
braking torque is automatically derated when the DC−bus voltage reaches the following value:
Threshold for braking torque derating + Switch−off threshold * OV reduce
·
The "OV reduce" value is set under C0172:
Code LCD Possible settings IMPORTANT
Lenze Selection
[C0172] 0V reduce 10 Threshold for activating the braking
torque derating before OU trip
0 {10 V} 100
Example:
·
C0173 = 3
ð
Switch−off threshold = 770 V
·
C0172 = 10
ð
"OV reduce" = 10 V
Threshold for braking torque derating
+ 770 V * 10 V + 760 V
ð
The braking torque is derated as soon as the DC−bus voltage reaches or exceeds 760 V.
·
Braking with active braking torque derating generates clearly audible motor noise.
Tip!
If the monitoring system responds frequently, the drive dimensioning may be inappropriate (too
much braking energy being generated).
·
Remedy: Use 934X power supply module or (additional) 935X braking units.
·
When several controllers are operated simultaneously, a DC−bus connection may be useful. In
this way the braking energy generated by one drive can be used to drive another drive. Only
the energy difference is taken from the mains.