Firmware Manual

Table Of Contents
78 Program features
Settings
Parameters 01.11 DC voltage (page 115), 30.30 Overvoltage control (page 254),
30.31 Undervoltage control (page 254), 95.01 Supply voltage (page 388), and 95.02
Adaptive voltage limits (page 388).
Brake chopper
A brake chopper can be used to handle the energy generated by a decelerating
motor. When the DC voltage rises high enough, the chopper connects the DC circuit
to an external brake resistor. The chopper operates on the pulse width modulation
principle.
The internal brake choppers of ACS880 drives start conducting when the DC link
voltage reaches 1.156 × U
DCmax
. 100% pulse width is reached at approximately 1.2 ×
U
DCmax
, depending on supply voltage range – see table under Voltage control and
trip limits above. (U
DCmax
is the DC voltage corresponding to the maximum of the AC
supply voltage range.) For information on external brake choppers, refer to their
documentation.
Note: For runtime braking, overvoltage control (parameter 30.30 Overvoltage control)
needs to be disabled for the chopper to operate.
Settings
Parameters 01.11 DC voltage (page 115) and 30.30 Overvoltage control (page 254);
parameter group 43 Brake chopper (page 307).
Supply voltage range [V] (see 95.01 Supply voltage)
Level 208…240 380…415 440…480 500 525…600 660…690
Overvoltage fault limit 489/440* 800 878 880 1113 1218
Overvoltage control limit 389 700 778 810 1013 1118
Internal brake chopper at 100%
pulse width
403 697 806 806 1008 1159
Internal brake chopper at 0%
pulse width
375 648 749 780 936 1077
Overvoltage warning limit 373 644 745 776 932 1071
DC voltage at upper bound of
supply voltage range (U
DCmax
)
324 560 648 675 810 932
DC voltage at lower bound of
supply voltage range
281 513 594 675 709 891
Undervoltage control and warning
limit
239 436 505 574 602 757
Charging activation/standby limit 225 410 475 540 567 713
Undervoltage fault limit 168 308 356 405 425 535
*489 V with frames R1…R3, 440 V with frames R4…R8.