1
INSTA LL ATION INSTRUC TIONS
Servicenter
™
mini-unit substation
Three-phase 22.5 kVA models
Receiving
Upon receipt of shipment, examine the
package for any damage that may have
occurred in transit. While unpacking,
examine the unit for broken, bent, loose
parts, or other damage. If injury from
outside sources is evident, file a damage
claim with the transportation company
and notify the nearest sales office.
Storage and handling
The storage area should be clean. Before
placing the unit in service after a period of
storage, be sure it is clean and dry by
observing the instruction under
“Installation”. The unit may be fork truck
lifted or raised by the lifting holes located
on the top core clamps under the
transformer cover.
Installation preparation and mounting
If the interior moisture is evident by the
appearance of rust, the unit should be
dried. Megger readings of 10 Megohms
minimum should be obtained before
installation. Free circulation of air is
essential for proper operation of the unit.
The servicenter will perform at its rated
output when surrounding air does not
exceed 40 °C (105 °F) and adjacent
structures permit free movement of
cooling air. The unit must be mounted
upright.
Connections
NOTE: Do not make or change
connections while unit is
energized!
The unit must be mounted upright.
Reference should be made to the wiring
diagram (Figure 1) when making
connections.
A new grounding electrode conductor is to
be connected to the neutral bar of the
secondary in accordance with the National
Electrical Code.
If a primary terminal strip is bonded to the
enclosure by means of the neutral bonding
screw, it may be removed for special
applications.
Make certain that all connections are
electrically tight to prevent joint heating.
If aluminum cable is used, adequate
preparation of the aluminum cable and
protection of the joint is essential.
Secondary branch circuit breaker ampere
ratings and branch circuit conductor sizes
must be selected in accordance with the
National Electrical Code.
The servicenter is factory connected on
the primary side for the nominal rated
three-phase delta connected input
voltage. If the primary input voltage is
other than nominal, the transformer taps
may be adjusted in accordance with
instructions provided with the
transformer.
The primary main breaker and the
secondary main breaker may be changed
using breakers of equal voltage ratings
and “equal to” or “lower” current ratings.
However, the use of primary breakers with
current ratings lower than those supplied
may result in nuisance tripping. This is due
to in-rush currents in the primary winding
which occur when the transformer is
energized.
NOTE: Primary and secondary
breakers with current ratings
higher than those supplied must
not be used.
After all electrical connections have been
made and the required branch circuit
breakers installed, the inside metal cover
plate must have the corresponding branch
circuit breaker knockouts removed and
the cover-plate reinstalled. Fasten the
cover-plate in place, being sure that no
cables are caught between the cover-plate
and the framework. Also, ensure that all
breakers are aligned with the knock-out
holes in the cover-plate. Branch circuit
positions should be recorded on the
identification labels provided.
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Servicenter mini-unit substation
