Hall Effect Power Sensor for Hoist Motor Protection
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Solution Overview
Problem
Hoisting devices used in building maintenance face hazards due to unintended high-low current cycling conditions, leading to potential motor damage and safety risks from excessive voltage drops and insufficient starting voltage, which existing technologies fail to adequately detect and manage.
Innovation Solution
A system utilizing a Hall Effect Device (HED) for current sensing, integrated with a microprocessor to monitor voltage and current, detects operating conditions and prevents hazards by interrupting power supply when excessive current is detected, employing a non-destructive resettable fuse and providing operator warnings or shutdowns for unsafe conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing current sensing methods (thermal overload devices, conventional current transformers) are used to monitor power and interrupt supply during fault conditions, then motor protection is provided, but the system cannot adequately detect and manage unintended high-low current cycling conditions that lead to motor damage
Solution Approach 1:
The patent replaces conventional thermal overload devices and current transformers with a Hall Effect Device (HED) that provides electronic sensing of current. This substitution enables precise detection of current cycling conditions that lead to motor damage, while maintaining motor protection capabilities. The HED outputs a voltage signal proportional to the current magnitude, allowing the microprocessor to accurately monitor and detect unintended high-low current cycling that previous mechanical or electromagnetic devices could not adequately identify.
2Measurement precision
If Hall Effect Devices are supplied with voltage representative of Vt to enable real power measurement, then the signal output becomes representative of real power, but the device complexity increases
Solution Approach 1:
The patent implements a multi-functional system where the Hall Effect Device serves dual purposes: it provides both current measurement and real power measurement capabilities. By supplying the HED with voltage representative of Vt, the device outputs a signal that contains information about both current magnitude and real power. The microprocessor processes this single output signal to derive both current and power measurements, eliminating the need for separate sensing circuits and reducing overall system complexity despite the enhanced measurement capabilities.
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
Effectively prevents motor damage and ensures operator safety by accurately estimating load conditions and managing power delivery to hoisting devices, reducing the risk of hazards and potential emergencies.
Implementation Method 1
Hall Effect Devices may be used to sense magnetic flux resulting from a flow of current through a conductor
Implementation Method 2
Some of these known devices have used a flux concentrator to concentrate magnetic flux emanating from the flow of current through a conductor
Data Source
AI summary
Disclosed is an apparatus, system, and method for sensing the current supplied to a motorized hoist for raising a maintenance platform and providing an estimate of the operating status of the motor, for example, as stopped, starting, stalled or operating as expected. In various embodiments, measures of voltage and current may be used to determine the operating condition of the hoist and to estimate the magnitude of the applied load. Unintended modes of operation can then be determined so that the conditions can be indicated to the operator and protective measures taken.