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Centrifugal Advance Device For High Voltage Limitation Of Downhole Alternator

IP.com Disclosure Number: IPCOM000199502D
Publication Date: 2010-Sep-07
Document File: 1 page(s) / 8K

Publishing Venue

The IP.com Prior Art Database

Abstract

The voltage of a permanent magnet alternator is normally linearly dependent on the rotor speed. High speed causes high voltage which potentially can destroy the electronics of a downhole tool even if the electronics is switched off. A Centrifugal Advance Device (CAD) limits high voltages of an alternator without affecting the speed. The limitation of the voltage leads to a wider operating range (that means a wider flow rate range for the customer to pump through the tool) and / or a better safety margin. The centrifugal advance device affects the geometry of the magnets which are placed on the rotor. The invention is an additional mechanical effort to reduce problems on the electronical side. This specially makes sense when electronics for very high temperatures have to be developed. The invention has two approaches: 1. movable magnet section on a rotor shaft 2. special centrifugal advice which is applicable for downhole tools.

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Title of Invention:

Centrifugal Advance Device For High Voltage Limitation Of Downhole Alternator

Abstract of the Invention:

The voltage of a permanent magnet alternator is normally linearly dependent on the rotor speed. High speed causes high voltage which potentially can destroy the electronics of a downhole tool even if the electronics is switched off. A Centrifugal Advance Device (CAD) limits high voltages of an alternator without affecting the speed. The limitation of the voltage leads to a wider operating range (that means a wider flow rate range for the customer to pump through the tool) and / or a better safety margin. The centrifugal advance device affects the geometry of the magnets which are placed on the rotor. The invention is an additional mechanical effort to reduce problems on the electronical side. This specially makes sense when electronics for very high temperatures have to be developed. The invention has two approaches: 1. movable magnet section on a rotor shaft 2. special centrifugal advice which is applicable for downhole tools.