Hydraulic turning gear for gas turbine

The hydraulic barring gear comprises a hydraulic motor, a barring box body is fixedly installed on one side of the hydraulic motor through bolts, a hydraulic cylinder is installed on the barring box body, a piston rod of the hydraulic cylinder is movably inserted into the barring box body, the piston rod of the hydraulic cylinder is fixedly connected with a gear swing frame, and a spring is sleeved on the piston rod of the hydraulic cylinder. In the using process, when static state is needed, the turning gear is started, a two-position three-way electromagnetic valve of the hydraulic cylinder is controlled to be powered on, high-pressure oil enters from a lower cavity of the hydraulic cylinder, and under driving of hydraulic pressure, a piston rod of the hydraulic cylinder moves upwards to overcome spring force of a spring, so that the hydraulic cylinder is driven to be in the static state. When the gas turbine is started, the idle gear is driven by the gas turbine, so that the safety is ensured, and the cont