Bridge crane power outage causes and how to deal with

overhead bridge crane in use for some reason or sometimes unexpected power outage situation, then due to inertia, the crane can not be stopped immediately, is likely to be damaged workpiece and the machine, causing the accident, therefore, occurred off the bridge crane electrical phenomenon should pay attention to timely troubleshooting, to return to normal.
A traveling crane causes power outage
Crane main contactor coil power is due mainly to the following aspects:
(A) the vibration generated when the work carts make Waterloo rail combined with strong, power supply problems, causing the main contactor main contacts and normally open auxiliary contact and disconnect the main contactor coil failure and self-locking cause power outages.
(2) Waterloo local poor contact, resulting in a certain overhead crane rail line to the instantaneous phase, if the missing phase which happens to be connected to the control line, it will make the main contactor coil power, self-lock failure, even due to inertia glide  bridge gantry crane  poor contact at the re-energized after the main contactor coil is also unable to pull, you must re-press the start button.
(3) lifting heavy vibrations generated when the main contactor is not strong, the main contact and normally open auxiliary contacts while disconnected due to vibration, the main contactor coil is self-locking and power failure.
(2) the processing overhead crane power outage
Bridge crane control lines from the three-phase 380V power supply through the switch QS access bridge crane, removed from the two-phase three-phase power control circuit as the power to overhead cranes KM main contactor coil supply, the control circuit sequentially string into the overcurrent relay normally closed contact KI, KI1, KI2, KI3, for each crane motor overload protection; series with zero starting protection contacts Q1, Q2, Q3 for zero starting protection; string into security switch SA for emergency stop in case of an accident; string into three limit switches SQ1, SQ2, SQ3 chain protection for cranes; button SB used  gantry crane  start, the two main contactor normally open auxiliary contact KM completion of the main contactor self-locking; following several groups and each limit position limit switch cam controller corresponding to two pairs of contacts with the work, completed bridge crane limit.