Three-Phase Frequency-Dependent Network Equivalents in the ATP for Lumped Parameter Systems Using Descriptor Formulation, Rational Models, and Symmetrical Component Data

Author(s):  
T. M. Campello ◽  
S. L. Varricchio ◽  
G. N. Taranto
2021 ◽  
Vol 23 (2) ◽  
pp. 87-94
Author(s):  
Mahdi Atig ◽  
Mustapha Bouheraoua ◽  
Rabah Khaldi

The aim of this paper is to estimate the induction motor temperature at both steady and transient thermal states under healthy and faulty conditions. The distribution of the temperature in the motor is calculated using thermal models based on the 2D Lumped Parameter Thermal Network (LPTN). The thermal model takes into account the heat sources, convection heat transfer and the thermal resistances in the motor. The heat flow generated by the conduction and convection in a three-phase squirrel cage induction motor is discussed. The developed model is used to study the motor thermal behavior during the opening phase situation. The results obtained by the model developed are validated by experimental tests. The tested machine is a standard three-phase, 4-pole, 2.2 kW, 380 V squirrel cage induction motor of Totally Enclosed Fan Cooled “TEFC” design manufactured in Algeria by Electro-Industries company. The simulated temperatures so obtained are in good agreement with the measured ones, and the 2D Lumped Parameter Thermal Network study seems to be appropriate to characterize the heating of the active parts of the machine under different operating conditions.


1994 ◽  
Vol 116 (4) ◽  
pp. 686-693 ◽  
Author(s):  
K. T. Millsaps ◽  
M. Martinez-Sanchez

A theoretical and experimental investigation on the aerodynamic forces generated by a single gland labyrinth seal executing a spinning/whirling motion has been conducted. A lumped parameter model, which includes the kinetic energy carryover effect, is presented along with a linear perturbation solution technique. The resulting system is nondimensionalized and the physical significance of the reduced parameters is discussed. Closed-form algebraic formulas are given for some simple limiting cases. It is shown that the total cross force predicted by this model can be represented as the sum of an ideal component due to an inviscid flow with entry swirl and a viscous part due to the change in swirl created by friction inside the gland. The frequency-dependent ideal part is solely responsible for the rotordynamic direct damping. The facility designed and built to measure these frequency dependent forces is described. Experimental data confirm the validity and usefulness of this ideal/viscous decomposition. A method for calculating the damping coefficients based on the force decomposition using the static measurements only is presented.


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