Effect of wheel speed on the tracking time in a rotating wheel-spray tracking test

A low speed rotating wheel spray test procedure for insulation is described and typical results are presented on a number of low tracking resistance polymers. It is found that the time to tracking is a monotonically increasing function of the wheel speed at low speeds of up to 2.0 RPM. This reverse behavior of what normally occurs at high wheel speeds is explained in terms of residence times of the specimen in the water spray and in the air as a function of the speed.<
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