MEI UPS10000, Руководство пользователя

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Front Panel – The front panel (see illustration below) provides real time information about the system
operation on the liquid crystal display (LCD) screen. The keypad enables the system operator to
command the various functions and view a number of informational screens on the 8 line by 40
character LCD display. The TRANSFER REQUEST button is used to initiate a switch between the ON
and BYPASS modes. Three lights indicate system status: the availability of AC power, if the batteries
are discharging, and an indication that the UPS needs attention. An audible alarm has also been
implemented to alert the operator to situations that need attention or the UPS batteries are discharging.
The “TRANSFER REQUEST” push-button switch is used to initiate a transfer of the load to/from the
UPS and the raw utility.
Figure 7 Front Panel Configuration
MESTA ELECTRONICS, INC.
UNINTERRUPTIBLE POWER SYSTEM
TRANSFER
REQUEST
AC LINE BATTERY
DISCHARGING
ATTENTION
0
1
2 3
4
5
6
7 8 9
HELP
SELECT
DELETE
ESCAPE
ENTER
ALARM
RESET
3.2 THEORY OF OPERATION
Mesta Electronics was the first to introduce the truly line interactive approach for UPS systems. This is
the technique whereby the UPS maintains its output continuously phase locked and voltage equalized
with the utility so that the critical load is normally supported by two sources.
The system's operation is as follows: the Mesta UPS’ inverter, when first powered on, converts battery
power to AC for the critical load. If the utility voltage is available and within usable voltage and
frequency limits, the UPS output is phase locked to the utility, and a solid state switch is activated to
connect the output to the utility. At this time, both the utility and the inverter are driving the load,
although the inverter output is reduced to slightly below the utility voltage. This enables all of the UPS
output power to be derived from the utility while also providing charge current to the batteries through
the inverter. Once the batteries are fully charged, the inverter voltage is adjusted closer to the utility
voltage to reduce the charging current.
The inverter remains "ON" all of the time that the utility power supplies the load. If the utility power
rises, dips, or totally disappears, the inverter will maintain the voltage to the critical load. The solid state
switch connecting the UPS output to the utility line is a super-fast turn-off switching device which can
be turned off within a microsecond. When the utility goes outside the acceptable voltage, frequency, or
slew rate limits (as set for any given application), the switch is opened, thus disconnecting the utility
and leaving the load to be powered by the inverter only.