GE Industrial Solutions On-line VH Series UPS - Manual (Page 18)

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GE_UPS_OPM_VHU_0K7_2K0_XUL_V040.docx Operating Manual VH Series 700 - 1000 -1500 – 2000 VA UL
4.4.1 Standby
The UPS output is off, but the batteries are charging, see 3.5.2 step 5
4.4.2 Normal operation
See 4.3.1.
4.4.3 On bypass
The UPS is equipped with an automatic bypass switch. This switch automatically transfers the load to the mains if the UPS is
unable to deliver the demanded output power due to overload or overtemperature.
If all 4 load LEDs illuminate, bypass operation is caused by an overload. If only green load LEDs illuminate (the red load LED is
off), bypass operation is caused by overtemperature. Take appropriate measures: reduce load and/or temperature.
The UPS will switch back to normal operation when the overload has been removed or the temperature has dropped below
alarm level.
If a power failure occurs during bypass operation, the UPS will switch to battery operation and eventually, when the
batteries are depleted, output power is lost.
The bypass function can be disabled - see 4.4.6 and 4.5 for further details.
Fail safe bypass operation: if the UPS becomes defective, the load may be switched to bypass (provided that the bypass
function was not disabled). As the status of the UPS is unknown in this situation the indications on the operating panel may
differ.
4.4.4 On battery
The UPS uses the energy stored in the batteries: see section 8 ‘Batteries - runtime’.
The runtime capacity LED bar will show the remaining runtime. The UPS will shutdown:
 after the batteries have been discharged (automatic restart), or
 if keypad 'O' is pressed (restart via front panel required) or
 if a 'UPS shutdown' command is given by the computer (automatic restart)
Automatic restart depends on the setting of the ‘auto restart’ function:
- if set ‘on’ the UPS will automatically restart when the mains returns
- if set ‘off’ a manual restart is required, as in 4.2.1.
As default the ‘auto restart’ function is ‘enabled’. The setting can be changed using the UPS monitoring software. For
more information please refer to the manual that came with the software.
4.4.5 Battery low (end of runtime)
If during ‘on battery’ operation the 25% LED starts blinking, the batteries are nearly discharged: the remaining runtime is less
than 2 minutes (default setting, adjustable via the UPS monitoring software). Controlled shutdown of any computer
equipment is absolutely necessary at this point.
If the UPS operates at 100% load, the shutdown procedure should be completed within 2 minutes after the 'battery low'
alarm started. If only part of the output capacity of the UPS is used this period can be longer, with aged batteries this period
can be shorter.
When the batteries are fully discharged, the UPS is no longer able to power the connected equipment.
4.4.6 Bypass out of limits
The mains voltage or mains frequency are outside bypass input tolerance but inside UPS input tolerance (see section 8).
Bypass operation is inhibited: if for whatever reason the UPS is not able to deliver the required output, output power is lost. If
the input frequency is often out of tolerance – during which bypass operation is inhibited and an alarm is generated – it may
be useful to disable the bypass function after which the unit operates as a UPS without automatic bypass switch. See 4.5.
4.4.7 Overload
The demanded power exceeds the normal capacity of the UPS. The alarm occurs when the load is > 100%. If the load
exceeds 150% the UPS will immediately switch to bypass, assuming that the conditions for a transfer to bypass are fulfilled.
If an overload condition between 110-150% persists, the UPS will also switch to bypass operation.
During an overload the UPS may automatically switch off within a few minutes (load dependent) and output power is lost:
 if a transfer to bypass is inhibited (see 4.4.6), or