A facility for electrical contact resistance measurement

A test facility was developed for directly measuring the electrical contact resistance of switch gear contacts of real sizes under different environmental conditions and contact pressures. It can measure contact resistance to an order of one-tenth of a μΩ. It sources a constant current in the order of mA and hence avoids initial arcing across contacts. Experiments were conducted on brass–brass samples with different contact pressures and the results are in agreement with published theoretical calculations.