IEC 61986-2002 pdf – Rotating electrical machines – Equivalent loading and super-position techniques – Indirect testing to determine temperature rise.
1 Scope This International Standard applies to machines covered by IEC 60034-1 when they cannot be loaded to a specific condition (rated or otherwise) for whatever reason. It is applicable to both motors and generators but the methods are not suitable for machines of and below 1 kW. The object of this standard is to provide descriptions of various indirect load tests, the purpose of which is to determine the temperature rise of rotating electrical machines, including a.c. induction machines, a.c. synchronous machines and d.c. machines. The test methods in some cases provide, in addition, a means of measuring or estimating other parameters such as losses and vibration, but the methods are not designed specifically to provide such data. The proposed methods of test are considered equivalent, the choice of them relying only on the location, the testing apparatus and the kind of machine, and the test result accuracy. It is not intended that this standard be interpreted as requiring the carrying out of any or all of the tests described therein on any given machine. The particular tests to be carried out are subject to a special agreement between the manufacturer and the purchaser. As the methods reproduce only approximately the thermal conditions of the machines which occur under normal rated condition, temperature-rise measurement results achieved from tests with these methods can be taken as the basis for the evaluation of machine heating according to 7.10 of IEC 60034-1 by agreement between the manufacturer and the purchaser.
2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amend- ments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of IEC and ISO maintain registers of currently valid International Standards. IEC 60034-1, Rotating electrical machines – Part 1: Rating and performance IEC 60034-2, Rotating electrical machines – Part 2: Methods for determining losses and efficiency of rotating electrical machinery from tests (excluding machines for traction vehicles)
4 General test requirements Measurement of the electrical parameters shall be made as follows. a) The class of accuracy of measuring instruments shall be not greater than 0,2, with the exception of wattmeters with cos ϕ lower than 0,5 and frequency meters, which may have accuracy class 0,5. b) The measuring range of the instruments shall be chosen with a view to the measured values being higher than 30 % of the full-scale range. These requirements need not be complied with in the case of the three-phase power measurement by means of two wattmeters, but the currents and voltages in the measured circuits shall be at least 20 % of the rated currents and voltages of the wattmeters being used. The range of the other measuring instruments shall be chosen in such a way that the measuring errors are not increased. c) The waveform and dissymmetry of the supply voltage at the machine terminals shall be in accordance with the requirements of 6.1 to 6.5 of IEC 60034-1. d) Each line current shall be measured. If these are unequal, the arithmetic average value shall be used to determine the machine operating point. e) Power input to a three-phase machine may be measured by two single-phase wattmeters connected as in the two-wattmeter method, or one polyphase wattmeter, or three single- phase wattmeters. The total power read on a wattmeter shall be reduced by the amount of the I 2 R loss in the voltage circuits or in the current circuits of the instruments according to their connection whenever this loss is a measurable portion of the total power. There is no need to reduce the total power read on a wattmeter by the amount of the I 2 R losses for digital measuring instruments. All the electrical quantities to be measured are root-mean-square values unless otherwise indicated.