MULTI SENTRY
SPTMSTD2T16EREN
13
>6.4 STATIC SWITCH (Automatic Bypass)
A static switch is an electronic device that can automatically transfer the loads connected to the UPS to the
bypass supply in an emergency for example when:
a)
Inverter overload limits are exceeded;
b)
internal over temperature limits are exceeded;
c)
the Inverter fails;
d)
DC voltage goes outside the permitted range.
If at the time of switchover, the inverter voltage is not synchronised with that of the auxiliary power supply, the
transfer will take place with a delay of around 20 ms; in consideration of the various types of loads, this delay can
be set with “UComGP” (10÷100 ms) or the switchover can be inhibited if there is no synchronism.
Emergency Supply Voltage
Transfer to the emergency supply only takes place if the voltage and the frequency are considered 'suitable' for
the load and the limits for transfer can be set on-site by the UPS user.
Voltage range: ±10% (settable from -20% to +15%);
Frequency range: ±5% (settable from ±0,25% to ±10%)
Overload
The static switch has no over current fast protection devices to guarantee maximum continuity.
Overcurrent protection shall be provided by protective devices within the overall installation to ensure UPS
compatibility.
UPS static switch is sized to support the following overload periods; above these limits UPS is automatically turned
Off:
110% permanently
125% for 60 minutes
150% for 10 minutes
Thyristors with I
2
t (Tj=25°C) = 11.250 A
2
S for 10-20 kVA three-phase and 25.000 for 10-20 kVA monophase.
Thyristors with I
2
t (Tj=25°C) = 20.000 A
2
S for 30 kVA and 25.000 for 40 kVA.
As for further overload limit details refers to technical data table.
Redundant Auxiliary Power Supply for the Automatic Bypass
The UPS is equipped with a redundant auxiliary power supply to allow the automatic bypass to function even if
the main power supply has failed.
If the UPS fails in addition to the main power supply, the load is powered through the automatic bypass.
The multi processor card and control panel are not powered, and for this reason, all LEDs and the display are off.
