motor, and all leads from each individual transformer shall be brought out
to terminal blocks. They shall be of the dry or compound-insulated type
and shall be provided with a suitable means of mounting and for grounding
the frame. Each current transformer secondary lead shall be connected to a
terminal block of the short-circuiting type and shall be conveniently
located to permit short-circuiting the secondary windings without requiring
access to the primary bus compartments. The polarity of the current
transformers shall be plainly marked. [Each motor shall be provided with
three indoor dry-type window transformers with single secondary and rated
[50/5 amperes, 600 volts] [_____]. Current transformers shall have minimum
full-wave insulation level of 10 kV and, when installed, shall meet the
requirements for a [60 kV] [_____] basic impulse level (BIL). The
transformers shall be mounted in the main terminal box and shall be
arranged in the "flux-balancing" connection.] [Each motor shall be
provided with three current transformers of rated [4,160] [_____] and [60
kV] [_____] basic impulse level (BIL). The transformers shall be mounted
in the main terminal box and shall be connected in the wye point of the
winding for use with differential relays.] All current transformers shall
be suitable for continuous operation at the full-rated voltage and current
at a frequency of 60 Hz. All current transformers shall be designed to
withstand, without damage, the thermal and mechanical stresses resulting
from short-circuit currents corresponding to ratings of the breakers in the
circuits to which they are connected.
2.8
ACCESSORY WIRING AND BOXES
Except for current transformer leads and field control leads, all accessory
wiring shall terminate in an accessory terminal box, unless otherwise
approved by the Contracting Officer. Boxes shall be drip-proof and treated
in the same manner specified for frames to resist corrosion. The accessory
terminal box shall be furnished with a door hinged full length and shall be
mounted on the motor in a location approved by the Contracting Officer.
Rigid galvanized steel conduit shall be used wherever practicable and shall
be arranged to make removal unnecessary when the motor is dismantled. A
wiring diagram within the enclosure shall be provided for all circuits and
each conductor shall be identified with the designation shown on the
diagram. All wiring shall terminate on terminal blocks as specified below.
2.8.1
Wiring
Except as otherwise approved, all wiring shall be 125 degrees C rated
flexible copper conductors, No. 14 AWG minimum, with 600-volt insulation.
The size and type of temperature detector leads may be in accordance with
the manufacturer's standard practice and, where required, shall be suitable
for contact with lubricating oil. Each detector shall be connected by
three leads to terminal blocks, with one wire connected to a common point
on the blocks. The common point for the stator detectors shall be separate
from that for the bearing detectors.
2.8.2
Terminal Blocks
All terminal blocks shall be molded closed-back type as defined in NEMA ICS
4, rated not less than 600 volts and shall be provided with covers. The
terminals shall be screw-clamp type or stud-and-nut type. White or other
light-colored marking strips, fastened by screws to the molded sections at
each block, shall be provided for circuit designation. Each connected
terminal of each block shall have the circuit designation or wire number
permanently marked on a strip. Reversible or spare marking strips shall be
furnished with each block and at least 10 percent spare terminals shall be
SECTION 16222A
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