IEEE 841-2021 pdf download

IEEE 841-2021 pdf download.IEEE Standard for Petroleum and Chemical Industry— Premium-Efciency, evere-Duty, Totally Enclosed Squirrel Cage Induction Motors from 0.75 kW to 370 kW (1 hp to 500 hp)
3. Defnitions, acronyms, and abbreviations
3.1 Defnitions
For the purposes of this document, the following terms and definitions apply. The IEEE Standards Dictionary Online should be consulted for terms not defined in this clause.
adjustable speed drive (ASD): An interconnected combination of equipment that provides a means of adjusting the speed of a mechanical load coupled to a motor. A drive system consists of a drive and auxiliary electrical apparatus.
NEMA frame: This refers to the NEMA MG 1 system of a standardized frame designation for ac machines including 449 frame size and smaller. NEMA MG 1-2016, Part 4 provides critical mounting dimensions for each frame size.
service factor, ac motors: The service factor of an ac motor is a multiplier which, when applied to the rated
horsepower, indicates a permissible horsepower loading which may be carried under the conditions specifed for the service factor (i.e., usual service conditions). Note the performance will change as defned in 14.37 of NEMA MG 1-2016 when operating at any service factor above 1.0.
3.2 Acronyms and abbreviations
ASD adjustable speed drive
AIT auto ignition temperature
CMV common-mode voltage
FLA full load amps [See: full load current (FLC)]
FLC full load current [See also: full load amps (FLA)]
IP 55 Ingress Protection Level 55 (Dust-protected machine/Machine protected against water jets)
PWM pulse width modulated
TEAO totally enclosed air over
TEFC totally enclosed fan cooled (IC411)
TENV totally enclosed non-ventilated (IC410)
4. Service conditions
4.1 Usual service conditions
Unless otherwise specified, motors conforming to this standard shall be suitable for operation within their rating under the following service conditions:
a) Exposure to an ambient temperature in the range of –25 °C to +40 °C (–13 °F to +104 °F)
b) Exposure to a maximum altitude of 1000 m (3300 ft) above sea level
c) Indoor or outdoor severe-duty applications, such as humid, chemical (corrosive), or salty atmospheres
d) Full voltage across-the-line starting
e) Application in Class I, Division 2, and Zone 2 areas on sine wave or inverter power (ASD) in accordance with the applicable codes and standards
f) Variable torque operation from solid-state, PWM ASD for motors 1000 V or less. See 6.3.2 for ASD information
g) Power supply variations as stated in 6.3.1.
4.2 Unusual service conditions
Unusual service conditions should be brought to the attention of those responsible for the design, manufacture,application, and operation of the motor. Such unusual conditions include the following:
a) Exposure to the following:
1) Lint or dirty operating conditions where the accumulation of dirt will interfere with normal ventilation
2) Nuclear radiation
3) Abnormal shock, vibrations, or mechanical loading from external sources
4) Abnormal axial or side thrust imposed on the motor shaft
5) Altitude or ambient temperature outside the range covered in 4.1
b) Conditions under which the variation from rated voltage or frequency, or both, differ from the limits given in item a) of 6.3.1
c) Conditions under which the ac supply voltage is unbalanced by more than 1% (see Part 14 of NEMA MG 1-2016 13 )
d) Operation at speeds above synchronous speed
e) ASD operation as constant torque or constant horsepower operation
f) ASD operation at voltage above 1000 V
g) Load inertia greater than and/or starting conditions more severe than specifed in Part 12 of NEMA MG 1-2016 when applied to rated frequency sinewave power.
h) Exposure to conditions where Ingress Protection Level 55 (IP 55) protection is not suffcient
5. Ratings
5.1 Basis of rating
Motors shall be rated on a continuous-duty basis at rated power (1.0 service factor). Motor nameplates may reflect capability above 1.0 service factor. The output rating shall be expressed in power available at the shaft at the specified speed, frequency, and voltage.
NOTE—Motors should be applied within their rating based on a service factor of 1.0. In applications requiring   prolonged overload capacity, the use of a higher power rating is recommended to avoid the reduction of insulation and bearing life associated with operation above the 1.0 service factor.IEEE 841 pdf download.IEEE 841-2021 pdf download