6 Use and Operation
MY-A Series (10kVA-20kVA) UPS
User Manual
88
breaker of paralleled UPS, measure the circulating current of parallel UPS, and the current should be
less than 3A.
When the voltage different larger than 8V, measure the output voltage of the UPS and check if the
output are all 120V, if the voltage different larger than 15V, please report it to our company to
maintain it. In addition, once the circulating current of parallel UPS too large, it will lead to the
inverter fault. If the circulating current is larger than 3A, please report it to our company to maintain
it.
Step 3
Switch on the total output breaker of UPS, each output branch breaker, and then start the load one by
one.
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6.4.2 Shut Down Parallel System
Generally, it isn't recommended to start or close parallel system frequently.
Step 1
Shut down all load.
Step 2
Shut down parallel UPS one by one.
Step 3
Switch off the related breakers of each UPS (when daily use, the breakers can be not closed).
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6.4.3 Exit Parallel System
When one UPS in parallel system fault, it will exit from parallel system automatically with sound &
light alarm. At that time, perform the operations shown in Figure6-1, the fault UPS will be exited
from parallel system completely to achieve online hot maintenance or replacement.
Switch off breaker of input, bypass,
battery and output, which connects
with the faulty UPS.
Close the fault UPS
according to shutdown
procedures.
Figure6-1
Exit parallel system
When the parallel system works normally, it's better not to exit the output from parallel system before
the UPS closed, or the power system will be abnormal.
