API St 547:2005 pdf download

API St 547:2005 pdf download.General-purpose Form-wound Squirrel Cage Induction Motors-250 Horsepower and Larger.
2.3.2 The insulation system shall be capable of withstanding the surge test specified in 4.3.4.
2.3.3 All stator insulation systems shall be service proven and shall have been subjected to thermal evaluation in accordance with IEEE 275.
2.3.4 The stator windings. including the lead connections, shall have a sealed insulation system that is capable of withstanding a scaled winding conformance test in accordance with NEMA MG I Part 20. The scaled insulation system shall be a proven design with temperature classification per IEEE 429. This standard shall not be interpreted to require the immersion test unless specified by the purchaser.
2.3.5 The entire stator winding insulation system. including winding connections and terminal leads, shall be lightly secured to prevent insulation cracking and fatigue as a result of rw)tion and vibrations during starting. operation and electrical transielu conditions which produce electromechanical fi.rces in the stator windings. The windings shall withstand electromagnetic and mechanical forces under normal operating conditions. the starting requirements specified in 2.2.2.3 and 2.2.2.6 and the krces associated with phase-to-phase and 3-phase short-cireuits with 110% of rated voltage.
2.3.6 The insulation system. including leads, shall be compatible with mineral oil based lubricants. Type test andor design intinnation shall be supplied when requested on identical lead insulating material to verify this requirement has been satisfied.
2.4 MECHANICAL DESIGN
2.4.1 Enclosures
2.4.1.1 General Requirements
Enclosure parts shall be made of cast or nodular iron, caM steel, or steel plate. All enclosure parts shall have a minimum rigidity equivalent to that of sheet steel with a nominal thickness of l, in. (3.0 mm). Designs in which the stator laminations form a part of the external enclosure are not acceptable. The motor shall be Totally-enclosed Fan-cooled tTEFC) (1P44-54/lC4l I) or Weather-protected Type II (WP II) (1P24W.ICOI)as defined below.
2.4.1.2 Totally-enclosed Fan-cooled motors (TF..FC) shall meet the following criteria:
a. The slator frame shall be of east iron construction.
b. Fan covers shall be made of metal having a minimum rigidity equivalent to that of steel plate with a nominal thickness of in. (3.0 mm). Purchaser-approved fiberreinforced materials may be used. The air intake opening shall be guarded by a grill or a metal screen. Protective grills or metal screens shall be fabricated from not lessthan 0.049 in. (1.25 mm) AISI (American lron and SteelInstitute) 300 series stainless steel with a maximum meshof 1/4 in.(6.4 mm). Where the motor will be installed off-shore AIS1 316 material shall be supplied.
c. Sheet metal covers or wrappers used to form air pas-sages over the enclosure shall have a minimum rigidityequivalent to that of steel plate with a nominal thickness of l/s in.(3.0 mm).
d. Corrosion-resistant, replaccable automatic drainage fit-tings shall be provided within 5 degrees of the lowest point ofthe motor enclosure (when viewing the end of the frame froman axial direction).This connection shall be shown on theoutline drawing.
2.4.1.3Weather-protected Type (WP II) enclosures, shallmeet the following criteria.