American Power Conversion MatrixTM UPS - Manual (Page 5)

3. Presentation
3.1 Isolation Unit (IU)
Rear View of Isolation Unit
1. Isolation Unit (IU)
The Isolation Unit contains the UPS’s isolation transformer, EMI/RFI and surge suppression, bypass circuits including
an auxiliary power supply, and utility and load wiring interfaces. The IU is capable of autonomous operation and allows
service of the Electronics Unit without interruption of power to the load.
2. Input circuit breaker (power ON / OFF)
The input circuit breaker controls power to the UPS. It protects the UPS and the service wiring from extreme overloads.
3. Cooling fan
The fan exhausts air from the IU and operates whenever the input circuit breaker is ON (I). If the fan fails, the UPS will
indicate an alarm condition. Under such conditions, the UPS will remain operating and is capable of delivering full
power to the load.
4. EU separating screw
The Electronics Unit separating screw is turned counter-clockwise to remove the EU for service. If this action is taken
while the UPS is on-line, the UPS will automatically transfer to bypass operation. See the Difficulty section of this
manual for the proper EU replacement procedure.
Note: The UPS’s display is blank when the EU separating screw is loosened. Control of the UPS is regained when the
screw is tightened and any control button is pressed.
5. Power distribution plate
The power distribution plate is removable for access to the input voltage selection taps. Optional Power Distribution
Unit (PDU) accessories are available from the factory with wiring devices other than those provided on the power
distribution plate. These PDU accessories are plugged into either a NEMA L6-30R receptacle 208 Vac output, or the
NEMA L14-30R receptacle 120/240 Vac output.