L46A1 Mast Section The tower hoist's electrical protection.
The electrical control system of tower crane should be equipped with the necessary electrical protection measures to protect the safety of electrical equipment and personnel. The main electrical protection measures of tower crane are: main isolation switch, short-circuit protection and voltage loss protection of total power supply, zero-position protection, overload protection of motor, magnetic loss protection and speeding protection, emergency power off switch, limiting position protection and stroke protection, interlocking protection of passage gate and ground protection. And ...
1 Main isolation switch
Maintenance inspections of electrical equipment should normally be carried out in the event of a power failure. Therefore, there should be isolation switches or other isolation measures between electrical equipment and the power grid. When the isolation switch is disconnected, it must maintain a valid disconnect distance and a visible disconnect point so that the maintenance staff can intuitively confirm that the total power supply circuit has been disconnected.
When the air switch and the iron shell switch are disconnected, they are sometimes inconsistent with the state, there is no obvious disconnect point, and they can not be used as isolation switches. Can only be used as a load switch.
Short circuit protection of total power supply
When the electrical equipment on the crane is damaged by insulation, the short-circuit protection device of the total power supply should move quickly to cut off the faulty power supply. The short circuit protection of the total power supply requires that each phase must be set up to ensure that the fuse fuse or automatic circuit breaker action occurs when any two or any other short circuits occur.
When a crane is powered by a cable or a set of sliding lines for a crane, the crane may not be equipped with a short circuit protection of the total power supply if the total power supply switch has been installed on the ground and has a short circuit protection function. If multiple cranes share a group of sliding wires and set up a total power switch on the ground, each crane should be required to set up a fuse or circuit breaker separately as a short-circuit protection device for the total power supply.
3 Pressure loss protection of total power supply
The loss of voltage protection of the total power supply means that the total power supply loop can be automatically disconnected after the power supply is interrupted; When power supply is restored, the total power loop can not be connected by itself without manual operation. Generally, the button that can be automatically reset is strung into the voltage loss protection of the total power supply contactor coil or the voltage loss release coil loop of the automatic circuit breaker.
If the total power supply has no loss of voltage protection and the power supply is resumed after the power supply is interrupted, the total power supply can be connected without manual operation. In this regard, sometimes the operator did not find that it was mistaken for the total power supply or no power, and intentionally or unintentionally touched the controller, causing errors and accidents.
