Mnemonic. 1  V: vertebral artery. 2  I: internal thoracic artery. 3  T: thyrocervical trunk I: inferior thyroid artery.  C: costocervical artery S: superior intercostal 1  artery. D: dorsal scapular artery.
Aircraft Engine Governors Repairs, Overhaul and Refurbishing, overhaul services, exchanges and technical support for all major governor manufacturers including McCauley, Hartzell, MT-Propeller, Woodward, Hamilton Standard, Aero Technologies and Jihostroj.
Automatic transmissions use mainline, governor, and throttle pressure valves to control and lubricate the transmission. Some of these have been replaced or work together with electronic controls. Governor pressure increases with vehicle speed. Older transmissions had mechanical governors that consisted of springs, centrifugal weights, and a spool valve to control this pressure. Governor pressure causes a transmission to upshift and throttle pressure causes it to downshift. Todayâs transmissions use solenoids for shift timing. Throttle pressure indicates engine load. Some transmissions use a vacuum modulator or throttle linkage to control the throttle valve. Late model vehicles use electric solenoids to achieve the same results. Shift Valves: Transmissions change gears by moving shift valves. Governor pressure works on one end of the valve and throttle pressure aided by a spring works on the other.