ARRANGEMENT
DESCRIPTION OF
SWITCH POSITION
#
SWITCH
LINE A SW
LINE B SW
XFMR SW
ARRANGEMENT
OPEN CLOSE
OPEN CLOSE
OPEN CLOSE
lines connected to
transformer
_____________________________________________________________________
2
Transformer connected
X
X
X
to Line A only
_____________________________________________________________________
3
Transformer connected
X
X
X
to Line B only
_____________________________________________________________________
4
Transformer open and
X
X
X
loop closed
_____________________________________________________________________
5
Transformer open and
X
X
X
loop open
_____________________________________________________________________
2.9.2.3
Transformer Tank Sections
**************************************************************************
NOTE: For 480Y/277 volt secondaries, 2 primary taps
above and 2 primary taps below are standard. For
208Y/120 volt secondaries, 4 primary taps below are
standard. Normally, the design should use standard
having adequate interrupting ratings. ANSI
C57.12.26, Table 2, lists 5.75 percent for 750 kVA -
2500 kVA. For 75 kVA - 500 kVA, use manufacturer's
standard.
**************************************************************************
Transformers shall comply with IEEE C57.12.00, ANSI C57.12.21, and ANSI
C57.12.26 and shall be of the [mineral oil-insulated type] [less-flammable,
liquid-insulated type with [high molecular-weight hydrocarbon] [or]
[dimethyl silicone] liquid]. Transformers shall be suitable for outdoor
use and shall have 2 separate windings per phase. Standard NEMA primary
taps shall be provided. Where primary taps are not specified, 4, 2-1/2
percent rated kVA high-voltage taps shall be provided [2 above and 2 below]
[below] rated, primary voltage. Operating handles for primary tap changers
for de-energized operation shall be located within high-voltage
compartments, externally to transformer tanks. Adjacent to the tap changer
operating handle, a nameplate or equivalent stenciled inscription shall be
provided and inscribed "DO NOT OPERATE UNDER LOAD." Transformer ratings at
60 Hz shall be as follows:
Three-phase capacity.....................................[_____] kVA.
Impedance....................................................[_____].
Temperature Rise........................................65 degrees C.
High-voltage winding...................................[_____] volts.
SECTION 16375A
Page 34