Portable Class-II Lubrication Without Earth Connection
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Solution Overview
Problem
Existing lubrication devices for wind turbines and other systems without a common earth connection require an earth connection for safety, making them unsafe for use in environments without a protective earth connection, and frequency converters used for speed regulation are class-I appliances that necessitate an earth connection, limiting their use as class-II devices.
Innovation Solution
A class-II lubrication device is designed using a combination of a class-II power supply and a motor controller, eliminating the need for an earth connection by ensuring all components operate at Extra-Low Voltages (ELV) of 50 Volts AC or 120 Volts DC, with double insulation to ensure safety, and replacing the frequency converter with a motor controller for speed regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a frequency converter is used for speed regulation, then motor speed control is achieved, but an earth connection is required which limits use in class-II devices
Solution Approach 1:
The patent removes the frequency converter component entirely from the system. Instead of using a frequency converter for motor speed control, the invention employs a class-II power supply with integrated motor control capabilities that do not require an earth connection, thereby extracting the problematic component while retaining the desired speed control function.
Solution Approach 2:
The patent replaces the electrical frequency converter system with a class-II power supply system that uses alternative control methods. The class-II power supply incorporates motor control functionality that achieves speed regulation without relying on frequency conversion, substituting the traditional electrical control approach with a safer alternative suitable for class-II devices.
2Reliability
If class-I appliances are used, then safety through earth connection is provided, but portability and use in environments without earth connection is limited
Solution Approach 1:
The patent changes the electrical safety parameters by transitioning from class-I to class-II protection. This involves modifying the power supply design to provide enhanced insulation and double protection, allowing the device to operate safely without an earth connection. The parameter change enables the device to be used in portable applications and environments where earth connection is unavailable.
3Reliability
If voltage is reduced to Extra-Low Voltage, then safety without earth connection is achieved, but power output is limited
Solution Approach 1:
The patent optimizes the power supply parameters to deliver maximum possible power within the Extra-Low Voltage constraints. By carefully selecting operating voltages (24V AC or 48V DC) and designing efficient power conversion circuits, the system achieves adequate power output for lubrication pump operation while maintaining safety through class-II protection and enhanced insulation.
Data Source
AI summary
The present disclosure relates to a portable Extra-Low Voltage (ELV) class-II lubrication device comprising: at least one class-II power supply; at least one electric motor controller powered by the at least one power supply; at least one electric motor controlled by the at least one motor controller; at least one pump activated by the at least one electric motor and connected to at least one lubricant container, the pump configured to pump a lubricant from the at least one container to at least one target to be lubricated, wherein an output voltage of the at least one power supply and an output voltage of the at least one motor controller and an operating voltage of the at least one motor is equal to or less than 50 Volts AC or 120 Volts DC.