EN IEC 60034-2-3 pdf download.ROTATING ELECTRICAL MACHINES – Part 2-3: Specific test methods for determining losses and efficiency of converter-fed AC motors
1 Scope
This part of IEC 60034 specifies test methods and an interpolation procedure for determining losses and efficiencies of converter-fed motors within the scope of IEC 60034-1 :201 7. The motor is then part of a variable frequency power drive system (PDS) as defined in IEC 61 800-9-2:201 7. Applying the approach of the comparable converter, the motor efficiency determined by use of this document is applicable for comparison of different motor designs only. The document also specifies procedures to determine motor losses at any load point (torque, speed) within the base speed range (constant torque range, constant flux range) based on determination of losses at seven standardized load points. This procedure is applicable to any variable speed AC motor (induction and synchronous) rated according to IEC 60034-1 :201 7 for operation on a variable frequency and variable voltage power supply.
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60034-1 :201 7, IEC 60034-2-1 :201 4 as well as the following apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: • IEC Electropedia: available at http://www.electropedia.org/ • ISO Online browsing platform: available at http://www.iso.org/obp 3.1 motor losses with converter supply when powered by a converter, motor losses are a combination of losses caused by fundamental frequency and losses caused by the converter high frequencies 3.2 fundamental losses fundamental losses in the motor can be segregated into five different components: iron losses (varying with motor frequency and applied fundamental voltage), friction and windage losses (varying with motor speed), rotor winding losses, stator winding losses and additional load losses (all three varying with motor current). Fundamental losses are the losses of a motor running with application of rated voltage at fundamental frequency that does not contain any further high frequencies. 3.3 additional high frequency losses additional high frequency losses are produced in the motor by the non-sinusoidal voltage and current waveforms generated by the converter and are in addition to the losses of iron, friction and windage, rotor winding, stator winding and additional load loss (fundamental losses) 3.4 base speed range speed range from standstill up to the highest speed where the motor can be supplied with a voltage that changes in proportion to the speed so that the magnetic flux remains constant (constant ratio U/f) for induction machines and according to the MTPA (maximum torque per ampere) for synchronous machines. Within the base speed range, the maximum motor torque is constant (constant torque range), if constant flux control is used.3.5 switching frequency number of switching events of one semiconductor within one second. It determines, together with the selected pulse pattern and the converter topology, the lowest frequency of non- controllable high frequencies or inter-harmonics at the IPC (in-plant point of coupling) or the motor Note 1 to entry: For a two level converter, the pulse frequency measured phase to phase is two times the switching frequency defined in 3.5 in case of continuous modulation and about 1 ,33 times the switching frequency defined in 3.5 in case of discontinuous modulation. A switching event is once on and once off of one semiconductor.
5 Basic requirements
5.1 Instrumentation 5.1.1 General Unless otherwise stated in this document, the arithmetic average of the three line currents and voltages shall be used. When testing electric machines under load, slow fluctuations in the output power and other measured quantities may be unavoidable. Therefore for each load point many readings shall be taken automatically by a suitable digital meter over a period of at least 1 5 s but not more than 60 s and this average shall be used for the determination of efficiency. Considering the high frequencies involved in converters feeding AC motors and their contribution to the motor losses, the measuring equipment has to be selected according to the range of relevant frequencies with sufficient accuracy. For temperature measurements, a thermosensor installed in the hot spot may be optionally used, as described in IEC 60034-2-1 :201 4.
EN IEC 60034-2-3 pdf download
