The normal working temperature of jack oil pump is 10~50 ℃. If the oil temperature is too high, cooling measures shall be taken or the pump shall be stopped; If the oil temperature is too low, heating measures or low pressure operation shall be taken to increase the oil temperature. Before starting the motor, change the reversing valve to the middle half position. Jog several times to prevent the high-pressure pump from being emptied, and use it only after air is removed.

Jack is divided into mechanical jack and hydraulic jack, and the principle is different. In principle, the most basic principle that hydraulic transmission is based on is Pascal's law, that is, the pressure of liquid is consistent everywhere. In this way, in a balanced system, the pressure exerted on a smaller piston is smaller, while the pressure exerted on a larger piston is larger, so that the liquid can be kept still.