IEEE 841-2009 pdf free download – IEEE Standard for Petroleum and Chemical Industry—Premium- Efficiency, Severe-Duty, Totally Enclosed Fan-Cooled (TEFC) Squirrel Cage Induction Motors—Up to and Including 370 kW (500 hp)
3. Service conditions
3.1 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
b) Exposure to a maximum altitude of 1000 m 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 1 Division 2 and Class 1 Zone 2 areas on sine wave power in accordance with the applicable codes and standards
3.2 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
1) Flammable or explosive gases
2) Combustible, explosive, abrasive, or conductive dust
3) Lint or dirty operating conditions where the accumulation of dirt will interfere with normal ventilation
4) Nuclear radiation
5) Abnormal shock, vibrations, or mechanical loading from external sources
6) Abnormal axial or side thrust imposed on the motor shaft
7) Altitude or ambient temperature outside the range covered in 3.1
b) Conditions under which the variation from rated voltage or frequency, or both, differ from the limits given in item a) of 5.3.1
c) Conditions under which the ac supply voltage is unbalanced by more than 1% (see Section 14.36 of NEMA MG 1-2006 9 )
d) Operation at speeds other than rated speed
e) Operation from solid-state or other types of adjustable frequency or adjustable voltage power supplies for adjustable speed applications
f) Load inertia greater than and/or starting conditions more severe than specified in Section 12.54 of NEMA MG 1-2006
g) Exposure to conditions where IP 55 protection is not sufficient
NOTE—The use of high-efficiency (low-slip) motors for reciprocating loads or special torque loads such as hoists should also be reviewed with the manufacturer. 10
4. Ratings
4.1 Basis of rating
Motors shall be rated on a continuous-duty basis. 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 a 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.
4.2 Frame assignments
To the extent applicable, motors shall comply with the frame size assignments of NEMA MG 1-2006,Part 13.
4.3 Voltage and frequency ratings
The standard voltage ratings for 60 Hz 3 phase are 200 V, 230 V, 460 V, 575 V, 2300 V, and 4000 V. Dual voltage motors are acceptable only for 2300 V and 4000 V ratings. Voltage ratings for 50 Hz 3 phase are 230 V, 400 V, 690 V, and 3300 V.
NOTE—It is not practical to build induction motors of all ratings at all of these voltages.
4.4 Synchronous speed ratings
Synchronous speed ratings at 60 Hz are 3600 r/min, 1800 r/min, 1200 r/min, or 900 r/min.
Synchronous speed ratings at 50 Hz are 3000 r/min, 1500 r/min, 1000 r/min or 750 r/min.IEEE 841 pdf download.