Liebert PDUTM, STS2 manual Access, Circuit Breakers, Cable Entrance, Doors, Color Graphical Display

Specifications

14.2.4Access

The STS2/PDU is designed so repairs and maintenance can be done from the front, side or top of the unit. All components that may need repair or replacement during routine field maintenance are safely accessed with the units in bypass without removing power from the unit. These components include:

•All electronic PCB assemblies

•Power supply assemblies

•All control fuses

•All circuit breaker plug-in modules

•Fans

•SCRs

All power connections are designed to maintain proper connection torque over the lifetime of the unit without any maintenance. The integrity of the connections can be checked via infrared scanning safely from the front or top of the unit.

All other components including transformers, power cables and connections, circuit breaker bases, etc., are replaceable from the front, rear or top of the unit, but this requires all power to be removed from the unit for safety. Although routine re-torquing of the power connections is not required, if maintenance of these connections is needed, complete removal of power is required from the unit for safety reasons.

! WARNING

Lethal voltages exist inside the unit during normal operation. Only qualified service personnel should perform maintenance on the Static Transfer Switch 2 Power Distribution Unit.

The unit is supplied by more than one power source. The unit contains hazardous voltages if any of the input sources is on, even when the unit is in bypass. To isolate the unit, turn off and lock out all input power sources.

Verify that all input power sources are de-energized and locked out before making connections inside unit.

14.2.5Circuit Breakers

The STS2/PDU is equipped with two input plug-in circuit breakers and five or six (if CB3A is used) molded-case, plug-in, non-automatic circuit breakers. The breakers are UL listed for use up to 600VAC and CE marked. The plug-in feature of the breaker includes an interlock, which prevents the breaker from being unplugged without being in the OFF (open) position.

Mechanical interlocks are provided on the breakers to prevent improper maintenance bypassing of the solid-state switch. A bypass breaker cannot be closed unless the solid-state switch is connected to the same input source and only one bypass breaker can be closed at a time. All breakers are equipped with N.O. and N.C. auxiliary switches for monitoring of the breaker positions. The two solid-state static switch input breakers are equipped with 48 VDC shunt trips to allow for control by the STS2/ PDU logic. See Tables 9 through 11.

14.2.6Cable Entrance

Removable conduit termination plates are provided in the top and bottom of the STS2/PDU for termi- nation of the two source input conduits or raceways and/or the output conduits or raceways. On units with inline panelboards, output conduit or raceways are bottom exit only.

14.2.7Doors

A removable key lock hinged front door provides access to the circuit breakers.

14.2.8Color Graphical Display

The display is located in the front of the unit. Front panel display is an LCD touch screen display for monitoring and configuring the unit. See Figure 57 for a drawing of the touch screen display.

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