I. Purpose of Mine Stray Current TesterThe mine stray current tester is a portable rectifier instrument with high sensitivity and multi-range protection circuit. Its characteristics are: wide measurement range, with a total of twenty ranges, capable of measuring AC/DC stray voltage and stray current separately, no power supply needed, safe and reliable. It is suitable for testing the current and voltage generated by rails, water pipes, cables, etc. in coal mines, preventing premature detonation of electric detonators and other combustion and explosion accidents caused by stray current discharge, minimizing fire sources in mines.


II. Performance of Mine Stray Current Tester: Measurement Range and Accuracy Class

Measurement Range
Measurement Accuracy
Remarks
　　
Current Range
0-50mA-250mA
-1A-5A-10A
AC ±5% DC ±2.5%
Before use, the pointer must be set to zero position, i.e., zero adjustment.
Voltage Range
0-0.2V-1V
-4V-20V-40V
　　
　　


III. Usage Methods and Precautions for Mine Stray Current Tester1. Before measurement, screw the test lead connectors onto the two binding posts respectively, and adjust the meter pointer to the zero scale line. 2. Place the test leads connected to the binding posts on the two points to be measured (e.g., rails, water pipes, cable sheaths, coal, ground, etc.). The two test points should be on different conductors, with a distance of about 2 meters. Normally, measure every 50-100 meters, or temporarily determine test points as needed. Set the selector switch to the appropriate range, and the meter reading, after conversion, gives the corresponding current value. 3. During measurement, ensure the hard alloy tip of the measuring probe makes good contact with the object under test, and the instrument should be placed horizontally to ensure accurate readings. 4. If no AC stray current is measured at a location, also test for DC stray current, and vice versa. 5. When measuring stray voltage values, the corresponding ranges are: 50mA corresponds to 0.2V, 250mA to 1V, 1A to 4V, 5A to 20V, 10A to 40V. (i.e., current value multiplied by 4 gives the voltage value) 6. When the magnitude of stray current is unknown, first set to the highest range, then gradually decrease until an appropriate measuring range is found. 7. When the measured current exceeds 5A, only short-time measurements are allowed; when it exceeds 10A, only instantaneous measurements are allowed, to prevent large currents from burning out components and the meter. 8. When measuring DC stray current, if the pointer deflects in the reverse direction, swap the test leads. 9. When the instrument is not in use, set it to the "Off" position.


IV. Product Completeness of Mine Stray Current Tester1. Main unit: one unit 2. Test leads: one pair 3. Product manual: one copy 4. Product certificate of conformity: one copy