Trivia. Little Wheel on the Gear

The Gene­va wheel is at the heart of every tap chang­er: It reg­u­lates the tap-change oper­a­tion by break­ing down a uni­form rota­tion into indi­vid­ual steps. This requires two ele­ments: the slots and the exter­nal con­tour. The dri­vers engage with the slots and turn the Gene­va wheel by a set angle. This is defined by the num­ber of slots: if, for exam­ple, the 360-degree rota­tion is divid­ed into sec­tions of 40 degrees, this pro­vides nine pos­si­ble steps. The round­ed areas on the out­er sides of the wheel limbs, also known as the lock­ing con­tour, pre­vent the wheel from con­tin­u­ing to rotate in an uncon­trolled man­ner in the rest phas­es.


The Gene­va wheel must work reli­ably for the entire life of the on-load tap-chang­er and must be absolute­ly wear-proof. That is why we design and pro­duce all metal­lic Gene­va wheels our­selves. Reinhausen’s largest Gene­va wheel has a diam­e­ter of over 81 cen­time­ters. It is fit­ted in the OILTAP® G. This one here mea­sures just 5.5 cen­time­ters and is found in the con­trol gear of the small­est tap chang­er in the world, the ECOTAP VPD.

In the ECOTAP VPD, the Gene­va wheel is not in oil, so the require­ments regard­ing cor­ro­sion resis­tance are high. That’s why we use a spe­cial brass alloy.

Find out more about the ECOTAP VPD