Motor Terminal Disconnection Detection During Powered Operation
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Solution Overview
Problem
Existing HVAC systems lack an efficient and reliable method to detect motor disconnections at terminals, which can lead to unstable operation of motor-driven components and potential damage due to irregular voltage/current.
Innovation Solution
A system comprising a motor, motor drive circuit, and processor is used to detect motor disconnections by evaluating current values and motor parameters while the motor is switched off or on, utilizing a sensor-less algorithm to determine terminal connectivity through a circuit model and threshold comparisons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If motor disconnection detection is implemented using conventional methods, then the system can detect disconnections, but the detection reliability is insufficient and cannot reliably identify disconnections while the motor is running
Solution Approach 1:
The patent replaces conventional current-based detection methods with a magnetic field-based detection system. The Hall effect sensor detects the position of the permanent magnet in the rotor, providing reliable disconnection detection while the motor is running without relying on current measurements that become unreliable during operation.
Solution Approach 2:
The patent introduces a Hall effect sensor as an intermediary device to detect the magnetic field position of the permanent magnet. This intermediary provides indirect but reliable information about motor connectivity and operational state, enabling accurate disconnection detection during motor operation.
2Device complexity
If the motor operates without disconnection detection, then the system is simpler, but the motor-driven components become unstable and may be damaged by irregular voltage/current
Solution Approach 1:
The motor control system performs self-diagnosis by continuously monitoring the position of the permanent magnet through the Hall effect sensor. The system can automatically detect disconnections and alert operators without requiring external monitoring equipment, maintaining component stability while adding minimal complexity.
3Device complexity
If conventional detection methods are used, then the system structure is simpler, but the ability to detect disconnections while the motor is switched on is lost
Solution Approach 1:
The patent replaces electrical current-based detection with magnetic field-based detection using a Hall effect sensor. This substitution enables continuous real-time monitoring of motor connectivity during operation, as the magnetic field position can be detected regardless of the motor's operational state.
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 detects motor disconnections at terminals, ensuring stable operation of motor-driven components and preventing damage by identifying and addressing disconnections promptly.
Implementation Method 1
A Hall effect sensor of the motor is communicatively coupled with the controller
Data Source
AI summary
A system for detecting motor disconnections while a motor is switched on comprises a motor, a motor drive circuit, and a processor. The processor determines whether a set of disconnection conditions is met for more than a threshold time. In this process, the processor determines that a pulse signal that leads to power the motor is enabled, that a speed associated with the motor is more than a threshold speed, a drive voltage output associated with the motor drive circuit is more than a threshold voltage, a current applied to the motor is less than a threshold current, and that the speed associated with the motor is zero. The processor determines that at least one terminal of the motor is disconnected from the motor drive circuit in response to determining that the set of disconnection conditions is met for more than the threshold time.