Salicru SLC CUBE 3+ Mode D'emploi page 100

(Q5)
(Q1a)
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Fig. 25. SLC CUBE3+ UPS single line diagram with operating
flows.
(Q5)
(Q4a)

(Q1a)

Fig. 26. SLC CUBE3+ B UPS single line diagram with oper-
ating flows.
4.3.5. Static bypass stage.
When the inverter can't keep the voltage to the critical loads due to
overloads, short-circuits, current limits or faults, the UPS from SLC
CUBE3+ series has a bypass circuit, which supplies isolation for
the inverter and supplies the critical loads directly from electrical
mains.
The UPS controls the availability inverter-bypass permanently in
order to make the shifting between them.
The bypass stage is based on six double thyristors in semipack
format, working as AC switches, three of them are for shifting the
input over the output and the other three are for shifting the inverter
over the output.
The managing system of the SCR switches is based on drivers de-
signed with a shifting system that responds to the following re-
quirements:
• Full static shifting system.
• Shifting with no high transient currents.
• Shifting with no transfer time.
100
Maintenance line (manual Bypass).
Emergency line (static Bypass).
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 
(Q3)
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 Maintenance line (manual Bypass).

Emergency line (static Bypass).
 
 
(Q3)




Normal operating.

Mains fault.

Operating with inverter non-active (EPO condition to «Off»).

Operating over manual bypass.



Normal operating.

Mains fault.

Operating with inverter active (EPO condition to «On»).

Operating over manual bypass.
The control algorithm of the triggering signals of the thyristors as-
sures a nil transfer time, and avoids short-circuits between the thy-
ristors of bypass and inverter (shifting with zero cross current).
4.3.6. Maintenance or manual Bypass.
UPSs from SLC CUBE3+ series are foreseen with an auxiliary line
protected by a circuit breaker switch, which makes an electrical
bridge between the input and output terminals.
Managing this switch,properly together with the input and output ,
allows isolating electrically all the UPS elements from the electrical
lines.
The type of manoeuvring of the maintenance bypass is "make be-
fore break", with the purpose of keeping the critical loads fed, even
during the maintenance tasks.
(Q2)
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 (Q2)
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USER MANUAL