Stray Current Tester
Darui Electric recommends:
I. Purpose
FZY-3 Mine Stray Current Tester is a portable rectifier instrument with high sensitivity and multi-range protection circuit. Its features are: wide measurement range, with a total of twenty ranges, capable of measuring AC/DC stray voltage and stray current respectively, no internal power supply needed, safe and reliable. It is suitable for testing the current and voltage generated by steel 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
Instrument measurement range and accuracy class
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Measurement Range
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Measurement Accuracy
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Remarks
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Current Range
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0-50mA-250mA
-1A-5A-10A
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AC ±5%
DC ±2.5%
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Before use, the pointer must be adjusted
to zero position, i.e., zero adjustment
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Voltage Range
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0-0.2V-1V
-4V-20V-40V
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III. Usage Methods and Precautions
1. 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., steel rail, water pipe, cable sheath, 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 determine test points temporarily as needed. Set the range switch to the appropriate position, and the meter reading, after conversion, gives the corresponding current value.
3. During measurement, the hard alloy tip of the measuring probe should have good contact with the object under test, and the instrument should be placed horizontally to ensure accurate readings.
4. When AC stray current cannot be 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 maximum range, then gradually decrease until an appropriate measuring range is found.
7. When the measured current exceeds 5A, the instrument should only be used for short-time measurements; when the measured current exceeds 10A, the instrument should only be used for instantaneous measurements, to avoid large currents burning out components and the meter.
8. When measuring DC stray current, if the meter pointer deflects in the reverse direction, swap the test leads.
9. When the instrument is not in use, set it to the "Off" position.
Note: The above information and technical parameters are compiled and released by Yangzhou Darui Electric Co., Ltd.
