The hydraulic system is an important auxiliary equipment of the hoist and the fundamental guarantee for the safe operation of the mine hoist. The operation performance and safety protection of its hydraulic station directly affect the equipment and personal safety, so it is urgent to improve the electrical protection design of the hydraulic station of the hoist.
Protection of Hydraulic Pump Motor Abnormal Trip and Stop
The main reasons for the trip of the hydraulic pump motor are: human misoperation of the hydraulic pump stop button, overcurrent of the motor power supply and power failure of the motor contactor, the safety circuit is closed when the hydraulic pump motor trips, and the working brake solenoid valve is still energized. The power source provided disappears, the oil returns to the fuel tank through the normal working oil circuit, the brake oil pressure drops to zero instantly, the braking effect is equivalent to the first-level braking, and the hoist is very easy to slide the rope. After that, because the full braking force is applied to the hoist, the overcurrent fault safety circuit of the hoisting motor is automatically disconnected, causing damage to the hoist. The occurrence of such a situation has a greater impact on the hoist, and prevention should be the main priority. The electronic control system program can increase the safety protection of the motor from abnormal tripping.
(1) The electronic control system controls the electrified logic of the solenoid valve, switches the working oil circuit of the hydraulic station to the brake oil circuit, cuts off the unloading oil circuit, and the electrified and pressure-retaining solenoid valve is electrified with a delay of 0.5 s to maintain a certain amount of brake oil. pressure and wait for the safety circuit disconnection command.
(2) Send an emergency stop fault signal to the main control system, disconnect the main control safety circuit, and power off the hoist motor.
(3) After receiving the disconnection command of the main control safety circuit, the hydraulic station performs normal constant deceleration or secondary braking.
The results show that adding electrical protection can prevent the hydraulic pressure of the brake from dropping to zero instantaneously and reduce the impact on the hoist. This is good news for hydraulic station manufacturers and customers.