IEEE 117-2015 pdf download
IEEE 117-2015 pdf download.IEEE Standard Test Procedure for Thermal Evaluation of Systems of Insulating Materials for Random-Wound AC Electric Machinery.
5. Motorettes
5.1 Insulation test specimens
5.1.1 Motorette general construction
This subcbuse suggests appropriate test specimens for evaluating insulating systems that may be usefully subjccted to the exposures outlined in 5.2. to simulate their bchavior in service. It is considered that one type of mocorette, as defined in the following, will adequately represent random-wound machines of both fractional and integral horsepower of 600-V rating or less. Other types of specimens will be required to represent machines with operating voltages other than tsO() V and with other than random-wound insulation systems. Procedures for evaluating such other types of insulation fall outside the scope ofthis standard. (See IEEE Std 1l07.1996[Bl5] and IEEE Std 1176[Bl6J.)
5.1.2 Motorettes
The model shall be made to embody all of the elements and should be. as nearly as possible, representative of a complete winding insulation system, Specifically, it is recommended that for the purposes of testing random-woutid motor insulation a motorelte be employed, as showit in Figure I, Figuic 2. and Figurc At least 10 motorettes shall be subjected to each of a series of test exposures outlined in 5.2.
Figure I shows typical components of a motorette before final assembly, while Figure 2 shows the assembled moorcttc. and Figure 3 shows the motorette frame dimensions. Each of these components should be subjected to separate screening tests to establish uniformity and normality before they are assembled, For example. a number of representative samples of the wire, slot, and phase insulation, as well as wedges, all of which may be broken down by ac high-potential tests or other means. It should be recognized that the number of tests that are required to establish the acceptable temperature limit in service will increase greatly, if the perft’irmanceof individual components varies over a wide r.mge. Therefore, everything possible should be done to assure that the individual components arc uniform and representative of the matenals used in actual service.
Thc finished motorette consists of a rigid supporting metal stand with four suitable stand-ofT porcelain insulators bolted to one end and with a slot portion. made from an inner and outer plate, bolted to the other end. The supporting stand has holes for mounting the fixture during vibration testing. The slot sections are fabricated from US Standard #16 gauge (1.52 nim (0.060 ml) steel sheets such as AISI 1010 cold rolled steel. The assembled slot portion contains two coils of magnet wire insulated from ground by slot insulation, insulated from each other by phase insulation, and held in place with slot wedges. These components are typical parts used in actual motors. The coils are each wound with two parallel wires ibifilar wound) so that conductor-to-conductorclecmcal tests may be made. They can be machine wound on pins or forms, as in ordinary shop practice.
In special cases, the construction and processing procedures may be modified to simulate the intended use.
5.1.3 Preparation of motorettes
5.1.3.1 OvervIew of preparation
The following is a detailed description of the preparation of the motorette test samples for this standard test method. ibis motorette description is based on historic industry-wide testing. As noted in the last sentence of 5.1.2. modifications may be made to more clearly simulate the intended use, provided the control and candidate test specimens are modified in the same manner, The methodology for testing of multiple materials on one motorette specimen has not been standardited and has not been established as part of this standard.
5.1.3.2 Components used in motorette constructIon Thc components used in motorette construction arc as follows:
5.1.3.3 Motorette assembly
The motorette assembly shall he as follows:
a) Hetiwe assembly, each metal component of the moorette is immersed in a solvent composed of equal parts of toluene and denatured alcohol for at least 30 ml. Each part is removed fmm the solent. rinsed with fresh solvent, and wiped with a lint-free cloth. The motorettc metal pans are carefully assenibled. ensuring that the slot portions are equal in width and sides parallel. A simple de ice for this is to cut two wooden blocks equal in width lo the slot portion and center the slot by placing the blocks in the slot portion prior to tightening slot hold down bolts.
