During the entire process used to start the electric motors, it must be switched on in the star configuration until it can reach an approximate speed of the speed regime, in case this connection is undone and the connection in triangle . Therefore, the switching of the connection in the starting process is accompanied by an increase of current, in this way, so that the advantages of its reduction disappear, if the switching is anticipated with respect to the ideal point. https://www.mrosupply.com/couplings-collars/elastomer-couplings/478707_7300090hsu_rexnord/ In this way, an engine will only be able to start by means of a star-delta key when its torque on the star connection is greater than the torque of the axle load.
Because of the low starting torque to which the engine is subjected, the star-triangle wrenches are most appropriately employed on starter motors. In industrial electrical installations, star-delta type switches can be used as a way to soften the starting effects of electric motors. The activation of an electric motor carried out by means of star-delta switches is only possible if it has six accessible terminals and also has a nominal double voltage.