I580
GB
I
07
19
31100419
6
G
B
RECOMMENDATIONS
– Switch off power to the thyristor module every time you need to work on the electrical or mechanical equipment of the system or machine.
– A disconnecting device, such as switch disconnector, line contactor, etc. must always be included to cut off the power supply.
– Do not install the thyristor module in areas containing flammable gas or explosives.
– Do not place the thyristor module close to sources of heat.
– Do not use an insulating enclosure since they are poor heat conductors.
– You can protect the SCR's properly against short circuit only by using ultra-rapid fuses.
– Since there are ongoing conditions of DC voltage in disconnected capacitors which are equal to the peak of mains voltage, the discharging devices must be rated correctly. In practice, this means that discharging
resistors cannot be used since the constant DC voltage would destroy them. In these circumstances, it is recommended to use discharging resistors suitable for permanent connection to DC voltage to match the
voltage peak of the mains voltage at capacitor switch off. Resistors need to be dimensioned so that the capacitors are discharged in the required time after disconnecting them from the mains.
– Thyristor modules can be used to switch capacitors in 3-phase systems, in chocked and unchoked capacitor banks. It is important to keep in mind in unchoked capacitor banks that the modules can be destroyed
by current transients caused by fast voltage fluctuations. Also in chocked bank, it is imperative to control that the current values do not exceed the maximum current rating of each module.
– Thyristor modules switch without inrush current and provide smooth disconnection and high switching frequency guaranteed by the firing unit. Usage of this equipment is needed when rapid switching capacitors
at high rate.
– Thyristor modules do not electrically separate circuits. Suitable arrangements for the separation from the power system are necessary. The lines are to be protected according to electrical regulations.
– The thyristor voltage can reach a value double the mains voltage caused by the capacitor charge so especially when non-choked capacitors are used, high current can occur due to voltage transients. Furthermore
short circuits in the grid are supplied by the discharging currents of the capacitors and these current can seriously damage the thyristor modules! It is therefore recommended to protect the modules with fuses to
avoid such critical conditions. A combination of gL class fuses for the line and gR class types for the modules must be installed for protection. The use of gRL class fuses is also admissible.
CONNECTION DIAGRAMS
Induttori raccomandati
Recommended inductors
Moduli a tiristori DCTL
Tyristor module DCTL
Command with signal 8...30VDC
