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Permissible variation from rated speed |
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|  MIL-M-17413A(NAVY)
3.6.1.23 Cable connectors. - For motors having frame sizes corresponding to 7-1/2 horsepower
at 1800 r.p.m and larger, this connector shall be of the solderless type Conforming to Specifica-
tion MIL-E-16366, (see 3.2.24.4).
3.6.1.24 Permissible variation from rated speed. - The variation of the actual motor speed at
rated voltage and load from rated speed shall not exceed the tolerances required for satisfactory operation
of the driven auxiliary. Unless closer tolerances are required for satisfactory operation of the driven
auxiliary, the variation of the actual speed at rated loads rated voltage, at normal operating ternperature,
and for both directions of rotation from rated full-load speed shall not exceed the following:
Constant-speed motors
Seven and one-half percent for motors UP to and including 7-1/2 horsepower at 1,150 r. p. m.
Five percent for motors larger than 7-1/2 horsepower at 1,150 r. p. m.
Adjustable-speed motors
Seven and one-half percent for motors having a rating up to and including 5 horsepower
at 650 r.p.m.
Five percent for motors larger than 5 horsepower at 650 r. p. m.
3.6.1.25 Speed regulation. -
3.6.1.25.1 Motor speed regulation shall be positive, that is, it shall decrease to at least a slight
extent with increase of load. Motors having a full-load or overload speed greater than the no-load speed,
at corresponding temperatures, will not be accepted.
3.6.1 .25.2 The speed regulation of constant-speed, continuous-duty motors at normal operating tern -
peratures, shall not exceed the following:
(a) For motors up to and including 5 horsepower at 850 revolutions per minute,
12 percent.
(b) For motors larger than 5 horsepower at 850 revolutions per minute, 10 percent.
3.6.1.25.3 The speed regulation of adjustable-speed motors at normal operating temperatures, shall
not exceed the following:
(a) For motors having a speed range of 4:1, at full-speed rating, 18 percent.
(b) For motors having a speed range of less than 4:1, and for ratings of
3 horsepower and below, at full-speed rating, 18 percent.
(c) For motors having a speed range of less than 4:1, and for ratings above
3 horsepower, at full speed rating, 15 percent.
3.6. 1.25.4 The speed regulation of varying-speed motors shall not exceed the amount specified
(see 6. 2).
3.6. 1.25.5 Where the safe satisfactory operation of the driven auxiliary requires a speed regulation
w h i c h is closer than the value specified in 3.6.1.25.2, 3.6.1.25.4, the needs of the driven
auxiliary shall determine the permissible speed regulations in the particular cases.
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