NE 47 has been revised

from 2019-12-16

The NAMUR Recommendation NE 47 has been revised in a joint working group of NAMUR and VIK and may now be obtained as NAMUR Recommendation from the NAMUR Office.

Compared to NE 47 edition 2011-05-04 there were changes in the following topics:

  • Ex-marking
  • Voltage area
  • Corrosion prevention
  • Entry of the power supply cables
  • Energy efficiency - IE3
  • Insulation strength
  • Noise emission – tonality
  • tE-time
  • Motor protection with PTC thermistors

Abstract NE 47 ‘3-Phase Asynchronous Motors; Technical Requirements’
(Edition: 2019-12-16)

In many cases, commercially available 3-phase asynchronous motors for low-voltage application do not satisfy the requirements of the market, even when they are conceived as robust, low-maintenance items. Special conditions of use – as are met for example, in the raw materials industry, in power plant equipment and in refineries – and the increasing significance of the availability and quality of these motors, due to the pressure of competition in the ever globally expanding markets, make additional demands on their design and construction.

In order to enable rational procedures to be adopted for ordering, stock keeping and operational use, it is necessary, moreover – in the opinion of the specialists concerned, who are all from VIK/NAMUR member companies – to standardize the design of the motors as far as possible. To this end, the requirements of users regarding low-voltage asynchronous motors, for the listed conditions of use, have already been summarized in 1975, in a VIK recommendation ‘3-Phase Asynchronous Motors; Technical Requirements’.

This current, updated issue of the VIK-recommendation has been adapted and expanded by the VIK/NAMUR ‘Drive Technology’ Committee, to satisfy the state of the art, the standards and the current experiences of the industrial users within the circle of VIK/NAMUR members. It is directed, in particular, to those responsible for electrical engineering in trade and industry and is intended as an aid to finding optimal technical and economic solutions.

In the actualized edition, the topics ex-marking, voltage area, corrosion prevention, power supply line, energy efficiency, insulation strength, noise emission and tE time have been updated. The new topic motor protection with PTC thermistor has been added.

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