Rockwell Automation 9VT201-007HTNNN, User Manual, Page: 95 / 224

Programming and Parameters 3-33
Publication 9VT-UM001D-EN-P
D
YNAMIC CONTR
O
L
Sto
p
/B
rake
Mo
des
161
162 [Bus Reg Mode A]
[Bus Reg Mode B]
Sets the method and sequence of the DC
bus regulator voltage. Choices are
dynamic brake, frequency adjust or both.
Sequence is determined by programming
or digital input to the terminal block.
Dynamic Brake Setup
If a dynamic brake resistor is connected to
the drive, both these parameters must be
set to either option 2, 3 or 4.
Default:
Options:
1
0
0
1
2
3
4
“Adjust Freq”
“Disabled”
“Disabled”
“Adjust Freq”
“Dynamic Brak”
“Both-DB 1st”
“Both-Frq 1st”
160
163
F
ile
Gr
oup
No
.
Parameter Name and Description
See page 3-2 for symbol descriptions
Values
Re
lated
!
ATTENTION: The drive does not offer protection for externally
mounted brake resistors. A risk of fire exists if external braking
resistors are not protected. External resistor packages must be
self-protected from over temperature or the protective circuit shown
in
Figure C.1 on page C-1 (or equivalent) must be supplied.
ATTENTION: The adjust freq portion of the bus regulator function
is extremely useful for preventing nuisance overvoltage faults
resulting from aggressive decelerations, overhauling loads, and
eccentric loads. It forces the output frequency to be greater than
commanded frequency while the drive’s bus voltage is increasing
towards levels that would otherwise cause a fault. However, it can
also cause either of the following two conditions to occur:
•
Fast positive changes in input voltage (more than a 10%
increase within 6 minutes) can cause uncommanded positive
speed changes; however, an OverSpeed Limit fault will occur if
the speed reaches Max Speed + Overspeed Limit. If this
condition is unacceptable, action should be taken to 1) limit
supply voltages within the specification of the drive, and 2) limit
fast positive input voltage changes to less than 10%. Without
taking such actions, if this operation is unacceptable, the adjust
freq portion of the bus regulator function must be disabled (see
parameters 161 and 162).
•
Actual deceleration times can be longer than commanded
deceleration times; however, a Decel Inhibit fault is generated if
the drive stops decelerating altogether. If this condition is
unacceptable, the adjust freq portion of the bus regulator must
be disabled (see parameters 161 and 162). In addition,
installing a properly sized dynamic brake resistor will provide
equal or better performance in most cases.
Note that these faults are not instantaneous and have shown test
results that take between 2 and 12 seconds to occur.