What is a MEG table and how to use it?

The MEG table is commonly known as shaking table. It is mainly used for measuring the equipment edge resistance, check whether the equipment or line leakage, insulation damage or short circuit.

Precautions for the use of the MEM table are as follows.

1. the correct selection of its voltage and measurement range.

2. When choosing Mega ohmmeter external conductors, a single copper conductor should be selected, and the insulation strength should be above 500V, so as not to affect the accuracy.

3.When measuring insulation resistance of electrical equipment, the power supply of the equipment must first be disconnected and measured without electricity. For longer cable lines, they should be measured after discharge.

4. MEG must be kept away from the strong magnetic field when it is used.

Before the measurement, an open circuit test and a short circuit test should be done first. The needle should be used in the open road test. It indicates that the working state of the MEG table is normal, and the electrical equipment can be measured.

When measuring, the surface of the tested electrical equipment should be cleaned to avoid causing large contact resistance and error in measurement results. It is important to note that when the capacitor is measured, the voltage of the capacitor must be greater than that of the mega meter. After the capacitance is measured, the shaking table must be removed first and then the shaking handle is stopped to prevent the charged capacitor from being damaged to the discharge of the shaking table. The capacitance to be measured will be discharged.

Megohmmeter for measuring electrical circuits and cables. When measuring Mega meter, we should pay attention to the L terminal connected to the end of the electrified body of the electrical equipment on the shaking table, and the terminals with E earthing should be connected to the enclosure or ground wire of the equipment.

When measuring the insulation resistance of the cable, the insulation resistance of the cable is measured in order to eliminate the reading error caused by the leakage of the surface in order to eliminate the reading error caused by the leakage of the surface, in addition to connecting the earth end of the MEG table to the electrical equipment and the other end of the line, and then connecting the inner insulating material between the core of the cable to the "protection ring" to eliminate the reading error caused by the leakage of the surface.

When the weather is humid, the protective ring should be used to eliminate the discharge of the insulation surface, so that the insulation resistance of the tested objects is lower than the actual value. After using Megohmmeter, the electrical equipment should also be discharged once. When using Megohmmeter, we must maintain a certain speed. According to the Megohmmeter, it is usually about 120r/min, and a stable reading is obtained after 1 min.

Do not touch the measured objects and mega ohmmeter terminals by hand to avoid electric shock. The swinging Mega meter handle should be slow and fast first. After the governor has slid, the speed must be kept stable. If the tested electrical equipment is short circuited, the needle should be stopped to shake the handle when it swings to 0, so as to avoid the Megohmmeter overheating and burning.

Note: when measuring the insulation resistance of electrical equipment with rated voltage of 500V, 1000~2500V Megohmmeter must be selected. When measuring electrical equipment with voltage below 500V, it is advisable to use 500V shake table.

This article is from Allicdata Electronics.