2
Switches
F1-F0
: Battery circuit breaker switch & fuses
F2
: ON – OFF and By Pass switch & fuse
F3-F4-F5
: Rectifier input switch – Input switch & fuse
MBS
: Maintenance By Pass switch.
F6
: Output switch & fuses
•
F1-F0 – Battery circuit breaker switch & fuse
Located at the input side of the device. It protects the other side of the system against any faults may occur
on the battery or the device.
•
F2 – ON – OFF switch & fuse
F2 is basically a fuse on the bypass input line and it has an integrated micro switch which is used for turning
ON and OFF the UPS. Therefore, F2 will be mentioned as ON – OFF switch.
•
F3-F4-F5 – Rectifier input fuse (switch)
These switches connect the line input to the input of the rectifier/charger. All power supplies in the equipment
connected to this switch.
•
MBS – Mechanical maintenance bypass switch
There is no fuse on the line of mechanical by pass.
When the UPS is faulty or during the maintenance period this switch is used to connect the load, directly to
the bypass line.
•
F6 – Output switch & fuses
This switch connects the output of the UPS to the load. This switch must be turned OFF after the
maintenance bypass switch is turned on properly according to its procedure. Maintenance bypass line is
connected to the output of this switch.
General description of UPS parts:
RECTIFIER/CHARGER: The first conversion stage (from AC to DC) uses a 3 phase, 6 pulse, fully controlled
rectifier to convert the incoming mains supply into a regulated DC BUS BAR. The DC BUS BAR produced by
the rectifier provides both battery charging power and power to the inverter section.
BATTERY GROUP: It keeps as an reserve DC power supply, for the inverter in case of mains failure.
Note : To increase the lifetime of the batteries keep them in room temperature (20
o
C-25
o
C).
INVERTER: It is made by utilizing the latest technology of power transistor (IGBT) and pulse width
modulation (PWM). Inverter converts dc bus voltage into (second conversion) an alternative voltage like line
voltage. And provides this voltage and frequency being fixed.
STATIC TRANSFER SWITCH (STATIC BY-PASS): The circuit block annotated contains an electronically
controlled switching circuit, which enables the critical load to be connected either to inverter output or to a by-
pass power source via the” static by-pass line”.
MECHANIC TRANSFER SWITCH (MAINTENANCE BY-PASS): Manually controlled, ”maintenance by-pass”
supply is also incorporated into the UPS design. Its purpose is to enable the critical load to be powered from
the mains (by-pass) supply while the UPS is shut down for maintenance or troubleshooting.
