The method is as follows:
1. Before use, the megger should be placed away from the magnetic field and placed on a horizontal surface without being tilted too much.
2. Attach the megger measuring leads to the two terminals of the megger. The two measuring leads are both positive and negative, then tighten the screws.
3. Attach one measuring lead to the motor winding and the other measuring lead to tighten the motor housing.
4. At this time, start rotating the indicator handle, approximately 120 revolutions per minute, and wait for the indicator to stabilize, then take the reading.
5. Each pair of motor windings must be measured using this method. If a group does not meet the standard, the motor cannot be used.
Precautions for use:
1. It cannot be used with electricity. Electricity must be tested before measurement. Insulation should be measured where electricity istested.
2. After measurement, large capacity equipment should be unloaded.
3. Not all equipment, such as frequency converters, can be measured when the power is turned off.
4. The meter wires cannot be twisted together, but must be separated.
5. During the shake test, no one may work on the equipment under test.
6. It is prohibited to measure insulation resistance during lightning or near high voltage equipment. It can only be measured when the equipment is not charged and there is no induced electricity.
7. It is strictly forbidden to touch the megger with hands until it stops rotating or before the device under test is discharged. When removing the wires, do not touch the metal parts of the cables.
How to use a megger to measure grounding
A meggeris a megger with a manual generator inside. The generator voltage is very high. After rectification, to charge the high voltage capacitor inside, it uses the high voltage capacitor as a power supply. If the voltage is insufficient, it is powered manually and the generator voltage is higher than 200V.
The high DC voltage generated by the internal battery as a power source through DC/DC conversion flows from pole E through the test product to pole L, thereby generating a current from pole E to pole L, which undergoes I/V conversion. After the operation is completed by the divider, the resistance value d The measured insulation is directly displayed on the LCD screen.
Detailed information:
Once the reading is complete, discharge the device under test. The discharge method involves removing the ground wire used when measuring from the megger and shorting it to the device under test (no discharging the megger).
Question 1: How do I use a megger to test if a line is grounded? A megger, also known as a megohmmeter, is an instrument used to measure insulation resistance and high value resistance. of the equipment tested. It consists of a manual generator, a meter and three terminals (i.e. L: end of line, E: end ofmass, G: shield end).
Megger, also known as megger, is used to test the insulation condition of electrical circuits or equipment. The usage method and precautions are as follows:
1. First, select a megometer suitable for the voltage level of the component under test. For electrical lines or equipment rated 500 V and below, a 500 V or 1000 V megometer should be used. For electrical lines or equipment above 500 V, a 1000 V or 2500 V megger should be used.
2. When testing the insulation of high voltage equipment with a megger, two people should do it.
3. Before measurement, the power supply of the circuit or electrical equipment under test must be completely disconnected, that is, it is not allowed to measure resistance insulation when the device is powered. And make sure no one workse on the wiring or electrical equipment before continuing.
4. The meter wire used by the megger must be an insulated wire and it is not suitable to use a double stranded insulated wire. The ends of the meter wires must have insulating jackets; L" of the megger. Ground terminal "E" should be connected to the measured phase of the equipment. Ground terminal "E" should be connected to the shell of the equipment and the unmeasured phase of the equipment. The shield terminal "G" should be connected to the protection ring or cable insulation sheath to reduce the impact of leakage current on the insulation surface Error caused by measurement.
5. The megger should be checked for an open circuit before measuring When the “L” end and “E” end of the megger are discharged, the shaker pointer should point to “∞. » when the “L” end and “E” end of the megger are short-circuited, is shaken.the pointer should point to "0". This indicates that the megger is working well and can be used.
6. The circuit or electrical equipment under test must be grounded and discharged before testing. When testing a line, you must obtain permission from the other party before continuing.
7. When measuring, shake the scale handle at a uniform speed of 120 rpm; take the reading after maintaining a steady speed for 1 minute to avoid the influence of current draw.
8. During the test, both hands are not allowed to touch both wires at the same time.
9. After the test is completed, the stitches should be removed first, and then stop shaking the watch. This helps prevent electrical equipment from charging the megger and damaging it.
10. During a lightning strike, it is strictly forbidden to test the insulation of the line.
Set of questions:
The enginesrs of 380 volts typically use 500 volt or 1000 volt meggers.
The megger relies on its own power output to generate current to measure resistance. The measured object should not be loaded and should be unloaded before testing, otherwise the test results will be affected.
What is the insulation resistance standard for measuring a load with a megger?
Generally, if the measurement exceeds 1 MΩ, it meets the insulation requirements of low-voltage equipment.
The current standard seems to be 380V 0.5M or more. Determined as a function of voltage, it can be explained by Ohm's law. This means that the voltage on the wire divided by the resistance of the insulation equals the current outside the wire. Just make sure it doesn't feel dangerous to the touch. About 1000v=1M How to use a meggerMeasure the motor resistance to determine the quality of the motor.
I will tell you how to determine the quality of the engine. After disassembling the connection parts, first use a multimeter to measure the DC resistance of the motor. the three-phase winding.
In fact, the winding resistance is very low. You can hardly determine the size with an ordinary meter. Unless it's a very small engine, you can just check to see if it's there. It's continuity. If the three-phase windings are all connected, use the first part of the megger. One wire is connected to the motor shell and the other wire is used to measure whether the resistance of the three-phase windings. the earth is normal. The minimum resistance value should not be less than 0.5 megohm3. If the resistance of the three-phase windings to ground is normal, the final step is to measure the insulation between the phases. you can randomly connect a lead from the megger to the terminal of a winding ofphase and connect the other wire to the other two terminals respectively. After measurement, connect them separately. the wires are interchanged to measure the windings of the other two phases. The inter-phase measurement process only requires measuring the upper or lower three terminals, and the resistance should not be less than 0.5 megohms.
Attach one of the two oscillator test leads to the junction box terminal and attach the other to the case. Shake the oscillator handle evenly. The reading obtained is the insulation resistance of the. grounded motor. Generally, it is considered qualified if it is around 200K~2M.
Attach the two oscillator test leads to the terminals of the different phases in the junction box and shake the oscillator handle evenly. The reading obtained is the insulation resistance between the motor phases. Generally, it is qualified if it is greater than 100K
Question 2: How to use the grounding megometer Friends, 1. The testing method of the ZZC29B-2 type megometer is as follows:
(1) When measuring the earth resistance at the two E-E terminals, short circuit it with a chrome copper plate and connect it to the 5m long pure copper wire supplied with the meter. The end of the wire is connected to the ground test point to be measured. When measuring the shield resistance, loosen the chrome copper plate, connect one terminal E to the ground body and the other terminal E to the shield.
(2) The P pillar is connected to the 20m pure copper wire supplied with the meter, and the other end of the wire is connected to the pin.
(3) The C pillar is connected to the 40m pure copper wire supplied with the meter, and the other end of the wire is connected to pin 2.
2 ? Technical requirements for setting up the earth resistance tester
(1) Lhe earth resistance tester should be placed 1-3m away from the test point and the placement should be stable. and easy to use.
(2) The terminals of each terminal must be in good contact and firmly connected.
(3) The two grounding pins should be placed at a distance of 20m and 40m respectively from the grounding body to be measured; if the two pins are connected by a straight line, the grounding body to be measured; should basically be at It's a straight line.
(4) Other wires should not be used to replace the 5 m, 20 m or 40 m long pure copper wires supplied with the instrument.
(5) If the earth resistance tester is used as the center of the circle, the angle between the two pins and the tester should not be less than 120°, let alone the same.Parameters orientation.
(6) The ground where the two pins are fixed must be solid and cannot be put in the mud, the embankment, next to tree roots, grass, etc.
(7) The soil resistance test can only be carried out after 7 consecutive sunny days after rain.
(8) The grounding body to be tested must first be derusted to ensure a reliable electrical connection.
3? Working Principles of Earth Resistance Tester
(1) Start measuring the earth resistance value only after the tester parameters meet the specifications.
(2) Before measurement, the earth resistance adjustment knob should be turned to the maximum speed, which is x10 speed, and the earth resistance value adjustment knob should be placed on the 6 ~ 7Ω position.
(3) Turn the handle slowly. If the galvanometer pointer deviates quickly to the right from the 0 balance point in the middle, it means that the original range selection is too large. the range at x1, such as The directionThe deviation is as before, and the speed selection can be turned to speed x0?1.
(4) After selection in step (3), slowly turn the handle. If the galvanometer pointer moves to the right from the balance point 0, it means that the ground resistance value is still too large. . While slowly turning the handle, the floor resistance knob should be turned slowly clockwise. When the galvanometer pointer returns to 0, gradually increase the handle speed until the handle speed reaches 120 rpm. the earth resistance
is multiplied by the gearing. The bit multiple is the measured earth resistance value of the earthing body. If the galvanometer pointer slowly deviates to the left, it means that the resistance value of the earth resistance button is lower than the actual earth resistance value. YOUcan slowly turn it counterclockwise to increase the resistance indication value of the meter.
(5) If the galvanometer needle jumps irregularly when the handle is turned slowly, it means that the ground on the ground where the two grounding pins are fixed is not dense or there is a bad contact point. at one of the joints, in this case recheck two grounded pins or each connector.
(6) When measuring the soil resistance of a static pressure pile with a soil resistance measuring instrument, it is normal for the galvanometer needle to swing slightly toward the left and right at 0 o'clock.
(7) When the pointer of the galvanometer slowly moves to the 0 balance point, the handle of the instrument generator can be accelerated. The rated speed of the handle is 120 rpm. It is strictly forbidden to accelerater the rotation of the handle when the galvanometer needle still deviates strongly.
(8) After use, the resistance value of the measuring instrument should be placed in the maximum position, which is the x10 position. Lay out the three test leads supplied with the instrument, clean the dirt on the two pins, and put them in a bag for storage.
2. The ZC29B test method is as follows:
(1) When measuring the earth resistance at the two terminals E-E, use a chrome-plated copper plate for the short circuit and connect it to the 5m long pure copper wire, the other end of the wire is connected to the grounding test point to be tested. When measuring the shield resistance, loosen the chrome copper plate, connect one terminal E to the ground body and the other terminal E to the shield.
(2) The P column is connected to the one supplied with the instrument. 20 m pure copper wire, the other end of the wire isconnected to a pin.
(3) The C pillar is connected to the 40m pure copper wire supplied with the meter, and the other end of the wire is connected to pin 2.
2 ? Technical requirements for setting up the ground resistance tester
(1) The ground resistance tester should be placed 1-3m away from the test point, and the placement should be stable. .... ..>>
Question 3: How to use a megometer to measure whether the line is grounded If the electricity transmission and distribution line is grounded, you must use a megger. It is safe, compared to the earth resistance. If it is lower than the nominal value, it can be judged that there is a problem, and then it can be checked. Generally speaking, the nominal value is 1 MΩ/KV. For a 400 V line, use a 500 V megger. In theory it should be no less than 0.5, but generally it is no less than 1 MΩ to be considered.deem as qualified.
This multimeter is really not good. The voltage of this battery is too low and the judgment is inaccurate.
Question 4: How to use a megger to measure grounding? The megger must be an insulation resistance meter. It measures megohms, and the maximum grounding resistance is only a few ohms. so you cannot use a megger to measure grounding. There is another type called a grounding resistance meter, which is also hand-cranked. It requires two auxiliary ground rods. You must read the instructions.
Question 5: Operation steps of earth resistance test megger 1. The wiring of the terminal button of the meter must be correct 2. Adjust the mechanical zero position of the galvanometer after the meter is placed horizontally 3. "Set the magnification switch to ma magnificationximum. 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 dial matches the measured resistance value. 4. If the dial reading is less than 1 and balance has not been achieved, you can set the magnification switch to a smaller magnification until it is adjusted to complete balance. 5. If the galvanometer pointer of the instrument shakes, the crank speed can be changed to eliminate shaking. 6. If the sensitivity of the instrument galvanometer is too low, you can add water or salt water around the probe to moisten it.
Question 6: How to measure the resistance of the ground with a megometer A megometer cannot be used to measure the resistance of theground. To measure earth resistance, use an earth resistance measuring instrument. A megger, also called a megger, is used to measure insulation resistance. Usually, the insulation resistance of low-voltage electrical appliances cannot be less than 500,000 ohms. Therefore, the megohm meter's unit of measurement is the megohm, and one megohm is equal to 1,000,000 ohms. Earth resistance should generally be between 4 and 10 ohms, which cannot be measured with a megger.
Question 7: How to use the grounding meter? Using an oscillator
(1) Calibration of the counter. Before measurement, the megometer should be subjected to open circuit and short circuit test to check whether the megometer is in good condition. Open the two connecting wires, shake the handle, the pointer should point to "∞", then short circuit the two connecting wires, the pointer should panoint to "0", those that meet the above conditions are good, otherwise it cannot be used.
(2) the equipment under test is disconnected from the line and the large capacity equipment must be unloaded.
(3) Select a megger with a constant voltage level.
(4) When measuring insulation resistance, only terminals "l" and "e" are generally used, but when measuring insulation resistance of the cable at the earth or leakage current of the device under test is serious, it is necessary to use terminal "g", and connect terminal "g" to the shield or to the case. After the circuit is connected, you can turn the shake handle clockwise. Shaking speed should be slow to fast. When the rotation speed reaches about 120 revolutions per minute (zc-25 type), continue to rotate at a constant speed and read it. reading after 1 minute. Take action by shaking and don't stopz not to read.
(5) Disconnect and discharge. Once the reading is complete, shake slowly while removing the wires, then discharge the device under test. The discharge method involves removing the ground wire used in the measurement from the megometer and shorting it to the device under test (not to the megometer discharge).
Question 8: How to connect the oscillating meter to the insulation ground with one end connected to the conductor and one end connected to the shell. Shake the oscillating meter handle. If the pointer points to zero, it means it is grounded; if there is a reading, it means it is well insulated. In real applications it is often compared to the relevant driver. If it is smaller, that means it is grounded.