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KESS Power Solutions Gmbh / www.kess.at / info@kess.at
7.8 oPERATioN of AN UPS wiTh A PARALLEL SySTEM oR A SiNGLE UPS
(ModELS 4 To 6 KVA)
To operate the parallel system, it is necessary to have a manual bypass box for
the parallel system. if there is none, you have to shut down the whole system and
the connected loads.
The following steps are meant to add a device in a system with two units. To
incorporate a device into a system with only one UPS, proceed in the same way.
The fuse box must have input and output switches for each UPS, in
addition to the one for the manual bypass. otherwise, it will be necessary to
adapt the box or acquire a new one if it has not been previously anticipated.
Since it is necessary to change the parallel bus connection to incorporate the
new device into the system (cable with db15 connectors), it will be necessary
to switch the powering of the loads to the manual bypass. Proceed as follows:
•
Press the ‘off’ button on all of the UPS devices for more than 2 seconds to shut
down the inverter in all of them. The audible alarm will sound for 1 second. The
devices, that make up the current parallel system, will switch to ‘bypass mode’.
•
Switch the devices to manual bypass using the following procedure: Remove
the mechanical lock on the manual bypass switch or disconnector of the fuse
boy and turn it to ‘on’. Remove the protective cover of the manual bypass
switch, which is located at the back of each unit, and turn all of the switches to
‘bypass’. Consider that in ‘bypass mode’ the loads are exposed to voltage and
frequency variations and cuts or micro-cuts in mains power. if it is possible, it is
recommended to choose a day with lower probability of failure (days without
fluctuations, days without storms, etc.) and a certain speed in the process.
•
Turn the input circuit breakers of each device to ‘off’.
•
Turn the input and output circuit breakers of the box to ‘off’.
•
before incorporating the new KESSUPS 92RT into the system, carry out the
appropriate steps to leave it in the same condition as the others (input switch
turned to ‘off’ and manual bypass switch without protective cover turned to
‘bypass’).
•
incorporate the new UPS to the system following the procedure established in
section 6.13 for connection in parallel.
• Disconnect the communication bus between the first and last device, and
reconnect it including the new UPS. The bus must be closed for proper
operation.
•
Turn the input circuit breakers of each UPS on the fuse box to ‘on’.
•
Turn the input circuit breakers of each UPS to ‘on’.
•
The output switches of each UPS on the fuse box must be opened. The UPS
supplies ouput voltage from the internal static bypass of each unit. Check
if the LCd monitor shows any warning or error information. Measure the
output voltage at the terminals of each UPS seperately to check if the voltage
difference is greater than 1 V. if the difference is greater than 1 V, then check
the connection plans and follow the instructions.