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the resistor has a short circuit. If the voltage difference is more than 1V, the output relay of
the UPS may have problem and can not be closed.
11. Measure the voltage between JP2s of each UPS (JP2 of Unit I-JP2 of Unit II, and so on) to
check if the voltage value is less than 5V (Generally 2V). If the difference is more than 5V.
You need to check that whether the parallel cable or the parallel board is ok.
12. Measure the inverter output voltage between JP2 and input neutral on each UPS, the
inverter output voltage of each UPS should be as close as possible, if the voltage
difference higher than 1V, please execute a calibration process.
13. Turn off all of the UPS systems that are running. After all of them have transferred to the
bypass mode, disassemble the maintenance cover of each UPS and turn the maintenance
switch from “BPS” to “UPS” and screw the maintenance cover right back.
14. Turn on the UPSs and the system should work in parallel operation.
5.3.2.2 Operating procedure of adding a new UPS to the parallel system
1.
Prepare the input and output cables, the input/output breaker (switch) and the parallel
cable.
2.
Keep the input and output switch of the UPS to add in the off position. Connect the input
and output cables as well as the battery pack according to the marking on the terminal
block. Remove the short connection wire between JP1 and JP2 on the terminal block.
3.
Turn off the UPS that are currently running. After all of the UPSs that are running transfer to
the Bypass mode go to the next step.
4.
Disassemble the maintenance bypass switch cover of each UPS (including the one to add )
and turn the maintenance bypass switch from “UPS” to “BPS” state, then switch off the
input breaker on rear panel of each UPS.
5.
If the UPS system that is running is single UPS, you need to remove the short connection
wire between JP1 and JP2 on the terminal block.
6.
Disassemble the cover of the parallel port on the new UPS, plug one end of the parallel
cable into parallel communication port and screw the connector; the other end of the
parallel cable is connected to parallel communication port of the working UPS, screw the
connector, and screw covers of the parallel port of all UPSs.
7.
Turn on the mains input breaker of the new UPS; Measure the voltage difference between
the output line wires in the new UPS and the parallel system. If the difference is more than
