Higher powers are generally achieved by
connecting thyristors series divide the
voltage rather than parallel share the
current.
The standard DIN enclosure protection class
is IP30 for water-cooled converters and for
air-cooled converters.
The advantages high system voltage
are:
• reduced losses because the higher
power achieved with less current
• better cost/benefit ratio for the motor
• cheaper cables with lower cable losses
• fuses can avoided.
Special enclosures and proofing are
available comply with higher protection
classes.
For powers MW, all the modules are
mounted common base frame and fully
Water-cooled
MEGADRIVE-LCI
Rated power: MW
10
metal clad and are shipped single unit.
A high basic insulation level inside the
cubicles minimises the risk short-circuits.
Special designs are available kV.Converter design and cooling
Part water-cooled
thyristor stack
Compact and modular
The main components converter are:
• thyristor stacks with thyristor heat sinks
• snubber circuits
• gate control units with either magnetic or
optical fibre transmis
sion the control
impulses
• semiconductor
supervision devices
• reactors
• current and voltage
transformers
• fans the case of
air cooling
• cooling unit with
heat exchanger and
pumps the case
of water cooling
• control and protection
equipment
• excitation system
• local control panel
Both the power and control sections the
converter are constructed modular units. The series connection thyristors or
thyristor bridges (e. for 12-pulse operation)
has thus become standard practice for
converters with voltage ratings kV.
.
Converters for higher ratings are broken
down into suitable units for shipment.
The advantages modular construction
are:
• compactness and robustness
• fast erection site
• adaptability the customer's needs
• ease maintenance
• simple replacement components
• easy handle and ship
High voltage for high power
At the lower end the power range, single
thyristor per branch usually sufficient.g
