列車主電流監測記錄裝置由主電路電流傳感器和監控主機兩部分組成。其中電流傳感器采用LEM的LT 4000-S型，量程范圍可達6000A，額定有效值為4000A，原次邊電流變比為1:5000。監控主機由采樣電路、CPU、大容量Flash、顯示、報警和電源等模塊電路組成，主要負責對經過電流傳感器變換之后的列車主電流進行采集、判斷和記錄，同時提供必要的數據上傳、顯示和報警功能。      電流傳感器的輸出信號進入監控主機內，經采樣濾波隔離測量后，監控主機對超過正常閥值的數據進行觸發操作。       

    本裝置在正常工作時，實時采樣監測主電流電流變化，并將采集到的數據緩存到內部存儲器中。一旦發現主電流值超過所設置的閾值（峰值超過設定值保持一定時間或者是電流變化超過設定值，這些參數都可以通過上位機進行修改），系統會將該時刻前后特定時間段內的持續測量數據記錄下來，并將緩存中的數據轉存到大容量的Flash中，以供日常維護人員下載后在上位機軟件進行連續波形顯示和分析。當電流變化達到報警閾值時，系統會觸發警報，提醒列車工作人員進行檢修。

        The main current monitoring and recording device of the train is composed of two parts, the main circuit current sensor and the monitor host. Current sensor use the LEM of LT 4000-S, the range can be 6000A and rated effective value is 4000A, the original secondary side current ratio is 1:5000. Monitoring host is composed of the sampling circuit, CPU, Flash, display, alarm and power supply module circuit, the main responsibility is to collect, judge and record the train main current after the transformation of the current sensor, and provide the necessary data upload, display and alarm. 

        The output signal of the current sensor is transmitted into the monitoring host, when after sampling filter isolation measure, the monitor host will do triggering action to the over normal threshold data. 

       When the device is in normal operation, it monitors the change of main current in real time and caches the collected data into the internal memory. Once the main current value exceeds the set threshold(the peak value is over the setting value and maintains for a certain period of time or the change of the current exceeds the set value, and these parameters can be modified by the host computer), the system will record the continuous measurement data in a specific time period and cache the data stored in the buffer to the large capacity Flash, in order to provide a continuous wave display and analysis of the upper computer software after downloading. When the current change comes to the alarm threshold, the system will trigger the alarm to remind the train staff to carry out inspection.