Dielectric testing is a evaluation process performed by applying a voltage to an electrical component that exceeds its normal operating voltage. The purpose of the test is to determine if a componentâs insulation is adequate enough to protect the user from electric shock.d. The most common type of testing is the dielectric breakdown test. In this procedure, a high voltage electrical current is applied to the component. The dielectric tester monitors the amount of current leakage during the test to determine if the insulation has failed.
With the development of the new 8-speed automatic transmission by ZF, the focus is not on the number of speeds but rather on the minimization of fuel consumption. There are a number of innovations that contribute to this development.
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.