SMARTZONE UPS USER MANUAL
32
Note:
Output short circuit protection is not supported in the internal Bypass state. A short circuit
on the output at this time could damage the UPS.
Switching the 3-Phase UPS to the Maintenance Bypass state (with the
optional Maintenance Bypass Switch Unit - MBS):
1. Make sure that the MAINTENANCE breaker and OUTPUT breaker signals are
properly connected from the MBS to the UPS.
2. Remove the locking cover plate over the MAINTENANCE breaker (on the MBS).
Te UPS automatically switches to the internal Bypass state.
3. Switch ON (from down to up) the MAINTENANCE breaker on the MBS that
bypasses the UPS unit.
4. Turn OFF the Battery breakers on the EBP(s) connected to the UPS.
5. Switch OFF (from up to down) the MAINS breaker on the MBS that feeds the
input to the UPS unit.
6. Switch OFF (from up to down) the BYPASS breaker on the MBS that feeds the
input to the UPS unit.
7. Switch OFF (from up to down) the OUTPUT breaker on the MBS from the output
of the UPS unit.
8. At this point the UPS is totally isolated from the system and the MBS source is
supplying power to the load through the MAINTENANCE breaker.
Note:
Wait for about 30 minutes for the internal DC bus capacitors to be completely discharged,
before opening the UPS enclosure for period maintenance by qualified personnel.
Switching the 3-Phase UPS to Normal Mode from the Maintenance
Bypass state through the MBS
Note:
Never attempt to switch the UPS back to Normal Mode until it is verified that there are no
internal UPS faults.
1. Switch ON (from down to up) the OUTPUT breaker on the MBS to connect the
output of the UPS unit to the load.
2. Switch ON (from down to up) the BYPASS breaker on the MBS to connect the
input source to the input bypass on the UPS unit.
3. The UPS starts powering the load from the internal Bypass in parallel with the
Maintenance Bypass and the bypass LED on the UPS will turn ON.
4. Switch ON the Battery breakers on the EBP(s) connected to the UPS.
5. Switch ON (from down to up) the MAINS breaker on the MBS to connect the
input source to the main input on the UPS unit.
6. Switch OFF (from up to down) the MAINTENANCE breaker on the MBS. The
load is fully supplied by the internal Bypass of the UPS unit.
7. Reinstall the cover plate on the MAINTENANCE breaker.