Valves electrohydraulic actuators

Some lifts use electrohydraulic actuators to hft and fold, with valves and gravity used to lower the lift. Crane lifts may swing out from a post at the front or rear of the side door. Interlocking mechanisms are available with some lifts to prevent the lift from being operated while the door is closed. The Society of Automotive Engineers (SAE) has developed guidelines for the testing of wheelchair lift devices for entry and exit from a personal vehicle. The standards are intended to set an acceptable level of reliability and performance for van hfts. 

The flow of main steam entering the high-pressure turbine is controlled by four control valves. The turbine control valves are adjusted automatically by electrohydraulic servo actuators. These actuators control the turbine speed when it is starting up, and for load control after the turbine-generator unit is synchronised. In series with each control valve is a stop valve, whose function is to shut off and isolate the steam flow to the turbine when required. 

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