Rockwell Automation 21G PowerFlex 750-Series AC Drives Programming Manual User Manual
Page 95
Rockwell Automation Publication 750-PM001J-EN-P - October 2014
95
Drive Port 0 Parameters
Chapter 3
DR
IV
E C
FG
Braking F
ea
tures
381
Bus Reg Kp
Bus Regulator Proportional Gain
Proportional gain for the bus voltage regulator. Sets the responsiveness of the bus
voltage regulator.
Default:
Min/Max:
10.000
0.000 / 65535.000
RW Real
382
DB Resistor Type
Dynamic Brake Resistor Type
Selects whether the internal or external DB protection will be used.
Important: Only one DB resistor can be connected to Frame 2 drives. If an external
dynamic brake is used with a Frame 2 drive, the internal dynamic brake resistor must be
disconnected. Connecting both an internal and external resistor is likely to cause drive
damage. If a dynamic brake resistor is connected to the drive, P372 [Bus Reg Mode A]
and P373 [Bus Reg Mode B] must be set to either option 2, 3, or 4; otherwise the
dynamic brake will not turn on.
Default:
Options:
0 = “Internal”
0 = “Internal”
1 = “External”
RW 32-bit
Integer
383
DB Ext Ohms
Dynamic Brake External Ohms
Used to calculate the maximum negative torque available from the dynamic brake and is
used for the external resistor dynamic brake protection.
Units:
Default:
Min/Max:
Ohms
Based on Drive Rating
Internal / 10000.00
RW Real
384
DB Ext Watts
Dynamic Brake External Watts
Sets the continuous rated power reference for the external dynamic brake resistor. Only
valid when an external dynamic brake resistor is selected (P382 [DB Resistor Type] = 1
“External”). The DB continuous watts are used in the dynamic brake thermal protection
algorithm.
Important: If customer-supplied protection is to be used in place of the drive’s
calculated resistor thermal protection, set the [DB Ext Watts] to its maximum value.
Units:
Default:
Min/Max:
Watt
100.00
1.00 / 500000.00
RW Real
385
DB ExtPulseWatts
Dynamic Brake External Pulse Watts
Sets the thermal transient response of the external dynamic brake resistor defined by
the maximum allowable power to the dynamic brake resistor for 1 second without
exceeding the resistor’s element temperature. This parameter is only valid when an
external dynamic brake resistor is selected (P382 [DB Resistor Type] = 1 “External”). If
this value is not available from the resistor vendor it can be approximated by 1 or 2
below:
1. [DB ExtPulseWatts] = 75,000 x weight (lb), where weight is the weight of the
resistor wire in pounds (not the weight of the entire resistor).
2. [DB ExtPulseWatts] = Time Constant x Brake Watts, where the Time Constant equals
the amount of time to reach 63% of its rated temperature while the maximum power
is applied to the resistor and Brake Watts is the maximum continuous power rating of
the resistor.
Many external resistor pulse watts settings are provided in the PowerFlex Dynamic
Braking Resistor Calculator, publication
onsult the resistor
manufacturer for this specification.
Important: If customer supplied protection is to be used in place of the drive’s
calculated resistor thermal protection, set the [DB ExtPulse Watts] to its maximum
value.
This information may show up on your resistor in Joules or Watt-seconds. Use that value
in this parameter. Contact the resistor manufacturer if that information is not provided.
Units:
Default:
Min/Max:
Watt
2000.00
1.00 / 100000000.00
RW Real
Fi
le
Grou
p
No.
Display Name
Full Name
Description
Values
Re
ad
-W
ri
te
Da
ta
T
ype
ATTENTION: Equipment damage may result if a drive mounted (internal) resistor is installed and this parameter is set to
“External.” Thermal protection for the internal resistor will be disabled, resulting in possible device damage.
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
(or equivalent) must be supplied.