These gears are not used to transmit torque but to transmit position information. Especially the synchronization required for automation is done with trigger belts and pulleys. Since these gears do not transmit torque, their tooth depth is extremely small.
These gears are used together with trigger belts. The English term for these belts is timing belts and the most important thing in this duo is that there is not the slightest slippage between the belt and the pulley. In this system the trigger gear speed can go up to 10,000 rpm. Since they are not expected to transmit torque, the amount of belt tension is kept very low to ensure a long service life. However, since it is very important to ensure that the teeth on the belt are in constant contact with the teeth on the pulley, an idler pulley is used on the loose side if necessary.