Protector for three-phase motor of alternating-current or direct-current electric locomotive

Abstract

The invention provides a protector for a three-phase motor of an alternating-current or direct-current electric locomotive. The protector comprises a current transformer, a KM contactor, a data processing chip, a delay and a switching signal collector, wherein the current transformer and the KM contactor are connected to a subcircuit of the three-phase motor in series, the current transformer, the relay and the switching signal collector are all electrically connected with the data processing chip, the normally-closed node of the relay with the input end electrically connected with a control switch is electrically connected with the KM contactor, the normally-open node of the relay is electrically connected with a fault signal output circuit, and the witching signal collector is electrically connected with the control switch. A novel power electronic device is adopted in design, the sensitivity is high, defects of traditional tripping switch protection are overcome, and the protector can be suitable for various environments.

Description

Technical field [0001] The invention relates to the field of locomotive safety, in particular to a three-phase motor protector for AC-DC electric locomotives. Background technique [0002] At present, the locomotive depot of the railway bureau generally uses the automatic trip switch to protect the auxiliary three-phase motor of the locomotive (hereinafter referred to as the auxiliary engine). Such as 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 normally closed when there is no current in the auxiliary branch circuit. When the driver presses After the control switch is turned on, the 110V power supply is turned on, 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 limit val...

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. The user 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 severe 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

Images