Motor Starter System with Integrated MPU for PLC Wiring Reduction
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Solution Overview
Problem
Existing motor starter systems require complex wiring operations and rely on PLCs for controlling electromagnetic contactors, leading to increased costs, space usage, and reliability issues due to potential PLC failures.
Innovation Solution
A motor starter system that includes external sensor units, a sensing value processing unit for comparing analog sensing values with predetermined references, and a control unit to automatically control the electromagnetic contactor, reducing the need for extensive wiring and enhancing reliability by using RS-485 communication for remote monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a PLC is used to control the electromagnetic contactor, then the motor starter can operate with automated control, but the wiring operations become complex and the cost increases
Solution Approach 1:
The patent extracts the control logic from the PLC and implements it directly in the motor starter unit itself. The microprocessor unit (MPU) is integrated into the motor starter, allowing it to perform automated control functions locally without requiring external PLC intervention, thus simplifying the overall system wiring.
Solution Approach 2:
The patent merges the control functions previously separated between the PLC and motor starter into a single integrated unit. The motor starter now contains both the power control components (contactor, relay) and the intelligent control unit (MPU), eliminating the need for separate PLC wiring connections.
2Extent of automation
If a PLC is used to control the electromagnetic contactor, then the motor starter can operate with automated control, but the cost and space requirements increase
Solution Approach 1:
The patent merges the control functions previously separated between the PLC and motor starter into a single integrated unit. The motor starter now contains both the power control components (contactor, relay) and the intelligent control unit (MPU), eliminating the need for separate PLC wiring connections.
Solution Approach 2:
The motor starter is designed to perform multiple functions within a single device: it provides power control through the contactor, protection through the relay, and intelligent automated control through the integrated MPU. This multi-functionality eliminates the need for separate PLC and auxiliary relay components, reducing both cost and space requirements.
3Loss of information
If an auxiliary relay and auxiliary contact are installed to control the electromagnetic contactor, then the PLC can monitor the contactor state, but the wiring operations increase and reliability decreases
Solution Approach 1:
The patent removes the auxiliary relay and auxiliary contact components from the system. Instead, the MPU directly monitors the electromagnetic contactor state through its built-in sensing capabilities, eliminating the additional wiring and components required for state monitoring while improving reliability.
Solution Approach 2:
The motor starter system performs self-monitoring through the integrated MPU, which automatically detects and reports the contactor state without requiring external auxiliary components. The system serves its own monitoring needs internally, reducing dependency on additional parts and wiring.
Data Source
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AI summary
A motor starter system and a method for operating same are disclosed. According to an embodiment of the present invention, reliability of a motor protection function during an overcurrent is improved by automatically controlling the on/off state of an electromagnetic contactor using an analog sensor value outputted from an external sensor. In addition, the present invention can receive an external sensor value through a connected upper monitoring device, monitor, in real time, the motor starter state, and transmit a control command for directly controlling the on/off state of the electromagnetic contactor, and thus enables excellent operation, integrated lifetime prediction, and motor load management. Furthermore, the present invention can reduce wiring work and a cost thereof and maximizing the use of space more than when controlling the electromagnetic contactor by using the I/O of a PLC.