Development of a Prediction Method for Temperature Rise in Connector Terminals under Steady Current Flow

摘要

This paper describes a prediction method for temperature rise in a pair of wired plug-and-receptacle electrical connector terminals under given constant current flow using three-dimensional structural, electrical, and thermal finite element methods (FEMs). To predict temperature rise in terminals, we must estimate (1) Joule's heat generation under given current flow, (2) heat conduction in terminals and wires, and (3) heat dispersion, i.e., convection and radiation from the outer surface of terminals and wires into the atmosphere. Electrical resistance, which causes Joule's heat generation, consists of three components; (1) conductive resistance in terminals and wire conductors, (2) contact resistance between terminals, and (3) connection resistance between terminal and wire conductor, for example, by crimping. The last two components have been difficult to calculate theoretically up to the present and this has been one difficulty in developing a temperature rise prediction method for terminals. However, for contact resistance between terminals, we have developed an estimation method incorporating a combination of terminal insertion simulation using structural FEM and theoretical calculation of contact resistance for a simple contact model. Another difficulty in computing temperature rise in wired terminals using FEMs is that both terminals and wires must be modeled, i.e., divided into small finite elements. However, the complete modeling of terminals and wires becomes too time-consuming for computer calculation, so we have developed an alternative method combining thermal network model analysis for a single wire and electrical and thermal FEMs for terminals without wires. Applying this method to the prediction of temperature rise under current flow up to 150A for type 9.5 terminals with 15mm~2 wires, the predicted terminal values have been satisfactory agreed to experimentally obtained values.