Electricity: measuring and testing – Impedance – admittance or other quantities representative of... – Lumped type parameters
Patent
1992-12-04
1995-05-30
Wieder, Kenneth A.
Electricity: measuring and testing
Impedance, admittance or other quantities representative of...
Lumped type parameters
324545, G01R 104
Patent
active
054205239
ABSTRACT:
There is disclosed an apparatus and method for determining locked rotor test data for three-phase alternating current motor without mechanically coupling the rotor to any instrumentality. The "locked rotor" test is conducted by connecting a source of single-phase alternating current with a variable frequency to the field windings of a three-phase a.c. motor. The frequency of the voltage source is varied from approximately the rated frequency to a lower frequency and the input electrical power and the input voltage are recorded at two or more data points defined by two or more frequencies between the rated frequency and 0. The single-phase input power data and the single-phase input voltage data is then scaled by a scaling factor to convert it to equivalent three-phase locked rotor data. Particularly, the single-phase input power is multiplied by 1.515 to convert it to equivalent three-phase input power, and the single-phase input voltage is multiplied by 0.860 to convert it to equivalent three-phase input voltage. By carrying out conventional stray load loss testing using a dynamometer off-line, by using a conventional no load test, and by measuring the d.c. resistance of the primary field windings, that data along with the single-phase " locked rotor" data can be used in an "Equivalent Circuit Method" calculation disclosed in Japanese Standard JEC-37 (1979) to determine the number of performance parameters for the three-phase a.c. motor.
REFERENCES:
patent: 5049815 (1991-09-01), Kliman
Cobosco Chester J.
Saini Harjit S.
Walker Joel B.
Wallace Stanley E.
Bowser Barry
Reliance Industrial Company
Wieder Kenneth A.
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