Analysis of Eddy Current Losses on Surface of Submersible Motor with Different Stator Slot Types at No-Load Condition

Abstract

Abstract:

Due to the special operation conditions, the stator of submersible motor is generally adopted closed-type-slot. In this paper, the rotor eddy currents as well as the rotor eddy current losses at no-load condition in a submersible motor which consist of the closed-slot stator and closed-slot rotor were investigated. Analytical method was developed to evaluate the Carter Factor, the air-gap permeance, the tooth harmonic fields caused by stator slotting, and the eddy current losses on rotor surface. The magnetic fields especially the tooth harmonic fields caused by slotting effect in four stator slot models were analyzed by the transient two-dimensional finite element method (2D FEM). Full-open slot model and semi-open slot model were constructed to make a comparison with the original slot model. Then the stator tooth harmonic fields caused by stator slotting were separated from the total stator tooth harmonics by vector composition method. The rotor eddy currents as well as the rotor eddy current losses of the models with different stator slot types were analyzed. There is a little difference between the analytical results and the FEM results since the FEM method considered the magnetic saturation and material nonlinearity. Finally, it is found that the rotor surface loss of the model with improved stator slots is much smaller than that of the model with open slots and original slots.

Key words: Eddy current losses, finite element method, no-load condition, tooth harmonic fields

CLC Number:

TM301

Bao Xiaohua,Liang Na,Fang Yong,Li Fuying. Analysis of Eddy Current Losses on Surface of Submersible Motor with Different Stator Slot Types at No-Load Condition[J]. Journal of Electrical Engineering, 2015, 10(6): 7-18.

Figures/Tables 21

References 25

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Harmonic order	Amplitude of forward-rotating tooth harmonic field/T
Harmonic order	Full-open slot	Semi-open slot
1st order	0.151	0.070
2nd order	0.085	0.060
3rd order	0.014	0.056
4th order	0.031	0.046
5th order	0.035	0.034
Total	0.188	0.186

	Rotor surface loss/W
	Analytical	FEM
Full-open slot	155.6	235.8
Semi-open slot	71.6	89.0
Original slot	0	48.2
Improved slot	0	14.1

Item	Specification
Rated power/kW	30
Rated voltage/V	380
Pole pairs	3
Connection type	Y
Outer diameter of stator/mm	590
Inner diameter of stator/mm	445
Outer diameter of rotor/mm	443.4
Core length/mm	68
Number of stator slots	54
Number of rotor slots	58