A qualified commutator can normally work under the temperature between -40ºC and 95ºC and relative humidity below 90%. And its outside surface is complete, no burr, the working surface is a smooth cylinder, the plastic part is cracked and defective.
Through Low-temperature test, High-temperature test(200ºC+5ºC, 300min) and temperature variation test, the shape of commutator will not be altered and loose. The plastic commutator shaft the hole center line, the change of the casing is not over 0.09mm, and the backlash of sheet is not over 0.015mm.
