Vacuum Pump Control Using Current and Rotor Speed for Failure Risk
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Solution Overview
Problem
Conventional vacuum pumps, particularly turbo-molecular pumps, face breakage risks due to rotor overheating, which cannot be adequately prevented by existing protective functions, and incorporating rotor-blade temperature sensors increases costs.
Innovation Solution
A vacuum pump system that determines risk of rotor failure based on current and rotational speed measurements, without the need for temperature sensors, using defined regions and a risk calculation method to trigger protective measures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rotor-blade temperature sensor is introduced to prevent rotor destruction, then the accuracy of overheating detection is improved, but the cost of the vacuum pump increases
Solution Approach 1:
The patent replaces the mechanical/physical temperature sensor measurement system with an electrical measurement system. Specifically, it uses a current sensor to measure motor current and a rotational speed sensor to measure rotor speed, then calculates temperature risk through computational logic rather than direct thermal measurement. This substitution achieves accurate overheating detection without the cost and complexity of temperature sensors.
Solution Approach 2:
The patent introduces an intermediary calculation system that uses motor current and rotational speed as proxy indicators for rotor temperature. Instead of measuring temperature directly, the system measures these intermediate electrical and mechanical parameters and derives temperature risk information through region determination and risk degree calculation, effectively using intermediaries to indirectly assess the target parameter.
2Device complexity
If conventional protective functions are used to prevent pump breakage, then the device complexity is reduced, but the reliability of preventing rotor destruction deteriorates
Solution Approach 1:
The patent implements preliminary action by detecting abnormal conditions (high current and low rotational speed combinations) before they lead to actual rotor destruction. The system continuously monitors motor current and rotational speed, determines risk regions in advance, and triggers protective stopping before thermal damage occurs, preventing the harmful outcome rather than merely responding to it.
Solution Approach 2:
The patent establishes a feedback loop where motor current and rotational speed are continuously measured, processed through region determination and risk degree calculation, and used to trigger protective actions when thresholds are exceeded. This closed-loop feedback system dynamically adjusts protection based on real-time operating conditions, significantly improving reliability over conventional static protective functions.
3Productivity
If the vacuum pump operates continuously without risk assessment, then the productivity is maintained, but the risk of rotor destruction increases
Solution Approach 1:
The patent applies dynamics by making the protective function adaptive rather than static. The risk degree threshold and protective actions are dynamically adjusted based on real-time motor current and rotational speed measurements. The system continuously updates region determination and risk assessment, allowing flexible response to changing operating conditions while maintaining continuous productivity.
Solution Approach 2:
The patent uses parameter changes by monitoring variations in motor current and rotational speed to assess temperature risk. When these parameters enter high-risk regions (combinations of high current and low rotational speed), the system triggers protective measures. This parameter-based approach enables continuous operation with dynamic safety adjustments rather than fixed operational constraints.
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 rotor destruction by detecting abnormal conditions and stopping the pump operation before failure occurs, reducing costs by avoiding temperature sensor implementation.
Implementation Method 1
a motor that rotates/drives the rotor blade
Implementation Method 2
a magnetic bearing device for magnetically floating/controlling a rotating body
Data Source
AI summary
A vacuum pump including: a current measuring means that measures a current flowing through a motor, in which a first region defined such that a current measured value flowing through the motor is equal to or larger than a current specified value and a rotational speed measured value of a rotor blade is equal to or larger than a rotational speed specified value, a second region defined such that the current measured value flowing through the motor is less than the current specified value or the rotational speed measured value of the rotor blade is less than the rotational speed specified value, a region determining means that determines which region a rotational speed measured value and the current measured value belong, and a calculating means that calculates a risk degree of a failure of the vacuum pump with elapse of time based on the determination by the region determining means.