The elevator is broken for some reason, causing the loop that should be connected to be unreachable.
The cause of the open circuit is mainly due to the loosening of the lead wire of the electrical component;
Weld welding or poor contact as a connection point in the circuit;
The contact of the relay or contactor is burned by the arc; the surface of the contact is made of an oxide layer;
When the reed of the contact is turned on or off, the arc is heated, and the elastic force is lost after cooling, which causes the contact pressure of the contact to be insufficient; when the relay or the contactor is closed or disconnected, the contact of the contact is poor due to the jitter.
