How to test the quality of cables with a megohmmeter

If it is a three-core cable, you separate the three ends at one end without contacting, and then use a megohmmeter at the other end to see if the three are short circuited to each other, if not, you short the three ends at one end, and measure the three at the other end to see if all three are connected. You can also connect one meter pen to the center of the cable, and the other meter pen to the cable insulation skin to see the degree of insulation.

When the digital megohmmeter measures the insulation resistance, the line L is connected with the conductive part of the object to be measured and insulated from the earth, and is grounded.

e Connect with the shell or grounding part of the object to be measured, shielding.

g is connected with the hidden part of the protection of the measured object or other parts that do not participate in the measurement, so as to eliminate the error caused by the leakage of the meter. When measuring the insulation resistance between components of an electrical product, it can be cleaned.

l and. e-terminations are made on either set of wire heads. For example, when measuring the interphase insulation of the generator, the three groups can be exchanged in turn, and the vacated one is safely grounded.

Here's how a megohmmeter can tell if it's good or bad:

1. Usually the megohmmeter is also called the shake meter, and the quality can be judged by shorting the meter;

2. When short-circuiting, a good megohmmeter can point to zero when the two wires are short-circuited;

3. When the two wiring are disconnected, the pointer points to infinity when the shaking speed reaches 120 revolutions per minute, and the needle can be pointed to any place when the shaking stops, and the good or bad can be judged after the above operations.

Megger, commonly known as shake meter, is mostly powered by hand-cranked generators, so it is also known as shake meter. Its scale is measured in megaohms (m). It is a kind of measuring instrument commonly used by electricians, mainly used to check the insulation resistance of electrical equipment, household appliances or electrical circuits to the ground and between phases, so as to ensure that these equipment, electrical appliances and circuits work in a normal state and avoid accidents such as electric shock and equipment damage.

Usually the megohmmeter is also called the shake meter, a good watch can point to zero by gently shaking the pointer when the two wires are shorted, and the pointer points to infinity when the shaking speed reaches 120 revolutions per minute when the two wires are disconnected. And when the shaking stops, the hand can be pointed anywhere.

Second-hand three-phase motor with megohmmeter, if the test is good or bad.

The measured value of cable insulation resistance stipulates that the insulation resistance should be measured before the power cable is put into operation, and the value of the 1kV shake meter should be used below 1kv, and its value should not be less than 10m.

Use the shake meter above 1kv: The insulation resistance value of the cable of 3kv and below is not less than 200m.

6 The insulation resistance value of 10kV cable is not less than 400m.

20 The insulation resistance value of the 35kV cable is not less than 600m.

The insulation resistance value of 220kV cable is not less than 4500m km.

Safety Technical Methods for Measuring Insulation Resistance of Cables:

1. First of all, remove the installed cable from other equipment at the connection after full discharge, wipe the cable joint clean, and keep a certain safety distance from the equipment.

2. Measuring shake meter: 1kV megohmmeter for cables of 1kV and below, and 2500V megohmmeter for cables above 1kV.

3. Before the insulation of the underground rocking cable with gas, it is necessary to check the low pressure of gas concentration within 10 meters around the roadway before telemetry.

Connect the instrument's power plug to the AC220V. Press the power switch to the ON position, preheat for 10 minutes, and the test can be normal.

Select the appropriate test voltage (500V).

Determine whether the "test" light is off, make sure that the binding post is not charged, connect the test piece, press the "test" button, and the instrument can charge the test piece and measure.

After the test is completed, press the "RESET" button or the test time is until the instrument automatically resets, and then the test specimen can be removed.

Repeat the above steps for the next measurement.

This tester can be used after the power is turned on, but in order to ensure accuracy, please warm up for more than 10 minutes.

When connecting the object to be measured, it must be in the reset state, that is, when the test light is off, to prevent high-voltage electric shock.

When measuring more than 100m, it is best to shield the measuring line. When wiring, the grounding post on the front panel of the instrument should be connected to the housing or housing of the DUT.

Try to avoid measuring too small a resistor, or shorting the two test clips. Earth Resistance Tester Instruction Manual (I=10a,

The instrument is equipped with a pair (two groups) of test wires, red thick wire to red current binding post, red thin wire to red resistance binding post, black thick wire to black current binding post, black thin wire to black resistance binding post. 2. Connect the power plug of the instrument to AC220V. Press the power switch to the ON position, and the digital tube of each window will turn on.

3. Turn the current adjustment knob counterclockwise to the zero position. 4. Before the test, select the range. 5. The clamps of the two sets of test wires are short-circuited to each other.

6. Manual test.

One megaohm is equivalent to 1,000,000 ohms. Why do we need to measure such a high resistance? Don't think about measuring resistance, think of it as test equipment.

It specifically tests the insulation of the motor windings. Depending on the insulation rating of the motor, a good motor can measure megaohms or 1,000,000,000,000 ohms well!

This is an insulation test of the windings of a motor, commonly known as a megohmmeter, megohmmeter or megohmmeter motor. We are testing the insulation of the motor, more specifically the insulation between the motor windings and the motor housing. If a small fraction of the current is flowing, it can be measured by these highly sensitive meters.

Motor insulation is rated and manufactured to withstand different temperatures. Time and heat can break the insulation of the motor. Proper use of a megohmmeter will test any motor insulation.

Depending on the level of insulation you are testing, this will have an impact on the number of ohms that the meter should read. To test high-grade insulation, you should use a megohmmeter that is capable of testing megohms. Otherwise, your test may be unreliable or inaccurate.

Most drives and drives are very sensitive to insulation losses, and the drive can preemptively shut down the motor to prevent drive damage. Ensure that the motor rating meets the environmental requirements and check the heat rating and use factor.

Respondent: Huatian Power.

The ME2670 digital megohmmeter consists of medium and large-scale integrated circuits. This digital megohmmeter has a large output power, a high short-circuit current value, and many output voltage levels (there are four voltage levels). The working principle is that the DC high voltage generated by the battery in the machine as the power supply through DC DC conversion is from the E pole to the L pole through the tested product, so as to generate a current from E to the L pole, and the insulation resistance value to be measured is directly displayed by the LCD after the I V transformation is completed by the divider.

ME2670 Digital Megohmmeter Features:

1. Large output power, strong load capacity, strong anti-interference ability.

The ME2670 digital megohmmeter is composed of high-strength aluminum alloy, equipped with an equipotential protection ring and a fourth-order active low-pass filter, which can effectively shield the external power frequency and strong electromagnetic field. For capacitive specimens, the output short-circuit current is greater than that, and it is easy for the test voltage to rise rapidly to the rated value of the output voltage. For low-resistance measurements, the voltage drop does not affect the test accuracy due to the proportional design.

2. The ME2670 digital megohmmeter does not require manpower to work, is powered by batteries, and the range can be automatically converted. The easy-to-use panel and LCD display make measurements easy and fast.

3. The output short-circuit current of ME2670 digital megohmmeter can be directly measured, and there is no need for on-load measurement for estimation.

Hello dear <>

The method of judging the good and bad of the three-phase five-wire cable with a megohmmeter is as follows; First of all, cut off the power supply of the three-phase low-voltage cable on the power supply side, hang the sign that it is strictly forbidden to close when someone is working, and arrange personnel to supervise on the spot to prevent someone from sending power. A 500-volt low-voltage megohmmeter was used to measure the insulation of the land-scattered cables that had been blacked out. The A phase and B phase of the three-phase cable are connected to the measuring line of the shake meter, and then the speed of 120 revolutions per minute is shaken, when the megohmmeter pointer shows that the Hui Xi stove is greater than or equal to the megohm, that is, it is qualified, and then the A and C phases, B phase and C phase are shaken in the same way, and the megohmmeter needle is qualified in the above and above.

I wish you a happy life! Hope mine is helpful to you ha.

Dear, good morning, I'm glad for your question, using a megohmmeter can test the insulation resistance of the cable, and then judge the quality of the cable. The specific operation steps are as follows: disconnect the three phase wires and two neutral lines of the three-phase five-wire cable from the old part of the whole excavation, so that it is completely isolated from the power grid.

Connect the positive and negative poles of the megohmmeter on any phase line and neutral line at one end, and select the appropriate test voltage and test range. The insulation resistance value of the cable is measured on the phase and neutral lines at the other end and recorded. Repeat the above steps to test the insulation resistance values of the other two phase and neutral wires, respectively.

The criterion for judging the quality of the cable is that the insulation resistance value of the cable should be greater than a certain threshold, and if it is lower than this threshold, it can be determined that the cable has an insulation fault. The magnitude of the threshold depends on the rated voltage level and length of the cable, and in general, the insulation resistance value should be greater than 1 megaohm. It should be noted that the test should ensure that the cable is completely isolated and that no voltage and current pass through, otherwise it will interfere with the test results.

At the same time, the appropriate test voltage and test range should be selected during the test to avoid damage to the cable. If you are not familiar with the operation or are unsure of the significance of the test results, it is recommended to seek professional help. I hope my answers can help you and I wish you a happy <>