FUNDAMENTALS
Service Manual M4 - M10
29.12.1999
Page
10
5.
FUNDAMENTALS
5.1 General description
The drive is a sophisticated example of an electrical engineering. It blends
advanced design and manufacturing to provide an outstanding combination of
reliability, performance and value of savings for the process to be controlled.
The complex design is simplified on below on block diagram to introduce
operation of the circuitry.
=
=
L1
L2
L3
PE
U
V
W
3~
3~
RS 232
P G
R
S T
M O N P A R R E F
B T N S
R U N R E
A D Y F A
U L T
K4_1
Mains
Motor
Optional
Brake
Chopper **
Power
Supply
Measure-
ments
Gate
Drivers
Motor
Control
ASIC
Motor and
Application
Control
Galvanic
Isolator
Control
Panel
Control
I/O
Option
Card
Fan
Current
Sensors
AC-choke
Rectifier
IGBT
Inverter
Brake resistor,
if optional brake
chopper is installed
Inpu
t E
M
C
-
fi
lte
r *
* CXL/CXS-model
** standard in CXS-model
Ou
tp
u
t E
M
C
-
fi
lte
r *
reactor smoothens ripple current and extends service life of DC capacitors.
The line reactor is desired component in circuitry to reduce harmonic content
produced by the rectifier.
Precharging circuitry: Precharging resistor limits surge current to the DC
capacitors, AC power is applied to the drive. One phase of the charging
contactor is by-passed by the above precharging resistor, which provides bath
for the current to charge the DC capacitors from two phases of the line.
Resistive precharging prevents high surge current from the line to cause less
stress for the power distribution system and devices on it.
The DC capacitors will be charged through the precharging resistors until
voltage in DC bus is achieved level 85% of nominal DC voltage.
