crimping test

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Purdue University

Purdue e-Pubs

International Compressor Engineering Conference School of Mechanical Engineering

1974

Crimp Type Winding Connections in HermeticMotors

G. W. KleinGeneral Electric Company

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Klein, G. W., "Crimp Type Winding Connections in Hermetic Motors" (1974). International Compressor Engineering Conference. Paper93.hp://docs.lib.purdue.edu/icec/93
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V/.//.////// //.-"/\

...t - CONDUCTOR// // ./ / v / ./ / .... ,/ ,._ -WIRE ENAr1EL

~ C O N N E C T O R MAGNET WIRE &CONNECTOR

BEFORE CRIMPFIG. 1

AFTER CRIMPFIG. 2

1. Visual examination of the connectionboth externally and by sections throughth e connection2. Tensile test of individual wiresfrom th e connector3. Millivolt drop test4. Life test

As nearly as possible, a l l tests are designed tobe functional to th e end us e of th e motor. Oneor more of th e tests covers each of severalcr i t ica l environmental and operating conditionsto which th e connection is subjected. Theseinclude: time; temperature; electric power;physical strength; and kind of atmosphere. Eachof the l isted tests are described in the follow-in g discussion.Visual ExaminationA number of decisions can be made based on visualexaminations. New crimping tools may be found tobe poorly designed i f excessive deformation ofthe wires is found a t th e exi t from the connection.Minimum damage to the wires would warrant furthertesting of that design.sections taken through different locations anddirections in the connector will reveal to whatextent the wire is extruded into th e slots andwhether or not good electr ical contact isobtained. The shape of the crimp can be evaluatedin relat ion to the condition of the wires.Figure 3 shows an idealized connection.

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END VIEW & SECTIONFIG. 3

Tensile Test

SOLID CONDUCTOR

Each wire is pulled in an axial direction fromth e connector, This, in addition to the visualte s t , helps to determine th e effect of crimpheight, shape of crimping tools, and position ofconnector relat ive to the crimping tools. Withproper crimp design, th e strength of theconnected wire a t the connection wil l be verynearly as high as the wire away from theconnection. The Figure 3 i l lustra tes th e us e ofth e la s t two slots as s train re l ief each havingreduced penetration of th e conductor into th econnector slots .The strength of the wire is reduced in proportionto the reduction in cross section area unless i tis mechanically held a t th e flared end of th econnector. Operations required in th e finishingof stators produce bending and tensile stressesin the wires. These stresses may be resistedsuccessfully with a good design, properlymanufactured. . Millivolt Drop TestA common method of measuring th e electr icalquality of a connection is by means of a mill i -volt drop te s t . As shown in Figure 4, inaddition to th e actual connection resistance, th eresistance in th e connector and in th e wire ar eadded together to give a tota l resistance to thecurrent flow. Even though th e connection

1111111111Ml L.L.I VOLT ME.lER

o.c. POWERSUPPLY @AMMETER~ - - - - - - - - - - - - - - - - - - -MILLIVOLT DROP TEST

FIG. '+


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