MULTI SENTRY
SPTMSTD2T16EREN
12
Short circuit capacity
If a current surge occurs whilst the UPS is operating from the batteries (VOUT <100 Volt), the Inverter will carefully
analyse the output voltage and current in order to distinguish if the short circuit is genuine or an overload. As for
the overload limits refers to technical data table. In case UPS will detect short circuit (VOUT<100 V):
During battery operation (mains power supply failure) the Inverter can supply a current limited to 150% for 500
ms.
With mains present UPS will changeover bypass supplying limited current for 1 sec. (current >103% and output
voltage <160 Volt). Unlike, if current is greater than 150%, but voltage within the limit, UPS will not discriminate
the short circuit, continuing to feed the load for one minute; during this time upstream or downstream
protections outside UPS should be able to blow up.
The table below recommends the sizing of the various protection devices located downstream of the UPS in
order to guarantee their selectivity even in the event of a power failure:
Output protections (values recommended for selectivity)
Rapid fuses (GI)
In (Nominal current)/7
Magnetothermal switches (Curve C)
In (Nominal current)/7
Ultra-rapid fuses (GF)
In (Nominal current)/2
Output voltage symmetry
Under all conditions, output voltage symmetry is maintained within ±1%, for balanced loads and ±2% for
unbalanced loads of 100% (e.g. one phase with nominal load, the other two with no load).
Phase shift angle
The three-phase Inverter output voltages have a guaranteed phase separation angle of 120° ± 1° for balanced
loads and 100% for unbalanced loads.
Performance of a 3-phase Inverter with reactive loads
