Synchro unit of twin deck cranes

More about synchro unit of deck cranes

The two cranes install on the platform can function independently. As a single crane or combine as a twin crane by interlocking the two units mechanically. Therefore winches in both cranes are install with synchro units. The unit is connect to an electronic panel which controls their operation through of electrically control valves.

The function of the synchronizing system, is to connect together rotary motion of the hydraulic motors in order to obtain:

• Same speed of both motors;
• Same angular position of both motors.

This is achieve by installing to the hydraulic motors a DC operated speed control devices which allow the slower rotating motor to run at its own speed and brake the quicker motor to the same speed. The braking effort is automatically apply to the motor which is leading the rotation at any given instant.

Synchronizing unit of twin cranes

The synchro unit provides pulsed signal, at power line frequency, which control the hydraulic motor speed by controlling the feed currents of the servo valve. A position signal error of the hydraulic motors can occur and is handle by the synchro unit which continually register the movement winches. So if the error angle exceeds a limit value and adjustable is out of range the electrically operate servo valves is interrupt, and the hydraulic motor cease.

The synchro unit comprises of a transmitter and control transformer. This continually register the position of the hydraulic motors and translate into a position error signal which is fed into the associated electronic circuit.

If the error angle between the two hydraulic motors exceeds a limit value adjustable within the range of approx 5 to 20 ° *degrees of synchro rotation the power supply to the speed unit is cut off and the hydraulic motor ceased.

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