main component of the invention is the casing 21 responsible for providing protection against small dust particles or dirt casing 21 comprises a substantially u201c l u201d shaped body defining a cylindrical main portion and a leg portion radially extending in a plane perpendicular to the axis of said main portion said main portion having a first opening 25 at its upped end and said leg having a second elongated opening 23 at its distal end casing 21 is mounted to contact 18 by its a first opening 25 through a neck 22 in contact 18 and is mounted fixed to contact 16 and to conducting blade 15 through its elongated opening 23 contact 16 also has a highly conductive rivet 24 mounted on its conducting blade 15 in such a way that there is no sharp edge or burr it is important to point out that the casing 21 remains compressed when the motor is at rest and it goes back to its original position when the motor is operating fig2 shows the operation principle of fig1 and 3 it shows however the casing 21 in its open position with reference now to fig4 it follows the same principles of fig2 showing contacts 16 and 18 in their open position that is after the machine has reached its ideal speed to switch off auxiliary winding 2 the centrifugal set 120 displaces the actuating disk 10 together with the prop washer 13 the flexible conducting blade 17 and the contact 18 moving said contact 18 away from contact 16 and stretching casing 21 with reference to fig5 and 6 support base 14 has a casing opening 26 to receive casing 21 which allows great easiness in the assembly process where conducting blade 15 contact 16.