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MI-M-17413A( NAVY)
3.6.1.2.1 Where the resistance of the winding iS 1.0 ohm or more, method 2 (resistance) applies.
Where the resistance of the winding is less than 1 ohm, the temperature measurements shall be deter-
mined by method 1 (themometer) except for those motors where the windings are inaccessible, in which
case method 2 (resistance) shall be used.
3.6.1.3 Shock resistance. - The motors shall be capable of withstanding the high-impact shock test
specified in Specification MIL-S-901 and 4.2.4.22 herein.
3.6.1.4 Armature windings. - In motors of a frame size larger than that used for a motor having a
rating of 5 horsepower at 1150 r. p. m. the armature coils shall be form-wound (that is, wound, formed,
and Insulated before assembly in the core slots) and interchangeable. The coils shall be securely retained
in the slot by wedges. Banding wire shall not be used to secure the windings in the slot. Where steel
banding wire is used to band the armature end turn windings, the wire shall be in accordance with Specific-
ation MIL-W-806 or MIL-W-3068. The insulation used Uncle r the wire shall be type FP, FC or RP of
Specification MIL-I-695 for class A and pasted mica in accordance with Specification HH-I - 538 or mica-
glass combination in accordance with Specification MIL-I-3505 for class B or H.
3.6.1.5 Brush holder springs. - Brush holder springs shall be in accordance with Specifica-
tion MIL-H-17678. The spring shall not be depended upon to carry current.
The type of brush holders shall be as follows:
3.6.1.6 Brush holders. -
(a) For reversible motors: Box type only.
(b) For nonreversible motors: Box or type open.
3.6.1.7 Radio noise. - The design of the motors shall be such as to minimize the generation of
radio interference. Where suppression harnesses are required to reduce radio noise to the limits speci -
fied (see 6.2) impedance coils and capacitors designed for suppression purposes shall be satisfactory to
the bureau or agency concerned, and shall be capable of withstanding high impact shock test in accordance
with Specification MIL-S-901. Capacitors shall be in accordance with Specification MI L-C -25.
3.6.1.7.1 Radio interference suppression devices, where required, shall be readily removable for
replacement purposes and shall be capable of withstanding a voltage of 600 volts. If necessary the radio
interference suppression devices may be removed from the circuit when the motor in being subjected to
the dielectric test specified in 4.2.4.12.
3.6.1.7.2 When specifically required (see 6. 2), the motors covered by this specification shall comply
with Specification MIL-I-16910, including suppression limits, under all load and speed conditions.
3.6.1.8 Change in speed due to heating. -  Motors shall be so designed that the change in motor
speed from rated load cold to rated load hot, based on rated load speed hot shall not exceed the following
percentages:
Class A insulation
Open - 10 percent
Others - 15 percent
Classes B and H insulation
All degrees of enclosure - 15 percent
20

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