How do I use the Megger?

How do I use the Megger?

Also known as megohmmeter, it is used to measure the insulation resistance and high value resistance of the device under test. It consists of a hand-cranked generator, header and three terminals (ie, L: line terminal, E: ground). End, G: shielding end).

Shake meter, also known as megohmmeter, its purpose is to test the insulation status of the line or electrical equipment. Use methods and precautions are as follows:

1. First, use a megger that is compatible with the voltage level of the device under test. For 500V and below lines or electrical equipment, use a 500V or 1000V megger. For lines or electrical equipment above 500V, use a 1000V or 2500V rocker.

2. When using a rocker to test the insulation of high-voltage equipment, it should be performed by two people.

3. Before the measurement, all the power of the tested circuit or electrical equipment must be disconnected. That is, the insulation resistance must not be measured. And to find out if no one on the line or electrical equipment can do it.

4. The table line used for the shaking table must be insulated wire, and it should not use double stranded insulated wire. The end of the table wire should be insulated; the “L” terminal of the rocking watch should be connected to the measured phase of the equipment. The grounding terminal "E" shall be connected to the untested phase of the equipment enclosure and equipment. The shielding terminal "G" shall be connected to the protection ring or the cable insulation sheath to reduce the measurement error caused by the leakage current of the insulation surface.

5, open before the measurement of the shake table open check. When the “L” side and “E” side of the shake table are shaken and shaken with no load, the pointer should point to “∞”; when the “L” side of the shake table is shorted with the “E” side, the pointer of the shake table should point to “0”. ". Description The rocker function is good and can be used.

6. The test line or electrical equipment must be grounded before testing. When testing the line, it must be done before the other party can allow it.

7. When measuring, shake the speed of the shake table handle to 120r/min evenly; after keeping the stable speed for 1min, take the reading so as to avoid the influence of the absorbed current.

8. Both hands must not touch two wires at the same time during the test.

9, the test should be completed before the stitches, shake the table after shaking. In order to prevent the electric equipment from being charged against the rocking table, the shake table is damaged.

10. When lightning, do not test the line insulation.

Problem sets:

A 380 volt motor typically uses a 500 volt or 1000 volt megohmmeter.

The oscillating meter measures the resistance by generating electricity by itself, and the object to be measured must not be charged. Before the test, it must be discharged first, otherwise it will affect the test result.

What is the insulation resistance standard for measuring the load with a shake meter?

The general measurement of more than 1MΩ meets the low-voltage equipment insulation requirements.

The current standard seems to be 380v 0.5M or more. According to the voltage, it can be explained by Ohm's law. That is, the voltage on the wire divided by the resistance of the insulating layer is equal to the current outside the wire. It can be guaranteed that there is no danger in touch. About 1000v=1M

How to Measure the Resistance of a Motor with a Shake Meter

I tell you how to judge whether the motor is good or bad. After disconnecting the connection, first, use a multimeter to measure the DC resistance of the three-phase winding. In fact, the resistance of the winding is very small. A very small motor, is to see if it can not pass two, if the three-phase windings are all connected, then use a line of the oscillating meter to connect the shell of the motor, and the other line to measure the resistance of the three-phase winding to the ground, The minimum value of the resistance must not be lower than 0.5 megohm 3. If the three-phase winding's resistance to earth is normal, the last is to measure the insulation resistance between the phases. You put a line of the megger to the terminal of the phase winding. The other one is connected to the other two terminals separately, and be careful not to connect two at the same time. After the test is finished separately, the process of measuring the phase between the other two phases of the winding to measure the phase between the other two phases only measures the upper or lower three wires. Column can be, the resistance must not be less than 0.5 megohms.

The two pens of the oscillating table are clamped on the terminal of the terminal box. One is clamped on the housing and shakes the handle of the oscillating table evenly. The reading obtained is the insulation resistance of the motor to the ground. Generally, it is qualified at about 200K to 2M. .

The two pens of the oscillating watch are respectively clamped on the terminals of the different phases of the terminal box, and the handle of the oscillating watch is evenly shaken. The obtained reading is the insulation resistance between the phases of the motor. Generally above 100K is qualified