19. Optional MB (Maintenance Bypass) Units
The following illustration shows the circuit power flow when the UPS is operating in the optional Mainte- nance Bypass mode. The input jumper on the UPS must be set for 240 VAC.
NOTICE
Ensure the UPS is in Static Bypass before switching the unit from UPS to Maintenance Bypass mode or from Maintenance Bypass to UPS mode. Failure to do so could result in damage to the maintenance bypass switch or the UPS.
This Maintenance Bypass unit can only be used for 240 V applications. Ensure the UPS voltage selector jumper is set to 240 V. See page 12 for the correct 240 V setting.
Bypass
*Static Switch
Maintenance
Bypass Switch
Input Power
MCCB
Line Filter
Surge
Absorber
Input
Fuse
Rectifier/
Chopper
Batteries 
+
–
Negative
Bus
Output
Fuse
Inverter
* Switches are solid state devices.
Isolation
Transformer
Output
Power
Power Flow
POWER FLOW IN MAINTENANCE BYPASS MODE FOR ALL MODELS
19.1 Internal Maintenance Bypass
The optional internal maintenance bypass is mounted on the rear of the UPS.
Internal Maintenance Bypass Instructions:
From Inverter Mode to Maintenance Bypass Mode
1.Turn the RUN/STOP switch to the STOP position on the UPS.
2.Turn the Maintenance Bypass Switch to the Bypass position. The Bypass LED should be ON and the UPS LED should be OFF. The LEDs are next to the Maintenance Bypass switch, on the back of the UPS.
3.Turn the MCCB input breaker on the UPS to the OFF position. The UPS is now operating in Mainte- nance Bypass Mode.
From Maintenance Bypass Mode to Inverter Mode
1.Turn the MCCB input breaker on the UPS to the ON position.
2.Turn the Maintenance Bypass switch to the UPS position. The UPS LED should be ON and the Bypass
LED OFF.
3.Turn the RUN/STOP switch to the RUN position on the UPS. The UPS is now operating in the UPS Mode.
42 | 1600XP Series Installation and Operation Manual |
