BRAKE CHOPPER UNIT (NXB)
vacon • 135
24-hour s358 (0)40 837 1150 • Email: [email protected]
10
10.
BRAKE CHOPPER UNIT (NXB)
10.1
Introduction
The Vacon NXB (Brake chopper unit) is a unidirectional power converter for the supply of excessive energy
from a common DC bus drive line-up to resistors where the energy is dissipated as heat. External resistors
are needed. The NXB improves the DC-link voltage controllability as well as enhances the motor drives
performance in dynamic applications.
Mechanically, the NXB module is based on inverter unit construction. The dynamic DC energy brake func-
tion is achieved through a specific NXB system software. Several NXB modules can be installed parallelly
in order to increase the braking capacity, however, the modules require mutual synchronization.
10.2
Type designation code
In Vacon type designation code, the Brake Chopper Unit is characterized by number 8, for example:
NXP 0300 5
A
0
T
0
8WF
A1A2000000
10.3
Diagrams
10.3.1
NXB Brake Chopper Unit block diagram
POWER MODULE
CONTROL MODULE
nxw15.fh11
B+
B-
Power
supply
Fan
Measure-
ments
Driver
ASIC
IGBT
bridge
U
/T1
V
/T2
W
/T3
Control
I/O
slot A
I/O
slot B
I/O
slot C
I/O
slot D
I/O
slot E
RS-232
KEYPAD
Figure 10-1. BCU block diagram