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3 Installation
Switch-on
sequence
A
Control inputs
3.2 Filtering and interference suppression
3.3 Installation site and climatic conditions
18
The supply voltages for the load and control circuitry must be switched on
at the same time.
In no circumstances should the supply voltage for the control
electronics be switched on before the voltage for the load!
This is especially important for operating transformer loads and re-
sitive loads with a large variation between hot and cold resistance!
The control connections (inputs and outputs) are designed for safety sepa-
ration from the supply line input (SELV). In order not to diminish this safety
separation, all connected circuits must also have safety separation. The
auxiliary voltages which are required must be safe extra-low voltages
(SELV).
V
Connections must only be wired up by properly qualified
personnel!
In order to prevent radio-frequency interference, such as would occur with
phase-angle control, electrical apparatus and systems must have interference
suppression implemented.
The control electronics of the thyristor power units conforms to the EMC Di-
rective EN 61 326.
However, modules such as thyristor power units have no use by themselves,
but only as a component function within a system. For this reason, the load
circuit of the power unit must have suitable interference suppression filters fit-
ted by the system provider.
Specialist companies have appropriate ranges of filters available to deal with
these problems. Such filters are normally supplied as complete modules that
are ready to be connected up.
The installation site should be, as far as possible, free from vibration. Electro-
magnetic fields, caused by equipment such as motors and transformers,
should be avoided. The ambient temperature at the installation site must be
within the range 0 to 45°C (measured about 100 mm below the unit) and the
relative humidity must be
in dry rooms. The inside of the unit must be kept free from conductive dirt and
corrosive gases.
The thyristor power unit must be mounted vertically, to ensure good convec-
tion cooling. If it is mounted in a switchgear cabinet, adequate ventilation must
be provided. There must be at least 100 mm free space below, and 150 mm
≤
75%. The thyristor power unit is intended for use
Power units 05.01
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