| Overload relay is divided into thermal overload relay and electronic overload relay which are widely used in various motors to protect circuits.This paper designed a new-style of thermoelectric overload protection relay which provided a new idea for fault protection and development of overload relay based on advantages and disadvantages of thermal overload relay and electronic overload relay.Firstly,the paper designed a thermoelectric overload protection relay based on JR36-20 overload relay.Not only can this relay realize a single-phase protection for motors,but also it can realize three-phase protection for motors by overlaying application.Because of separate collection of various signals,the relay can realize the phase-deficient fault protection except thermal overload protection such as ground protection and open-phase protection.Not only will thermoelectric overload protection relay disassemble a traditional three-phase thermal overload relay into three separate units,but also it separates heating units from releasing units which effectively avoids interaction among temperature field of various units.Secondly,the paper used simulation software of ANSYS finite element to set up simulation model of thermoelectric overload protection relays and researched temperature distribution of the relay under different current excitation.It employed simulation to analyze temperature distribution of thermoelectric overload relay under different temperature conditions and defined temperature of thermoelectric overload protection relay based on simulation results.Finally,the paper took STM32F103RBT6 microcomputer as core to design hardware circuits suitable for thermoelectric overload relay,which mainly include temperature acquisition circuit,data storage circuit,display circuit,implementation circuit etc.Debugging control systems by control releasing device can realize motor's overload protection and display real-time state parameters when motors run. |
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