2.2 Other publications. The following document forms a part of this specification. Unless other-
wise indicated, the issue effect on date of invitation for bids shall apply.
224.7- Apparatus Noise Measurements.
(Application for copies should be addressed to American standards Association, 70 East 45th Street,
New York 17, New York. )
3.1 Definitions. - The following definitions shall apply to the various technical terms wherever
such terms appear in this specification:
3.1.1 Continuous duty. - Continuous duty is a requirement of service that demands operation at a
substantially constant load for an indefinitely long time (see 3.2.6. 1).
3.1.2 Intermittent duty. - Intermittent duty is a requirement of service that demands operation for
alternate intervals of (a) load and no-load, or (b) load and rest, or (c) load, no-load, and rest
3.1.3 Varying duty - Varying duty is a requirement of service that demands operation at loads
and for intervals of time, both of which may be subject to wide variation (see 126.96.36.199).
3.1.4 Short-time duty. - Short-time duty is a requirement of service that demands operation at a
substantially constant load f or a short and definitely specified time (see 188.8.131.52).
3.1.5 Contact-speed motor. - A constant-speed motor is one of which the normal speed of operation
is constant or practically constant; for example, a shunt-wound motor.
3.1.6 Multispeed motor. - A multispeed motor is one which can be operated at any one of two or
more definite speeds, each being practically independent of the load.
3.1.7 Adjustable-speed motor. - An adjustable-speed motor is one the speed of which can be varied
gradually over a considerable range, but when once adjusted remains practically unaffected by the load.
3.1.8 Base speed of adjustable-speed motor. - The base speed of an adjustable-speed motor is the
lowest speed obtained at rated load and rated voltage at normal operating temperatures.
3. 1.9 Varying-speed motor. - A varying-speed motor is one the speed of which varies in consider-
able degree with change in load, ordinarily decreasing when the load increases, such as a series motor.
3.1.10 Adjustable varying-speed motor. - An adjustable varying-speed motor is one the speed of
which can be adjusted gradually, but when once adjusted for a given load, will vary in considerable degree
with change in load.
3.1.11 Front (of motor). - The front of a motor is the end opposite the coupling. For a motor having
a coupling on each end, it is the end with the commutator.
3.1.12 Back (of motor). - The back of a motor is the end which carries the coupling or driving pulley.
For a motor having a coupling on each end, it is the end opposite the commutator.
3.1.13 Shunt-wound motor. - A shunt-wound motor is a direct current motor in which the field circuit
and armature circuit are connected in parallel. If a light series winding is added to prevent a rise in
speed with increase of load, the motor is termed stabilized shunt-wound.
3.1.14 Series-wound motor. - A series-wound motor is one in which the field circuit and armature
circuit are connected in series.