Fan Motor Torque Control for Clearing Blocked AC Blades
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Solution Overview
Problem
Air conditioning systems, such as heat pumps, often shut down due to ice, snow, or foreign obstacles blocking fan blades, leading to costly and time-consuming servicing and extended disruptions, as conventional units lack the ability to clear these obstructions without manual intervention.
Innovation Solution
Incorporating a rotation sensor and controller that increases the motor's torque when fan blades fail to rotate after an on-command signal, allowing the motor to steadily increase torque up to 40% or 100% of its capacity to free the blades from obstructions, preventing immediate shutdown and enabling continued operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor automatically shuts down when sensing resistance to fan blade rotation, then motor damage is prevented, but the unit requires manual servicing and experiences extended disruption
Solution Approach 1:
The controller applies preliminary torque increase action when rotation is detected to be blocked, attempting to clear the obstruction before shutting down. This preliminary attempt to free the fan blades by increasing torque to 120% of normal operating torque can resolve minor blockages like ice or snow accumulation, avoiding the need for manual service intervention and reducing service disruption time
Solution Approach 2:
The system performs self-service by automatically detecting blocked rotation through the rotation sensor and attempting to clear the blockage itself through torque increase. The controller monitors rotation status and autonomously decides to increase torque to free the blades, eliminating the need for external manual servicing for minor obstructions and maintaining continuous operation
2Object-affected harmful factors
If the motor immediately shuts down upon detecting blocked rotation, then operational safety is maintained, but servicing costs and downtime increase
Solution Approach 1:
Before shutting down, the controller performs a preliminary torque increase to 120% of normal operating torque to attempt clearing the obstruction. This preliminary action addresses minor blockages such as ice, snow, or small foreign objects, preventing the need for service intervention and reducing both servicing costs and downtime while maintaining motor protection through the rotation sensor monitoring
Solution Approach 2:
The system clears its own blockages through automatic torque increase controlled by the rotation sensor. When blocked rotation is detected, the controller autonomously increases torque to free the fan blades, making the system self-servicing for minor obstructions. This reduces the frequency of service calls and associated costs while maintaining operational safety through continuous rotation monitoring
3Reliability
If conventional motors shut down immediately when fan blades are blocked, then damage is prevented, but continuous operation cannot be maintained
Solution Approach 1:
The controller implements a preliminary torque increase to 120% of normal operating torque when blocked rotation is detected, attempting to clear obstructions before shutdown occurs. This preliminary action maintains operational continuity by resolving minor blockages like ice or snow accumulation, allowing the system to continue operating without interruption while the rotation sensor continues to monitor for damage conditions
Solution Approach 2:
The system dynamically adjusts torque based on rotation status. When the rotation sensor detects blocked rotation, the controller dynamically increases torque to 120% of normal operating torque to attempt clearing the obstruction. This dynamic response allows the motor to adapt to blocked conditions and maintain productivity by clearing minor blockages automatically, while still protecting against damage through continuous monitoring
Data Source
AI summary
One aspect provides an air conditioning system that includes a compressor housing, a motor having fan blades rotatably coupled thereto and located within the compressor housing. The motor has a rotation sensor associated with it that is configured to sense a rotation of the fan blades. This embodiment further comprises a controller coupled to the motor and is configured to increase a torque of the motor when the rotation sensor indicates that the fan blades are not rotating after an on command signal is received by the motor.