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HT33 Series User Manual
Note
In bypass mode, the load is directly fed by the mains power instead of the pure AC power from the
inverter.
5.3.3 Procedure for Switching the UPS into Normal from Bypass Mode
Select “exit bypass mode” on the LCD, about 3 seconds later, UPS transfer to inverter mode
automatically.
5.3.4 Procedure for Switching the UPS into a Maintenance Bypass from Normal Mode
In normal operation, this operation instruction will switch the load from inverted input to maintenance
bypass.
Caution
Before making this operation, read messages on display to be sure that bypass supply is regular and
the inverter is synchronous with it, so as not to risk a short interruption in powering the load.
1. Switch UPS from normal mode to bypass mode according to 5.3.2.
The inverter indicator and status indicator go off, the buzzer alarms. The load will be transferred to
static bypass, and the inverter is closed.
2. Remove anti-misoperation stop plate for rotary air switch, then the rotary air switch is switched to the
maintenance bypass side in order that the load power supply is supplied by the maintenance bypass,
and the mains switch Q1, the bypass switch Q2, the output switch Q4 and the internal and external
battery switches are disconnected.
Warning
If it is required to mainten the modules, the cabinet is opened for internal maitenance after waiting for
10 minutes in order that the capacitor voltage in the internal DC bus automatically dischages.
5.3.5 Procedure for Switching the UPS into Normal from a Maintenance Bypass Mode
This procedure can transfer the load to normal main mode when the UPS is operating under the
maintenance bypass mode.
1.
Close the bypass switch Q2 and switch the rotary switch to “UPS output” side.
The indicator light of the bypass become green and the power is supplied for the load by the
bypass.
2.
Close the mains input air switch Q1
The power is supplied for the load by the bypass. At the same time, the rectifier begins to operate,
the indicator light of the rectifier become green after 30 seconds, and the power is automatically
supplied with the inverter after 2 minutes.
3.
Close internal and external battery switches. If the indicator light of the battery does not work,
please confirm the voltage of the LCD display battery is normal.
4.
Replace the anti-misoperation stop plate for rotary switch.
5.4 Procedure for Completely Powering down a UPS
If you need to power down the UPS completely, follow the procedures in section 5.3.4 to transfer the
UPS from normal mode to maintenance bypass mode.
If you need to isolate the UPS from the AC power supply, you should open the external input switch.
