A three-phase motor protector for AC/DC electric locomotive

Abstract

The present invention proposes a three-phase motor protector for an AC / DC electric locomotive, which includes a current transformer and a KM contactor connected in series on the branch road of the three-phase motor, and also includes a data processing chip, a relay and a switch signal collector; the current The transformer, relay and switch signal collector are all electrically connected to the data processing chip; the normally closed node of the relay electrically connected to the control switch is electrically connected to the KM contactor, and its normally open node is electrically connected to the fault signal output circuit; The switch signal collector is electrically connected with the control switch. The invention is designed with new power electronic devices, has high sensitivity, overcomes the shortcomings of previous tripping switch protection, and can adapt to various environments.

Description

technical field [0001] The invention relates to the field of locomotive safety, in particular to a three-phase motor protector for an AC / DC electric locomotive. Background technique [0002] At present, the locomotive depot of the railway bureau generally uses an automatic trip switch to protect the auxiliary three-phase motor of the locomotive (hereinafter referred to as the auxiliary machine). like figure 1 As shown, the trip switch is equivalent to the "fuse" of the motor, which is connected in series between the KM contactor and the three-phase power supply; the trip switch is in the normally closed state when there is no current in the branch of the auxiliary machine. After the control switch is lowered, the 110V power supply is connected, so that the KM contactor is closed, and the auxiliary three-phase motor starts to work. During the operation of the three-phase motor, when the current of the auxiliary branch circuit is too large and the temperature rises to the li...

AI Technical Summary

Problems solved by technology

[0004] ①. The accuracy of overheating detection is not high. In some cases, the auxiliary machine has burned out and the tripping has not yet fallen off;

[0005] ②, slow response, unable to reflect the changing trend of current in real time, prone to misoperation;

[0006] ③. The error range is large, and the protection parameters cannot be adjusted by themselves. Users can only choose a trip switch with a fixed model and parameters, which is not flexible enough;

[0007] ④. It is bulky, bulky and has no information function, which brings inconvenience to users for installation, use and maintenance

[0008] ⑤. It is prone to sticking phenomenon. Once the tripping is bonded, it will not have any protective effect on the auxiliary machine. In the case of serious overcurrent of the auxiliary machine, if it cannot automatically fall off, it will easily cause the auxiliary machine to burn out;

[0009] ⑥. The trip switch cannot be closed automatically when it falls off. It needs to be manually reset to close, which is very troublesome.

[0010] In addition, in some sections of our country with a long history, high utilization rate of the power grid and relatively tight transport capacity, there are often situations where the voltage is low but vehicles need to be forced to pass through the area. At this time, in order to prevent the trip switch from triggering the protection automatic When the power is cut off, the maintenance personnel can only temporarily stop to replace the trip switch with a higher rated current, which is time-consuming and laborious, which seriously affects the driving efficiency

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