Non-Intrusive Capacitive Voltage Sensor for Motor Monitoring

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Solution Overview

Problem

Measuring voltage in voltage lines of electric motors and generators is time-consuming and expensive due to the need to remove non-conductive insulation for direct access.

Innovation Solution

A non-intrusive capacitive voltage sensor system that attaches to the insulator surrounding the metal conductor without removing the insulation, using a signal plate and shield plate to sense and block electromagnetic interference, allowing for voltage monitoring and control without disrupting the insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If direct access to the conductor is obtained by removing insulation, then voltage measurement accuracy is improved, but installation time and cost increase

Engineering Contradiction:

Improvevoltage measurement accuracyVSAvoidinstallation time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent introduces an intermediary capacitive sensing mechanism that measures voltage through the insulation without direct contact. The sensor uses capacitance coupling to detect voltage on the conductor through the insulating layer, acting as a mediator that enables measurement without removing the insulation barrier.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical approach of physically removing insulation with a field-based capacitive sensing method. Instead of mechanically accessing the conductor, the system uses electromagnetic field coupling through the insulation to achieve voltage measurement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If insulation is removed for voltage measurement, then access to the conductor is improved, but manufacturing cost increases

Engineering Contradiction:

Improveconductor accessVSAvoidmanufacturing cost

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

The insulation is repurposed from a barrier to be measured into a functional component of the sensing system. The capacitive sensor utilizes the insulation's dielectric properties to enable non-contact voltage measurement, transforming the insulation from an obstacle into an intermediary medium for measurement.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sensor creates an electrical copy or representation of the conductor's voltage state through capacitive coupling. Rather than directly accessing the conductor, the sensor measures an equivalent electrical signal that is coupled through the insulation, providing a copy of the voltage information without physical contact.

Inventive Principle:

Principle #26Copying

3Device complexity

If non-intrusive sensing is used, then installation complexity is reduced, but susceptibility to electromagnetic interference increases

Engineering Contradiction:

Improveinstallation complexityVSAvoidelectromagnetic interference susceptibility

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the potentially harmful effect of electromagnetic fields into a useful sensing mechanism. The capacitive sensor exploits electromagnetic field coupling to achieve non-intrusive measurement, turning what could be interference into the basis for voltage detection through the insulation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The insulation serves as a protective intermediary that isolates the sensor from direct electromagnetic interference while still allowing capacitive coupling. This intermediary layer filters out harmful direct contact interference while permitting the desired voltage signal to be sensed through capacitance.

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables efficient and cost-effective monitoring and control of voltage in voltage lines by reducing the need for insulation removal, allowing for real-time voltage detection and control of electrical rotating machines.

Implementation Method 1

a non-intrusive capacitive voltage sensor configured to couple to an insulator surrounding a metal conductor, wherein the non-intrusive capacitive voltage sensor is configured to produce a voltage signal indicative of a voltage in the metal conductor

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Implementation Method 2

a first shield plate extending over the first signal plate, wherein the first shield plate is configured to block electromagnetic interference

Methodology Applied

Scientific EffectElectromagnetic shielding: Faraday Cage

Data Source

PatentUS9513316B2System and method for a capacitive voltage sensor system

Publication Date: 2016.12.06 BAKER HUGHES CO

AI summary

A system including a non-intrusive capacitive voltage sensor configured to couple to an insulator surrounding a metal conductor, wherein the non-intrusive capacitive voltage sensor is configured to produce a voltage signal indicative of a voltage in the metal conductor, and a monitor-controller system configured to receive the voltage signal from the non-intrusive capacitive voltage sensor, wherein the monitor-controller system is configured to use the voltage signal to monitor or control a machine.