The Input/Output Cabinet provides the primary connections points for 3-wire AC connections to the UPS. The facility three-phase wiring is connected to the bus bars that are located above the K1 input circuit breaker.
3-wire power, regulated, or unregulated, leaves this cabinet via the K5 output circuit breaker.
In a 4-wire system there is no output from this cabinet. All output gets routed through to the 4-wire output cabinet.
When the system is in maintenance bypass mode via the Maintenance Bypass Cabinet, the 3-wire power is still output via the Input/Output Cabinet.
Cabinet Description
The Input/Output Cabinet is a 42-inch wide, two door units. The Input/Output Cabinet contains the following components:
- one or two 1600A or 2000A circuit breakers
Note: The circuit breakers on a 3-wire system are nominally rated at 1600A. The circuit breakers on a 4-wire system are nominally rated at 2000A.
- the input K1 and the optional output K5
- a set of input landing bus bars
- a set of output landing bus bars
Wiring
The Input/Output Cabinet is designed to allow for the facility wiring to enter through the top of the cabinet. The input bus bars and the output bus bars of the Input/Output Cabinet are designed to accommodate 500MCM wire through 750MCM wire. The number of wires are based on local codes and the size of the input facility circuit breaker.
The output side of the Input/Output Cabinet is unused when a 4-wire facilities output connection is located in the 4-wire Output cabinet.
Location
The Input/Output Cabinet is located to the left of the Static Switch cabinet.
Circuit Breakers
The circuit breakers on a 3-wire system are nominally rated at 1600A.
The circuit breakers on a 4-wire system are nominally rated at 2000A.
Input Circuit Breaker
The operating settings for input current trip limits are factory pre-set at 105 continuous operation and 125 percent maximum system overload. The input circuit breaker contains a 24VDC Undervoltage Relay which opens the circuit breaker when input power is lost.
Output Circuit Breaker Option
The output of the UPS can come in one of three configurations:
- No Circuit Breaker or Switch
- Circuit Breaker
- Motor Operated Circuit Breaker
The output circuit breaker is a manual device without the thermal magnetic trip internal to the casing.
The motor operated output circuit breaker configuration is required when the system has the Maintenance Bypass option.
The output of the UPS is interlocked with the maintenance bypass function to open and/or close the motor-operated output circuit breaker at appropriate times depending on the state of the maintenance bypass breaker.
Additional Components
Connected to the back of the frame where the doors close is a board called the Breaker Bell Alarm Supervisor. The function of the Breaker Bell Alarm Supervisor Board is to monitor the status of the K1 circuit breaker and K5 circuit breaker. The Breaker Bell Alarm Supervisor Board verifies that the K1 circuit breaker and K5 circuit breaker open only when a command is given.
A reset pushbutton is located behind the locked door that covers the K1 circuit breaker and resets the breaker lockout when the breaker has opened because of an over-current trip state.
Note: Before pressing the reset pushbutton, refer to Systems Operation, Testing and Adjusting, RENR7654, "K1 Overcurrent Shutdown - Reset".
At the back left side of the unit is a MOV surge protector and circuit breaker. These help filter the power by eliminating power spikes and surges.
Additional Options
Additional options for the Input/Output Cabinet include circuit protection for external Generator Set Starting battery-free 24VDC power-supplies that are connected to the protected the output of the UPS.
An External Source Synchronization option is available for this UPS and is integrated into the Input/Output Cabinet. This option allows the customer to synchronize the output of the UPS to another source.
Cabinet Diagrams
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| Illustration 1 | g01273887 |
Input/Output Cabinet - Left View with Shields (1) Vertical Frame (2) Right Panel (3) Left Shield (4) Breaker Bell Alarm Supervisor PWA (BBS) (behind frame) (5) Output Breaker K5 (Optional) (6) Input Breaker K1 (7) Reset Pushbutton (8) Left Panel | |
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| Illustration 2 | g01273890 |
Input/Output Cabinet - Left View (5) Output Breaker K5 (Optional) (6) Input Breaker K1 (9) Left Component Panel (10) Ground | |
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| Illustration 3 | g01273901 |
Input/Output Cabinet - Left Panel (11) GSM Breaker (1x GSM Option) (12) GSM Breaker (2x GSM Option) (13) Fuse Block F91-F93 (14) Fuse Block (MBP Option) F55, F56 (15) Fuse Block F11, F12 F17-F19 (16) Fuse Block F1-F3 F7-F10 (17) Terminal Block (ESS Option) (18) ESS PWA (ESS Option) (19) Fuse Block (ESS Option) F64-F66 | |
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| Illustration 4 | g01273902 |
Input/Output Cabinet Rear Panel (10) Ground (20) MOV Surge Protector (21) MOV Circuit Breaker (K10) (22) Wire Terminal | |