Fan Motor Startup Speed Control for Low-Temperature Noise
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Solution Overview
Problem
Fan motors with impregnated bearings are prone to abnormal noise due to lubricant shrinkage, especially in low temperature environments, where the lubricant impregnation is insufficient, leading to inadequate lubrication and friction between the bearing and shaft.
Innovation Solution
A fan control system that includes a controller capable of selecting between a first mode and a second mode, where the second mode operates the fan motor at a lower rotation speed initially to warm the impregnated bearing and prevent lubricant contraction, thereby reducing the likelihood of abnormal noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fan motor operates at high rotation speed from the start, then productivity is improved, but the lubricant in the impregnated bearing contracts and causes abnormal noise
Solution Approach 1:
The controller operates the fan motor at a low rotation speed during a predetermined period after power supply is turned on, before switching to normal operation mode. This preliminary low-speed operation prevents lubricant contraction and ensures proper lubrication is established before high-speed operation begins, thereby preventing abnormal noise while maintaining productivity.
2Reliability
If the impregnation amount of lubricant is increased, then reliability is improved, but the device complexity increases
Solution Approach 1:
Instead of increasing the impregnation amount of lubricant in the bearing structure, the invention changes the operational parameters by controlling the rotation speed profile. The controller adjusts the rotation speed to be low during the initial period, which prevents lubricant contraction and ensures adequate lubrication without requiring increased lubricant impregnation or more complex bearing structures.
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
The system effectively minimizes abnormal noise and lubricant-related defects by warming the impregnated bearing through reduced initial rotation speed, ensuring consistent lubrication even in low temperature conditions.
Implementation Method 1
the lubricant impregnated in the impregnated bearing realizes a lubricating action between the impregnated bearing and the shaft
Implementation Method 2
a defect such as abnormal noise due to shrinkage of the lubricant may occur under a special environment such as a low temperature environment
Data Source
AI summary
A fan control system according to the present disclosure includes a controller that selects a control mode from a plurality of control modes including a first mode and a second mode. The first mode is a control mode in which an electric signal is given to fan motor so that fan motor operates at the first rotation speed. The second mode is a control mode in which an electric signal is given to fan motor so that fan motor operates at a second rotation speed lower than the first rotation speed. The controller has a function of selecting the second mode in a period after the start of the fan motor and before the selection of the first mode.