Rotor Dynamic Analysis of an Eccentric Hydropower Generator With Damper Winding for Reactive Load

• Asymmetry in the magnetic circuit, around the air gap circumference, in a hydroelectric generator will give rise to a unbalanced magnetic pull. In this paper a hydropower rotor system is modeled and the influence of electro-mechanical forces due to overexcitation is analyzed The active power has been kept constant and the rotor excitation has been changed in order to vary the output of reactive power The electromagnetic field is solved with the finite element method Two electromagnetic models are compared: one with and one without damper winding. The mechanical model of the generator consists of a four id disk connected to an elastic shaft su orted b two bearin s de rees of freedom ri pp y g g g with linear properties. It has been found that the unbalanced magnetic pull slightly increasesfor reactive loads resulting in a decrease of natural frequencies and an increase of unbalance response. When the damper winding is included, the magnetic pull will decrease compared to the model without damper winding, and the pull force has two components: one radial and one tangential. The tangential component can influence the stability of the mechanical system for a range of design parameters.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Annan maskinteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Other Mechanical Engineering (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Teknisk mekanik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Applied Mechanics (hsv//eng)

Nyckelord

hydroelectric generators

rotors

machine windings

magnetic circuits

machine theory

magnetic forces

electromagnetic fields

finite element analysis

machine bearings

shafts

NATURAL SCIENCES

NATURVETENSKAP

Datorstödd maskinkonstruktion

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