Set the magnification scale to the maximum magnification, slowly turn the handle and at the same time rotate the measuring dial so that the galvanometer pointer points to the center line. When the galvanometer pointer is near the center line, accelerate the generator handle to approximately 120 revolutions per minute. Rotate and adjust the measuring dial at the same time so that the pointer points to the center line.
1. The wiring of the instrument terminals must be correct.
2. Adjust the mechanical zero position of the galvanometer after placing the meter horizontally.
3. Set the “magnification switch” to maximum magnification. Gradually increase the crank speed up to 150 rpm. When the galvanometer pointer deviates in a certain direction, turn the dial so that the galvanometer pointer points to the “0” point. At this time, the magnification gear on the cadran corresponds to the measured resistance value.
4. If the dial reading is less than 1 and balance has not been achieved, you can adjust the magnification switch to a smaller magnification until balance is fully adjusted.
5. If you notice that the galvanometer pointer is shaking, you can change the crank speed to eliminate the shaking.
6. If the sensitivity of the instrument's galvanometer is too low, you can inject water or salt water around the probe to moisten it
Detailed information < /p>< p>When the sensitivity of the galvanometer is too high, the potential detection needle can be inserted shallowly into the ground. When the sensitivity of the galvanometer is not sufficient, water can be injected along the potential detection needle to moisten it. . When the ground interference signal is strong, the speedof the generator can be modified appropriately to achieve smooth playback.
When the distance between the ground electrode and the current detection pin is more than 40m, the potential detection pin can be inserted a few meters straight from the position median, and the measurement error is negligible. . When the distance between the ground electrode and the current detection pin is less than 40m, the potential detection pin should be inserted in the middle of the straight line. When measuring, the grounding body must be disconnected from the protected equipment.
Baidu Encyclopedia-Megger Floor Resistance Test
Baidu Encyclopedia-Floor Resistance Meter
How to use Megger
< p>The function of the electrician's megometer is to test the resistance of the line or equipment, or the resistance of the line to the ground. It can also test the resistance of the equipmentnt to the ground. The method of using the megometer is to first short circuit. circuit the megger leads and shake it gently. Half a circle, the watch hands will return to zero, then the standard open circuit of the megger will be opened. The needle on your 120 RPM speedometer should be pointing toward infinity. p>The purpose and use of the megger
How to use the electrician's megger:
Connect the E terminal of the megometer to ground reliably and connect terminal L to the line under test. Shake the oscillating watch generator handle clockwise from slow to fast for about 1 minute. Wait for the oscillating watch hand to stabilize and take a reading. At this time, the value indicated by the megohmmeter is the value of the insulation resistance of the tested line to ground, and the unit is megohms.
The megohmmeters usedby electricians are commonly used in three types: 500V, 1000V, and 2500V, depending on the voltage they are measuring. existThere is no special timing. If the operating voltage of the equipment is 500 V and below, use a 500 V megger to measure it. If you choose a high voltage megger, it may damage the insulation of the equipment under test. is greater than 500 V and less than 3000 V, use a 1000 V megohmmeter. For measurements, use a megger of 2500 V to 3000 V and above.
Precautions for use
1. When measuring the insulation resistance of the equipment, the power supply to the equipment should first be turned off. Equipment containing inductors and capacitors (such as capacitors, transformers, motors and cable lines) should be discharged first. Off-duty personnel must request the appropriate work ticketslaying before being able to work.
2. The oscillator must be placed horizontally. Before wiring, you need to shake the oscillator and observe whether the pointer is on ∞. Then short-circuit terminals L and E and slowly shake the watch. The needle should be at zero. After open circuit and short circuit tests, the megger is confirmed to be intact before measurement can be made.
3. The lead wire of the megger should be a multi-stranded soft wire and the two wires should not be twisted together to avoid inaccurate measurement data.
4. After the megger measurement is completed, the measured object should be unloaded immediately. Do not touch the measuring part of the measured object or disassemble it with your hands until the megger stops rotating and the measurement is completed. the object is not discharged to avoid electric shock.
5. The surface of the object to be measured must be wiped cleaned and there should be no dirt (such as paint, etc.) to avoid inaccurate measurement data.
Purpose: In order to avoid accidents, this is a megohm level resistance meter used to measure the insulation resistance of various electrical equipment. The megger is convenient and practical for measuring insulation. resistance.
Instructions for use:
1. Before measurement, the power supply to the electrical apparatus and circuit under test should be cut off, and the relevant components should be temporarily grounded and discharged. ensure the safety of people and the megger and the measurement results are accurate.
2. The wiring must be correct when measuring. The megger has three terminals (L, E, G). When measuring the loop resistance to ground, the L end is connected to the exposed loop conductor and the E end is connected to the ground wire or metal shell.that when measuring the insulation resistance of the loop, the first and ; the last ends of the loop are connected to L and E respectively; cable insulation is measured when measuring resistance, in order to prevent leakage current on the cable surface from affecting the measurement accuracy, the cable shielding layer should be connected to the terminal G.
3. The flexible measuring wire coming from the megger terminal should be well insulated and a proper distance should be maintained between the two wires and between the wire and the ground to avoid affecting the measurement accuracy.
4. When shaking the megger, do not touch the megger terminals and the circuit under test with your hands to avoid electric shock.
5. After shaking the megger, do not short the terminals to avoid damage.
6. Don't shake the megger for too long.
Detailed information:
Remarks
1. insulation during lightning strikes or near high voltage equipmentInsulation resistance can only be measured when the device is not powered and there is no induced electricity.
2. During the shake test, no one may work on the equipment under test.
3. When measuring the insulation resistance of the equipment, the power supply to the equipment should first be turned off. Equipment containing inductors and capacitors (such as capacitors, transformers, motors and cable lines) should be discharged first. Off-duty personnel must request corresponding work tickets before they can work.
4. The oscillator must be placed horizontally. Before wiring, you need to shake the oscillator and observe whether the pointer is at "∞". Then short-circuit terminals L and E and slowly shake the watch. The needlee must be zero. After open circuit and short circuit tests, the megger is confirmed to be intact before measurement can be made.
5. The leads of the megger should be multi-stranded flexible wires, and the two wires should not be twisted together to avoid inaccurate measurement data.
Reference documents:
Baidu Encyclopedia - Shake Table