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.