Toshiba 1700 - Manual (Page 34)

TOSHIBA
34
Appendix D: Parallel Operation
The 1700 Series Rackmount UPS offers a standard feature that allows
the unit to operate with very low input voltage without de-rating the
output power. If the input voltage drops below a certain point the unit will
switch to parallel mode. Parallel mode means that the unit is using the
available input voltage and supplementing with battery power. Because
battery power is being used, the time the unit can operate in parallel
mode is limited. However, the time will be longer than that available
when the unit is operating on battery power alone. The point when the
UPS will enter parallel mode will vary depending on the output load. The
following graph shows the various stages based on full output load and
75% output load.
As shown by the graph the lower the output load the lower the input
voltage can go before parallel mode is activated. However, the minimum
input voltage will always remain at 50% (60VAC for a 120VAC system).