Automatic Pump Motor Speed Control via Stator Winding Switching
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Solution Overview
Problem
Conventional automatic pumps face inefficiencies due to constant motor speed, frequent energy wastage from pressure switch fluctuations, and bulkiness and high cost associated with inverter usage.
Innovation Solution
An automatic pump design featuring a motor capable of multi-stage rotational speeds, controlled by a pressure sensor and switching unit that adjusts stator coil winding counts to match fluid demand, eliminating the need for inverters and optimizing energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an inverter is installed to control motor speed according to internal pressure, then motor speed control capability is improved, but manufacturing cost and device volume increase
Solution Approach 1:
The patent extracts the speed control function from the inverter and implements it through a simpler switching unit that selectively connects different stator coil winding counts. This removes the need for a complex inverter while maintaining the essential speed control capability through discrete multi-stage speeds.
Solution Approach 2:
The patent replaces the expensive inverter with a cost-effective switching unit composed of simple switches and resistors. Although the inverter provides continuous speed control, the switching unit achieves sufficient performance for multi-stage control at a fraction of the cost and complexity.
2Adaptability or versatility
If an inverter is installed to control motor speed according to internal pressure, then motor speed control capability is improved, but manufacturing cost increases
Solution Approach 1:
The patent extracts the speed control function from the inverter and implements it through a simpler switching unit that selectively connects different stator coil winding counts. This removes the need for a complex inverter while maintaining the essential speed control capability through discrete multi-stage speeds.
Solution Approach 2:
The patent replaces the expensive inverter with a cost-effective switching unit composed of simple switches and resistors. Although the inverter provides continuous speed control, the switching unit achieves sufficient performance for multi-stage control at a fraction of the cost and complexity.
3Device complexity
If constant speed motor is used, then device complexity is reduced, but pump efficiency deteriorates due to inability to control impeller rotation speed
Solution Approach 1:
The patent makes the motor speed dynamic by enabling it to switch between multiple rotational speeds based on pump operating conditions. The switching unit responds to pressure sensor feedback and automatically adjusts the motor speed to match the required fluid discharge rate, optimizing pump efficiency across varying conditions.
Solution Approach 2:
The patent implements a feedback control system where the pressure sensor continuously monitors internal pressure and feeds this information to the switching unit. The switching unit then adjusts the motor speed accordingly, creating a closed-loop system that maintains optimal pump efficiency without requiring complex control electronics.
4Ease of manufacture
If pressure switch is used to control motor operation, then cost is reduced, but energy wastage increases due to frequent motor on-off cycles
Solution Approach 1:
The patent uses periodic sampling of pressure data at multiple thresholds to determine motor operation. Instead of simple on-off control, the system continuously monitors pressure and switches motor speeds periodically based on pressure changes, reducing unnecessary start-stop cycles while maintaining energy efficiency.
Solution Approach 2:
The patent changes the control parameter from binary (on/off) to multi-level (multiple speed stages). By controlling the motor to operate at different rotational speeds rather than simply on or off, the system reduces energy wastage while maintaining simple and cost-effective control architecture.
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
This solution reduces manufacturing costs and pump size by dynamically controlling motor speed based on internal pressure, enhancing efficiency and reducing energy wastage.
Implementation Method 1
a pressure sensor for sensing an internal pressure of the housing and transmitting the internal pressure to the control unit
Implementation Method 2
selectively changing winding counts of a stator coil of the motor and thereby running the motor at one of set multi-stage rotational speeds
Data Source
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AI summary
An automatic pump and an operation control method for the same are disclosed. The disclosed pump and method operate in response to fluctuations in the internal pressure of a housing forming a fluid path inside the automatic pump for making selective switching connections with variable winding counts of a stator coil of the pump motor and thereby shifting the rotational speed of the motor to an appropriate one of multi-stage rotational speeds or stop the motor. Such a consequently obviated inverter used in conventional automatic pumps offers cost reduction and pump compactness.