1. SCOPE

1.1 This standard covers the efficiency classes and performance specifications of single-speed line operated a.c. motors that are rated according to IS 15999 (Part 1)/IEC 60034-1, rated for operation on a sinusoidal voltage supply and :

a) Have a rated power from 0.12 kW to 1 000 kW;

b) Have 2, 4, 6 or 8 poles;

c) Have a rated voltage Un up to 1 000 V with a rated frequency of 50 Hz;

d) Frame size from 56 up to and including 315 M having Frame to output co-relation as specified in Table 3 of IS 1231;

e) Frame size 315 L with dimensions as per IS 1231 and having output rating as declared by motor manufacturer;

f) Frame size 355 and above, with dimensions and output ratings as declared by motor manufacturer but conforming to IS 8223;

g) Are capable of continuous operation at their rated power with a winding temperature rise within the specified insulation temperature class;

h) Are marked with any ambient temperature within the range of – 20°C to + 60°C;

j) Are marked with an altitude up to 4 000 m above sea level;

k) This standard covers motors with or without service factor;

m) Most motors covered by this standard are primarily rated for duty type S1 (continuous duty). Motors rated for duty cycles S2 and above with an equivalent S1 duty are also covered. These motors must also be marked with the equivalent S1 duty output and its corresponding IE class. Declaration of S1 duty output value may be as per mutual agreement between motor manufacturer and customer. (see 12)

n) Motors with output power rating higher than as specified in Table 3 of IS 1231 for a given frame, must meet the efficiency class corresponding to that power rating.

NOTES

1 The rated efficiency and efficiency classes are based on 25°C ambient temperature according to IS 15999 (Part 2/Sec 1) : 2011 and winding temperature rise of motor at rated power output.

2 Motors rated for temperatures outside the range – 20°C and + 60°C are considered to be of special construction and are consequently excluded from this standard.

3 Smoke extraction motors with a temperature class of up to and including 400°C are covered by this standard.

4 The rated efficiency and efficiency class are based on a rating for altitudes up to 1 000 m above sea level.

5 Motors with service factor greater than 1.0 must have efficiency corresponding to the rated power. Service factor greater than 1.0 is intended for short time (< less than 1 h) use only.

1.2 This standard establishes a set of efficiency values based on frequency, number of poles and motor output power. No distinction is made between motor technologies, supply voltage or motors with increased insulation designed specifically for converter operation even though these motor technologies may not all be capable of reaching the higher efficiency classes (see Table 1 to Table 4). This makes different motor technologies fully comparable with respect to their energy efficiency potential.

1.3 Motors with customized dimensions different from IS 1231 are also covered by this standard. (see 7 also) Geared motors are covered by this standard including those incorporating non-standard shafts and flanges.

Totally enclosed air-over (TEAO IC418) machines, that is totally enclosed frame-surface cooled machines intended for exterior cooling by a ventilating method external to the machine are covered by this standard. Efficiency testing of such motors may be performed with the fan removed and the cooling provided by an external blower with a similar airflow rate as the original fan.

Methods of cooling shall be IC411, IC511 or IC611. (see 6 also)

Sometimes motors are required to be offered in frame sizes higher than as stipulated in Table 3 of IS 1231. Such cases are covered for IE classification and marking. The motor shall meet the performance parameters of the rated power (Table 1 to Table 4).

1.4 This standard does not cover the following motors:

a) Single-speed motors with 10 or more poles or multi-speed motors;

b) Motors with mechanical commutators (such as Universal – a.c./d.c. motors);

c) Slip ring induction motors;

d) Screen protected drip proof motors with IP21, IP22 and IP23 protection.

e) Motors completely integrated into a machine (for example mono-block pump. fan and compressor) that cannot be practically tested separately from the machine even with provision of a temporary end-shield and drive-end bearing. This means the motor shall:

1) Share common components (apart from connectors such as bolts) with the driven unit (for example. a shaft or housing) and;

2) Not be designed in such a way as to enable the motor to be separated from the driven unit as an entire motor that can operate independently of the driven unit. That is for a motor to be excluded from this standard the process of separation shall render the motor inoperative;

f) Motors with integrated frequency-converters (compact drives) when the motor cannot be tested separately from the converter. Energy efficiency classification of compact drives shall be based on the complete product (PDS: Power Drive System) and will be defined in a separate standard;

NOTE - A motor is not excluded when the motor and frequency-converter can be separated and the motor can be tested independently of the converter.

g) Brake motors when the brake is an integral part of the inner motor construction and can neither be removed nor supplied by a separate power source during the testing of motor efficiency;

NOTE - Brake motors with a brake coil that is integrated into the flange of the motor are covered as long as it is possible to test motor efficiency without the losses of the brake (for example by dismantling the brake or by energizing the brake coil from a separate power source).

When the manufacturer offers a motor of the same design with and without a brake the test of motor efficiency may be done on a motor without the brake. The determined efficiency may then be used as the rating of both motor and brake motor.

h) Submersible motors specifically designed to operate wholly immersed in a liquid; and

j) Smoke extraction motors with a temperature class above 400°C.

1.5 The efficiency of power-drive systems is not covered by this standard. In particular, motor losses due to harmonic content of the supply voltage, losses in cables, filters and frequency converters, are not covered.

1.6 To conform to this standard and eligible to be marked with an IE stamp, the motors shall meet the norms specified in Table 1 to Table 4 when read in conjunction with Clause 4 related to site conditions as applicable. All performance values are subjected to tolerances specified in IS 15999 (Part 1)/IEC 60034-1.

2. REFERENCES

The standards given below contain provisions which, through reference in this text, constitute provisions of this standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of these standards.

IS 1231 : 1974 Dimensions of three phase foot mounted induction motors

IS 1885 (Part 35) : 1993 Electrotechnical vocabulary: Part 35 Rotating machines

IS 2223 : 1983 Dimensions of flange mounted a.c. induction machines

IS 2254 : 1985 Dimensions of vertical shaft motors for pumps

IS 3043 : 1987 Code of practice for earthing

IS 7816 : 1975 Guide for testing insulation resistance of rotating machines

IS 8223 : 1999 Dimensions and output series for rotating electrical machines

IS 900 : 1992 Code of practice for installation and maintenance of induction motors

IS 12065 : 1987 Permissible limits of noise level for rotating electrical machines

IS 12075 : 2008 mechanical vibration of rotating electrical machines with shaft heights 56 mm and higher — measurement, evaluation and limits of vibration severity

IS 15999 (Part 1) : 2016 Rotating electrical machines: Part 1 Rating and performance

IS 15999 (Part 2/ Sec 1) : 2011 Rotating electrical machines: Part 2 Method of tests, Section 1 Standard methods for determining losses and efficiency from tests (excluding machines for traction vehicles)