Welding Power Supply Interlock for High-to-Low Voltage Isolation
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Solution Overview
Problem
Welding-type power supplies often face the challenge of preventing high voltage from being applied to low voltage outputs, which can damage sensitive equipment due to equipment failures or user errors.
Innovation Solution
The implementation of a mechanical interlock system that uses auxiliary switches and contactors to prevent the welding voltage output from transmitting to the battery charge output, ensuring that high voltage is not applied to low voltage circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a welding-type power supply provides multiple voltage outputs from a single system, then the versatility and power utilization are improved, but the risk of high voltage damaging low voltage equipment increases
Solution Approach 1:
The patent divides the power supply system into separate high voltage and low voltage circuits with distinct contactors (first contactor for high voltage, second contactor for low voltage). This segmentation allows independent control of each voltage level, preventing high voltage from inadvertently reaching low voltage equipment while maintaining the ability to provide multiple voltage outputs.
Solution Approach 2:
The patent introduces an auxiliary switch as an intermediary component that monitors the state of the first contactor (high voltage) and automatically controls the second contactor (low voltage). This intermediary mechanism ensures that when high voltage is present, the low voltage circuit is automatically disconnected, preventing damage without requiring user intervention.
2Device complexity
If manual intervention is required to prevent high voltage on low voltage output, then the system simplicity is maintained, but the operational safety and reliability decrease
Solution Approach 1:
The patent implements a self-service safety mechanism where the auxiliary switch automatically monitors the high voltage contactor state and controls the low voltage contactor accordingly. The system protects itself by automatically disconnecting the low voltage circuit when high voltage is detected, eliminating the need for user intervention while maintaining simplicity in operation.
Solution Approach 2:
The auxiliary switch creates a feedback loop between the high voltage and low voltage circuits. It continuously monitors the state of the first contactor and uses this information to control the second contactor, ensuring that the low voltage output is only enabled when the high voltage circuit is safely disconnected. This automatic feedback mechanism significantly improves operational safety.
3Object-affected harmful factors
If an interlock system is implemented to prevent high voltage transmission, then the equipment protection is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the safety function into a separate auxiliary switch component that is operatively coupled to but independent from the main contactors. This extraction allows the interlock function to be added without fundamentally redesigning the power supply architecture, minimizing the increase in overall system complexity while achieving robust equipment protection.
Data Source
AI summary
Systems and methods for a welding-type power supply to provide both a welding output voltage and a battery charging output voltage. The power supply includes a first contactor associated with a first circuit to provide the welding output voltage, and a second contactor associated with a second circuit to provide the battery charging output voltage. An auxiliary switch is operatively coupled to the second contactor, to prevent the first circuit from closing when the second contactor is closed to prevent transmission of the welding output voltage to the second circuit.