IEEE Std 841 pdf free download

IEEE Std 841 pdf free download.Petroleum and Chemical Industry- Premium-Efficiency, Severe-Duty, Totally Enclosed Squirrel Cage Induction Motors from 0.75kWto370kW(1 hp to500hp).
5.2 Frame assignments
To the extent applicable, motors shall comply with the frame size assignments ofNEMA MG 1-20 16, Part 13.
5.3 Voltage and frequency ratings
The standard voltage ratings for 60 Hz three phase are 200 V, 230 V. 460 V, 575 V. 2300 V. and 4000 V. Voltage ratings for 50 Hz 3 phase are 220 V and 380 V. When specified, a non-standard voltage shall be permitted.
5.4 Synchronous speed ratings
Synchronous speed ratings at 60 Hz are 3600 r/rnin, 1800 r/min, 1200 r/min, or 900 r/min.
Synchronous speed ratings at 50 Hz are 3000 r!rnin, 1500 r/min, 1000 r/min, or 750 r/min.
5.5 Enclosures
Enclosures shall be totally enclosed fan cooled (TEFC) or totally enclosed non-ventilated (TENV) and shall have a minimum degree of protection of IP 55. If replaceable shaft seals are used to achieve this degree of protections, they shall be the noncontact or noncontacting-while-rotating type with a minimum expected seal life of five years under usual service conditions. Degrees of protection are defined in NEMA MG 1-20 16, Part 5. Drain fitting holes are permitted to be plugged during the enclosure ingress test.
6. Electrical performance
6.1 General
Unless othenvise specified in this standard, motor electrical performance and characteristics shall be in
accordance with NEMA MG 1.
6.2 Motor designs and starting characteristics
Motors shall have Design B torque/current characteristics and starting capability as defined in NEMA MG 1-2016, Part 12. Where power and speed ratings fall outside Part 12, characteristics and capabilities shall meet or exceed the specifications defined in NEMA MG 1-2016. Part 20.
All motors shall meet NEMA MG 1-2016, Part 30 and clause 31.4.4.2 of NEMA MG 1-2016, Part 31.
6.3 Power supply variations
6.3.1 Sine wave supply voltage
a) The motor’s power supply shall be as follows: Motors shall operate successfully under running conditions at rated load with variation in the voltage or frequency not exceeding the following conditions (from NEMA MG 1):
1) ± 10% of rated voltage, with rated frequency
2) ± 5% of rated frequency, with rated voltage
b) Combination of voltage and frequency variation of 10% (sum of absolute values) of the rated values, provided that the frequency variation does not exceed ±5% of rated frequency
NOTE—For the effects of voltage, voltage unbalance, and frequency on motor performance. see clause 14.30 through 14.36 of NEMA MG 1-2016.
6.3.2 Adjustable speed drive (ASD) supply
Pulse width modulated (PWM) ASD carrier frequency shall be 2 kHz or higher. Refer to Annex B for ASD application considerations.
NEMA has recognized the elevated stresses imposed on induction motors by adjustable frequency controls and has developed a performance standard for motors that are specifically identified as “inverter duty” or “inverter rated”. Motors used in ASDs shall meet NEMA MG 1-20 16, Part 30 and clause 3 1.4.4.2 of NEMA M(I 1-2016, Part3l.
6.3.2.1 ASD application parameters
The motors utilized with an ASD shall be applied and designed as follows:
a) The operating load shall not exceed the base nameplate rating of the motor.
b) The motor shall be operated at or below nameplate speed.
c) The shaft load profile shall be variable torque, such as centrifugal fan, centrifugal pump, or centrifugal compressor, where the torque varies approximately as the square of the speed.
d) The maximum exposed motor surface temperature shall not exceed 200 °C (392 °F) at any design load condition when operated on the ASD.
NOTE—An cxposed surface” for totally enclosed motors includes the internal stator and rotor surfaces.
e) The motor shall have ASD nameplate information in accordance with Item f) in 11 .1.
NOTE——These Common ASD parameters have been shown by expcricnce not to he a source of ignition. However, motor manufacturers and uscrs should discuss cach application to determine the conditions described in 6.3.2.1 are satisfied and engineering judgment should be used when applying motors in a hazardous (classified) location.
IEEE Std 841 pdf download.