Different operating pressure of hydraulic mechanism. Take the CY3 produced by Beijing Switch Factory as an example. At 20℃, the rated cylinder pressure is 11.7±0.98MPa and 17.65MPa. When the temperature changes by 1℃, the pre-charge pressure changes by 0.045 MPa.
In Fig. 5, when the hydraulic pressure contact SP4 in the 14.72 MPa, trip loop is disconnected; when the hydraulic pressure contact SP5 in the 13.73 MPa, trip loop is disconnected, the trip is not allowed. Then the intermediate relay can be started with this contact.
When the pressure is below 15.72 MPa,3SP3 contact is closed, the oil pressure reduction signal; when the hydraulic pressure is below 16.72 MPa, the contact SP1, SP2 closes and starts the oil pump pressure. When the oil pressure rises to 18.63 MPa, the SP1, SP2 is disconnected and the oil pump stops the pressure.
When the pressure is below 9.8MPa or above 24.5, MPa, the pressure abnormal signal is sent by the contact PP1, PP2 of the pressure gauge, and the oil pump motor can start the starting circuit (not shown in the figure), to prevent the slow separation of the oil breaker when the oil pressure drops to zero.