Patent RU-2516276-C1 (RU)
Inventor: SMIRNOV GENNADIJ VASIL EVICH
IPC: H02K15/12
Filed: 2013-01-10
Granted: 2014-05-20
Abstract: FIELD: electricity. 
     SUBSTANCE: batch of samples is prepared preliminary for an impregnating compound with different degree of dryness for each sample and dependency of the dielectric permittivity on frequency of the electromagnetic field is defined for the above samples. According to the defined dependencies two measurement frequencies are selected, one frequency f 1  lies in a dispersion region of the non-hardened insulating impregnating compound while the other frequency f 2  lies in an optical region of the non-hardened insulating impregnating compound. Using the defined frequency dependencies for the samples dryness and the dielectric permeability curves for the impregnating compound are plotted as            lg     ε     i   c         (       f   2       )         lg     ε     i   c         (       f   1       )         ,         
 where ε ic (f 1 ) ε ic (f 2 ) are values of the dielectric permeability for the impregnating compound measured at frequencies f 1  and f 2  of the electromagnetic field respectively. Thereafter for each controlled winding capacitance-to-case values C bi (f 1 ) and C bi (f 2 ) for two selected frequencies before impregnation and capacitance values after impregnation and drying C ai (f 1 ) and C ai (f 2 ) are measured, and according to the measurement results the following ratio is calculated                lgε       ic         (       f   2       )             lgε       ic         (       f   1       )         =           lnC       ai           (f     2     )   +       ln[C       eq         (       f   2       )     −     C     bi         (       f   2       )     ]   −       lnC       bi         (       f   2       )     −       ln[C       eq         (       f   2       )     −     C     ai         (       f   2       )     ]           lnC       ai           (f     1     )   +       ln[C       eq         (       f   1       )     −     C     bi         (       f   1       )     ]   −       lnC       bi         (       f   1       )     −       ln[C       eq         (       f   1       )     −     C     ai         (       f   1       )     ]       ,         
 where          C     eq         (       f   1       )     =           2pSε     0       ε   e       (       f   1       )       ε   f       (       f   1       )             3[d     e       ε   f       (       f   1       )     +     d   f       ε   e       (       f   1       )         ,                   C     eq         (       f   2       )     =           2pSε     0       ε   e       (       f   2       )       ε   f       (       f   2       )             3[d     e       ε   f       (       f   2       )     +     d   f       ε   e       (       f   2       )               
 are equivalent capacitance values for the in-series enamel and frame insulation capacitance for the controlled winding at frequencies f 1  and f 2  of the electromagnetic field respectively, p is a number of slots in the magnet core to which the controlled part of the winding is inserted; S is a square area of the slot; ε 0 =8.854187·10 -12  is an electric constant; ε e (f 1 ), ε e (f 2 ), are the dielectric capacitance values for the enamel film of the winding wire at frequencies f 1  and f 2  of the electromagnetic field respectively; ε f (f 1 ), ε f (f 2 ) are the dielectric capacitance values for the frame insulation at frequencies f 1  and f 2  of the electromagnetic field respectively; d e  is thickness of the enamel insulation of the wire; d f  is thickness of the frame insulation; thereafter according to measurement results of            lg     ε     i   c         (       f   2       )         lg     ε     i   c         (       f   1       )               
 value dryness degree of the insulating compound in each controlled winding is determined against the dryness curve. 
     EFFECT: excluding necessity of self-capacitance measurements for windings at three frequencies with use of reference inductance with simultaneous and essential simplifying of measurements due to exclusion of manufacture and use for the purpose of control of such elements as a current stabiliser, a heating time metre and metre of windings temperature increment in heating process. 
     1 tbl, 4 dwg asd - as