Section III
Operation
006-0007129 10/12/2018
Rev B
24 of 60
UPS-1500 3-Phase Guide
www.synqor.com
Power Cable Connections/Disconnections While Operating
For safety reasons, it is highly recommended that the input and output power cables be
connected to the UPS before the source of AC or DC INPUT power is turned “ON”, and before
the UPS is turned “ON” (see Section I: Warnings and the SET-UP section above). Similarly, it is
highly recommended to first turn “OFF” the UPS and any active input sources before any power
cables are disconnected from the UPS.
However, the SynQor UPS is capable of having any of its input or output power cables connected
at any time (if safely done), including while the UPS is turned “ON” and delivering power to the
load. For instance:
• Even if the UPS is turned “ON”, one can connect or disconnect the input power cables without
harming the UPS or disrupting power delivery to the load. If no INPUT power source is available,
the UPS will draw power from the battery pack. When there is an external source of power
connected to the UPS, the unit will draw power from that source. The UPS will always select as
its primary power source the AC INPUT, if present and if all phases are within range. The DC
INPUT source will be selected as an input source only, if no AC INPUT is present or if the AC
INPUT is not within input specifications. Switching INPUT source from AC, to DC to battery is
carried out seamlessly and glitch free by the UPS internal control system.
• Even if the UPS is turned “ON”, one can connect or disconnect an output power cable without
harming the UPS or disrupting power delivery to a load that might be connected in one of
the other output connectors.
NOTE that disconnecting an input or output power cable while that cable is handling power will likely
cause an arc to form as the terminals are pulled apart. This arcing is not harmful to the UPS, although
if done enough times it will degrade the connector to the point where it will need to be replaced. This
problem is particularly acute for the DC INPUT cable because of its high current. Disconnecting this
cable while a large current is flowing is not recommended.
ALSO NOTE that when the UPS is turned “ON” and delivering power to a load, and then another piece of
equipment is connected to the same output, it is possible that this connection will momentarily disrupt
the quality of the UPS’s output voltage. For instance, consider the case where the AC OUTPUT power cable
has a terminal strip that allows several loads to be connected. If the UPS is turned “ON” and delivering
power to several loads, and another load is turned “ON”, it is possible that the new load will momentarily
draw a large surge of current at startup. If this happens, the output of the UPS could momentarily reach
its maximum current limit, which will cause the UPS to reduce its output voltage to keep the current
from getting any larger. The reduction in voltage will be corrected once the new load reaches normal
operation. However, in the meantime the reduction of the UPS’s output voltage might cause one or more
loads to malfunction. Whether or not this will be a problem depends on the characteristics of each of the
various loads.