GE GT Series User Manual

Also see for Digital Energy GT Series: User manual User manual User manual

Contents

4.4.1 On bypassThe UPS is equipped with an automatic bypass switch. This switch automatically transfers the load to themain power supply if the UPS is unable to deliver the demanded output power due to overload or overtemperature. If all 5 load LED are illuminated, bypass operation is caused by an overload. If only firstruntime LED is illuminated, bypass operation is caused by over temperature (see 4.4.8 tab .1).The UPS will switch back to normal operation when the overload has been removed. When temperaturedrops below alarm level unit can be switched back to normal operation. If a power failure occurs duringbypass operation, the UPS will switch to battery if possible, otherwise output power is lost.4.4.2 On batteryIn normal operation conditions, if a main power supply failure occurs, the UPS uses the energy stored inthe batteries to supply the load. The runtime capacity LED bar will show the remaining time (see 4.1). Forfurther information about runtime refer to chapter 9, Battery runtime. The UPS will shutdown:• After the batteries have been discharged (automatic restart if enabled), or• If keypad ‘UPS off’ is pressed (restart via front panel required), or• If a ‘UPS shutdown’ command is given by the computer (via UPS monitoring software). Restartdepends on the setting of “auto-restart” function (see 4.4.12).4.4.3 Battery low (end of runtime)If during battery operation the buzzer starts beeping every 5 seconds and the first LED of the batteryruntime bar starts blinking the batteries are nearly discharged: the remaining runtime is less than 2minutes (default setting, adjustable via the UPS monitoring software). Controlled shutdown of anycomputer equipment is absolutely necessary when this alarm is raised.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 nolonger able to supply the connected equipment and eventually output power is lost.4.4.4 Bypass out of limitsThe mains voltage or mains frequency is outside bypass tolerance but inside UPS input tolerance (seechapter 9). Bypass operation is inhibited: if for whatever reason the UPS is not able to deliver the requiredoutput, output power is lost. If the input frequency is often out of tolerance – during which bypassoperation is inhibited and an alarm is generated – it may be useful to disable bypass function (via UPSmonitoring software) after which the unit operates as a UPS without automatic bypass switch.NOTEThe unit can be used as frequency converter: the input frequency range is40-70 Hz; the output frequency is selectable 50/60 Hz, via UPS monitoringsoftware. If the unit is used in this configuration, the bypass function is nolonger available.4.4.5 OverloadThe demanded power exceeds the nominal capacity of the UPS. The “overload warning” alarm occurswhen the load exceeds 150% the UPS will immediately switch to bypass, assuming that the conditions fora transfer to bypass are fulfilled.If an overload condition between 110-150% persists, the UPS will also switch to bypass operation. In bothconditions the “overload” alarm (see 4.4.8 tab. 1) is generated. During an overload the UPS mayautomatically switch off within a few minutes (load dependent) and output power is lost:• if a transfer to bypass is inhibited (see section 4.4.4), or• if the bypass function has been disabled (see section 4.4.4), or• if the UPS operates on battery (see section 4.4.2).To avoid these problems, be absolutely certain that the power demand of the protected equipment iswithin the limits of the UPS.modifications reserved 28 User manual GT Series 5/6/8/10 kVA UPS 1.0 (US)