2.1.7.2
Stator Coils
The coils shall be thoroughly insulated and treated with a moisture and
fungus-resisting compound in such a way that air will be excluded and the
insulation will be protected from the absorption of moisture. Additional
insulation shall be provided for those portions of each coil which are
within the slots. The coils shall fit the slots accurately and they shall
be form wound and interchangeable. The end turns shall be so designed and
supported that they will not be distorted under the most severe
short-circuit conditions to which the motor may be subjected.
2.1.7.3
Insulated Stator Windings
The stator windings shall be insulated as specified in paragraph GENERAL
REQUIREMENTS. Coils shall be of such uniformity that the stator windings
of all similarly rated motors will be alike, in shape and size, and
interchangeable. The stator winding and end turn connections shall be
fully braced to withstand repeated full voltage starts. The bracing system
shall essentially eliminate coil vibration under these high current
conditions as well as during normal operation. A tieless bracing system
will be acceptable. If a tied system is used it shall be such that no tie
depends upon the integrity of any other tie within the system.
2.1.7.4
Temperature Detectors
Six standard copper resistance-type temperature detectors, with a
resistance of 10 ohms at 25 degrees C75 degrees F, shall be provided in the
stator in accordance with NEMA MG 1 paragraph 20.63. Detectors shall be
wired in accordance with paragraph ACCESSORY WIRING AND BOXES.
2.1.7.5
Grounding
The stator frame shall have provisions for solidly grounding to the station
ground system which will be furnished and installed by others.
2.1.8
Rotor
The rotor shall be built in accordance with the best modern practice and in
such a manner as to secure adequate strength for the operating conditions
described herein. The pole pieces shall be built up of thin steel
laminations accurately aligned and securely riveted or bolted together. It
is preferred that the field poles be secured to the rotor structure by
means of dovetails, but an alternate method of construction will be
acceptable, provided that evidence of its adequacy, satisfactory to the
Contracting Officer, is submitted with the bid.
2.1.8.1
Field Windings
The field windings shall be insulated as specified in paragraph GENERAL
REQUIREMENTS. The field coils shall be adequately insulated between turns
and from the pole pieces and shall be thoroughly braced to withstand the
stresses which could be imposed under maximum pump speed.
2.1.8.2
Starting Windings
The starting windings shall be designed for full-voltage starting, securely
built into the field poles and designed to ensure conservative stresses
when the unit is operating at maximum pump speed. The bars shall be silver
soldered or brazed to heavy end segments to form a low-resistance joint of
SECTION 16222A
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