Rockwell Automation Flex/WebPak 3000 DC Drive DB Kit, 1.5 HP-150 HP-230V, 3HP-600 HP-460V w/o NEMA1 - Manual (Page 2)

2 Dynamic Braking Kits for FlexPak 3000 and WebPak 3000 Digital DC Drives
1.5 HP to 150HP @ 230 VAC, 3 HP to 300 HP @ 460 VAC Drives
When the motor is running normally, the drive's normally-closed DB contactor is open and the dynamic braking
resistor (dynamic braking grid) is disconnected. See figure 3.
Dynamic braking slows down a rotating DC motor and its load if the motor is disconnected from the drive. It is
typically initiated with a coast/DB stop command or a drive fault. When dynamic braking is initiated, the
normally-closed DB contactor, shown in figure 3, closes. The DB resistor is then connected across the motor
armature; A1 and A2. The motor's rotating armature now acts as a generator. The resulting current causes
braking torque in the motor. While the motor is decelerating, its energy is absorbed by the DB resistor. This
causes this resistor's temperature to increase. Dynamic braking decelerates the motor even with a drive
failure, as long as motor field excitation is maintained. This process is not controlled by software. The following
table lists the contents of the 1.5 to 300 HP Dynamic Braking kits.
Description Quantity Reliance Part Number
Contactor 1
705310-1xxA
1
1. See table 4 for the specific part number for your kit model number.
Suppressor 1 600686-33A
Resistor Assembly:
1.5 HP to 150 HP @ 230 VAC and 3 HP to 200 HP @ 460 VAC
or
250 HP to 300 HP @ 460 VAC
1
1
800160-20xx
1
802272-53x 1
Enclosure:
1.5 HP to 150 HP @ 230 VAC and 3 HP to 200 HP @ 460 VAC
or
250 HP to 300 HP @ 460 VAC
1
1
800798-54R
802272-52S