Liebert Static Transfer Switch 2, Installation, Operation & Maintenance Manual

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Maintenance 135
17.0 M
AINTENANCE
Minimal periodic maintenance of the STS2 is required. As with all electrical distribution compo-
nents, the system should be regularly inspected for electrical connection integrity, signs of excessive
temperatures, dirt accumulation, and proper system operation.
17.1 Proper Tightening of Nuts and Bolts
The recommended tightening torque for all nuts and bolts is as shown below, unless otherwise
labeled. All power connections are designed to remain at proper torque throughout the lifetime of
the unit.
17.2 Testing the STS2
The STS2 includes comprehensive system alarms and fault detection to identify operational prob-
lems. To increase the degree of confidence of proper system operation, periodic transfer tests can be
easily performed. For instructions for changing the preferred source and switching sources:
• For a Color Graphical Display unit, see Manual Transfer / Preferred Source Selection on
page 59 in 10.0 - Operating Instructions for the Touch Screen Interface .
• For a LED Display unit, see Manual Transfer / Preferred Source Selection on page 104 in
14.0 - Operating the LED Display STS2 .
17.3 Changing the Air Filter
A standard furnace filter is installed behind the air intake in the front door. The air intake allows
air to circulate to cool the unit. Replace the filter when it becomes dirty and impedes air flow. The
frequency of changing or cleaning the filter depends on the location in which the unit is located.
The size of the filter is 1 in. x 25 in. x 25 in. (2.54 cm x 63.5 cm x 63.5 cm).
!
WARNING
ONLY QUALIFIED SERVICE PERSONNEL SHOULD PERFORM
MAINTENANCE ON THE STATIC SWITCH.
LETHAL VOLTAGES EXIST INSIDE THE UNIT DURING
NORMAL OPERATION.
THE UNIT IS SUPPLIED BY MULTIPLE AC POWER SOURCES.
DISCONNECT AND LOCK-OUT ALL POWER SOURCES BEFORE
WORKING INSIDE UNIT.
Table 26 Torque tightening
Bolt Shaft Size
Grade 5 -Imperial
Grade 8.8 -metric Electrical Connections with
Belleville Washers
in-lb
(inch-pound)
N-m
(Newton-meter)
in-lb
(inch-pound)
N-m
(Newton-meter)
10-32 25 3 35 4
1/4-20 53 6 80 9.0
5/16-18 107 12 180 20.4
3/8-16 192 22 240 27.1
1/2-13 428 48 480 54.3