Makina opangira magetsi osatuluka masika (yomwe imatchedwanso "non-spring return" kapena "motorized damper actuator") ndi chipangizo chomwe chimagwiritsidwa ntchito m'makina a HVAC kuwongolera malo a dampers (mbale zowongolera mpweya) popanda makina omangira masika. Mosiyana ndi ma actuators a kasupe, omwe amadalira kasupe kuti abwererenso kumalo osasintha (mwachitsanzo, kutsekedwa) mphamvu ikatayika, oyendetsa omwe si a masika amakhala ndi malo awo omaliza mphamvu ikadulidwa.