Discussion on the causes of power failure of gantry crane used by rail shiploader manufacturers

When we use the gantry crane, for some reasons, we often have the problem of power failure. At this time, because of the inertia force, the machine can't stop working immediately, so it is very easy to damage the product workpiece or machine tool. In serious cases, it may also lead to other accidents. I have analyzed the following reasons for the power failure of the machine and equipment and the corresponding solutions. You can also have a serious understanding.

Reason:

1. The vibration during the operation of the crane makes the combination of the sliding iron and the guide rail unstable, and the power supply has problems, which leads to the main contact and the normally open auxiliary contact of the main contactor break at the same time, and the coil self-locking device of the main contactor is invalid, resulting in power failure.

2. The loose part of the slide iron causes the instantaneous phase loss when the crane reaches a certain section of the slide rail. If the missing phase happens to be connected to the control line, the coil of the main contactor will be powered off and the self-locking device will be invalid. Even if the machine and equipment are powered on again after sliding over the loose part due to inertial force, the coil of the main contactor will not be able to automatically pull in. Be sure to press the start button again.

3. When lifting heavy objects, the vibration makes the main contactor pull in unstable, the main contact and normally open auxiliary contact break at the same time due to vibration, and the coil self-locking device of the main contactor is invalid and the power is cut off.

The specific measures are as follows

1. The crane control line is connected from the three-phase 380V power supply through the switch QS. Two phases are taken from the three-phase power supply as the power supply of the control line to supply power to the main contactor coil km. The over-current relay normally closed contacts Ki, Ki1, ki2 and KI3 are connected in series in the control line to protect each motor from over-voltage.

2. Connect the zero starting protection contacts Q1, Q2 and Q3 in series for zero starting protection.

3. The safety protection switch SA is connected in series for emergency braking in case of accident.

4. Three limit switches SQ1, SQ2 and SQ3 are connected in series for protection.

5. Button sb is used for starting, and two normally open auxiliary contacts km of main contactor are used for self-locking device of main contactor.

6. The next several groups of limit switches and the corresponding two pairs of contacts of each cam controller work together to limit the crane.

When we use the gantry crane in our daily life, if we find that it has power failure, we should attach great importance to it, timely remove the fault, and make it return to normal, so as to ensure that the machine can give full play to the ideal practical effect.