S3 Maintenance Bypass
Reserve | S2 | |
Supply | ||
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S1
480V
AC Supply
IN THE ABSENCE OF A SEPARATE RESERVE SUPPLY THE RESERVE IS DERIVED FROM THE AC UTILITY INPUT WITH THE JUMPER CONNECTED AS INDICATED
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1 |
Battery |
Contactor |
240 Cells |
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(External) |
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S5
5 |
S4 |
4 |
480Y/277V
208Y/120V
Figure 2 – Block diagram – 50/80kVA
The uninterruptible power system consists of the following: |
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1 | - | RECTIFIER/INVERTER | S1 | = Equipment ON/OFF switch |
2 | - | BATTERY | S2 | = Equipment Reserve switch |
3 | - | BACKFEED PROTECTION | S3 | = Equipment |
4 | - | INVERTER STATIC SWITCH | S4 | = Equipment OUTPUT switch |
5 | - | RESERVE STATIC SWITCH | (INVERTER OUTPUT switch for 50/80kVA only) | |
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| S5 | = RESERVE OUTPUT switch for 50/80kVA only |
1.4Functions
The rectifier/battery charger transforms the alternating current of the mains supply to direct voltage to maintain the battery in a fully charged state and also supply the inverter.
The battery is an energy reserve that is used by the inverter and the load whenever the mains supply fails.
The inverter changes the direct voltage from the rectifier or from the battery into a three phase sinusoidal alternating voltage for the external supply.
The function of the electronic static switch is to select one of the two sources of alternating voltage and to supply it to the external load. The two sources of voltage supplied to the static switch are the output of the inverter and the reserve supply. In normal working conditions, the static switch supplies the load from the inverter.
The switches permits maintenance and repair of the UPS, without interrupting the supply to the load.
MI00/10056 rev. 8 —
