Emerson Liebert NX 50 and 60 Hz - Manual (Page 117)

Options—For Assembly Inside the UPS Cabinet
105
9.0 O PTIONS —F OR A SSEMBLY I NSIDE THE UPS C ABINET
Several items of optional equipment are available for connection to the Liebert NX UPS. These are
described in this section of the manual and should be fitted prior to installation.
9.1 Protection
9.1.1 Redundant Back-Feed Protection
In addition to the dry output back-feed protection contact provided for tripping of an external circuit-
breaker upon a shorted static bypass semiconductor condition (refer to 1.8.4 - Output Dry Con-
tacts), an optional contactor can be fitted in series with bypass semiconductors (SCR) in order to pro-
vide air-gap isolation between upstream of the UPS input bypass mains and the Inverter output. The
power supply to the coil of contactor is taken from the bypass mains input line voltage. When the
bypass mains input is unavailable, the contactor is opened and the UPS is disconnected from the
bypass mains supply.
9.1.2 Seismic Anchors
Seismic anchors avoid or lessen the damage caused by a possible earthquake or vibration and ensure
that the UPS does not overturn or move laterally under such a situation.
The Seismic Anchor classification when bolted into a suitable concrete slab, exceeds the requirements
of Level 2, Table 2 IEC60068.3.3 and complies with UBC 1994, Seismic Zone 4 for strong to very
strong earthquakes
9.1.3 Degree of Protection for the UPS Enclosure
The standard degree of protection is IP20. A canopy option for IP21 is also available.
9.1.4 Battery Start Facility
The battery start kit consists of controls, a push button, a charging resistor and an internal battery
contactor that replaces any end of discharge battery circuit breaker trip control. The battery is perma-
nently connected to the UPS DC input.
Table 25 Seismic anchor sizing
UPS
Anchor Width
mm (in)
Anchor Length
mm (in)
30-120kVA 500 (19.7) 83 (3.3)
140-200kVA 750 (29.5) 83 (3.3)