AEC IST5 Series, Service Manual

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2.8 General Information
General operation topology of AEC IST5 Series UPS can be recognizing as follows:
The UPS is connected to the mains voltage through the CB1 breaker. As DC bus is ramped up, the
rectifier starts to operate. Rectifier converts the AC mains to DC voltage and charges the
batteries. When the mains voltage is not available, the necessary the DC bus voltage is generated
with use of the battery voltage. DC bus voltage is then converted to mains synchronized AC
voltage by the inverter. This is a high quality voltage. Generated AC power is applied to loads
through the static semi-conductor switches and output (load) breakers.
When maintenance or repair is needed, before the Input (CB1) and Output switches (CB3) are
put to the open circuit (OFF) position, the device must be switched to static bypass mode (please
see 4.1.3.2). Consequently the maintenance switch (CB2) is put to the position closed circuit
(ON). After that first Output breaker
(CB3), then Input switches (CB1) are turned OFF
respectively.
IST5 SERIES ELECTRICAL TOPOLOGY