Avoiding Drawn Arcs Between Sliding Contacts of Commutators

Electro mechanic contacts are widely used in several appliances, because they are cheap, but also very robust, capable to withstand overvoltage and overcurrent surges. Especially they are necessary with commutators of universal electric motors for they are enabling commutation. These motors achieve high power per a unit of volume due to their high shaft speed, and they are produced at relatively low costs for a unit of power. So, they are economically very important for their numerous production, and they use sliding contacts for their operation. The sliding contacts are mechanical contacts and so electric arcs ignite between their contact members during commutation, and usually they are drawn arcs. Therefore it is very important to determine contact materials which avoid forming the electric arcs.