Grinding Tool Motor Speed Control for Power Reduction
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Solution Overview
Problem
Some grinders continue to operate at constant speed even when not in use or when the tip tool is out of contact with a workpiece, leading to wasteful power consumption and noise generation.
Innovation Solution
A grinding tool with a controller that detects the attachment and gripping of an auxiliary handle, allowing the motor to rotate at a high speed only when the handle is attached and gripped, and reducing speed to a lower speed when no operation is performed or the tip tool is stationary for a predetermined period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the motor rotates at constant speed continuously, then the grinder is always ready for operation, but power consumption and noise generation increase wastefully
Solution Approach 1:
The motor rotational speed is made dynamic rather than fixed. The controller adjusts the motor speed between a first rotational speed (when operation is detected) and a second rotational speed lower than the first (when no operation is detected), allowing the system to adapt its energy consumption to actual usage conditions while maintaining operational readiness when needed
Solution Approach 2:
The system uses detection signals from the handle detector and handle gripping detector to determine whether the grinder is being operated. Based on this feedback, the controller automatically adjusts the motor speed accordingly, creating a closed-loop control system that reduces power consumption during idle periods while ensuring immediate availability when the tool is picked up
2Ease of operation
If the motor rotates at constant speed continuously, then the grinder is always ready for operation, but noise generation increases wastefully
Solution Approach 1:
The motor rotational speed is dynamically adjusted based on operational status. When no operation is detected, the motor operates at a lower second rotational speed, significantly reducing noise generation during idle periods while maintaining the capability to quickly reach full operating speed when needed
Solution Approach 2:
The controller receives real-time feedback from the detection system about whether the grinder is being used. This feedback enables the controller to suppress noise-generating motor operation during idle periods while ensuring the motor is ready to operate at full speed when the tool is picked up, creating a noise-aware operational system
3Use of energy by moving object
If the motor stops completely when not in use, then power consumption is reduced, but the grinder takes time to reach operating speed when picked up
Solution Approach 1:
Instead of complete stoppage, the motor maintains a low idle rotation at the second rotational speed when no operation is detected. This dynamic state allows the motor to consume minimal power while remaining in a ready-to-accelerate condition, eliminating the startup delay when the tool is picked up
Solution Approach 2:
The motor performs a preliminary action by maintaining low-speed rotation during idle periods, keeping the motor and drivetrain in a ready state. This preliminary maintenance of operational capability prevents the time loss that would occur from complete stoppage and subsequent full startup, while still achieving significant power savings compared to continuous full-speed operation
Data Source
AI summary
To reduce wasteful power consumption and noise generation, a control circuit drives a motor in response to a switch being turned on after a handle detector detects attachment of an auxiliary handle and a handle gripping detector detects gripping of the auxiliary handle, controls the motor to rotate at a predetermined first rotational speed in response to the switch being turned on with the attachment and the gripping of the auxiliary handle being detected, and controls the motor to rotate at a second rotational speed lower than the first rotational speed in response to a state of a load on a tip tool being unchanged for a predetermined period of time.