OnLine Power Power Wave 4 - Manual (Page 51)

6005-145 Rev. A 4-4
(c) Open the rectifier breaker – Opening the rectifier breaker will take the power
source away from the DC bus, causing the DC bus to drop slowly. After 5 min.,
the DC bus will drop to a safe level (<20VDC).
(d) Close the bypass breaker – The reserve breaker and reserve static switch are still
conducting. Therefore, when the maintenance bypass breaker is closed, power
will flow through the bypass loop instead of the reserve loop because of the lower
impedance of bypass loop.
(e) Open the reserve breaker – You can now open the reserve breaker to free the ELI
from any power supply.
4.4. From Maintenance Bypass to Inverter Procedure
If the ELI is in maintenance bypass mode, and you want to turn the ELI to normal
mode without interrupting the output AC, please follow the steps below.
(a) Close the reserve breaker – The reserve and output LED on the mimic will light,
indicating the reserve static switch loop is energized, and the output has power.
The power supply in the ELI is also established, and the fans will operate.
(b) Open the bypass breaker – The inverter cannot be switched on while the
maintenance bypass breaker is closed (because the CPU will sense the breaker
and prevent the inverter from connecting directly to AC source). Since the reserve
breaker is already closed, power goes through the reserve loop if the bypass
breaker is open. Thus, AC at the output will not be interrupted.
(c) Close the rectifier breaker - The rectifier will be automatically started if the power
source connected is correct. Wait 30 sec for DC bus voltage to rise until the
warning LEDs of “BAT LOW” and “BAT LOW STOP” go off (on the front
panel). Now, the DC is already ready for the inverter.