The American Megger resistance tester MIT515 has arrived

The American Megger resistance tester MIT515 has arrived
Megger resistance tester is an instrument used to measure the conductivity of objects. Resistance testers are widely used in electrical safety inspections and grounding engineering completion inspections. There are many types of Megger resistance testers, including ground resistance testers, insulation resistance testers, ground resistance testers, DC resistance testers, surface resistance testers, and loop resistance testers

The American Megger resistance tester MIT515 has arrived
Megger grounding resistance tester refers to the resistance of buried grounding bodies and soil flow resistance, usually measured using a type of grounding resistance measuring instrument (or grounding resistance shaker). The shape of the type measuring instrument is similar to that of a regular insulation shaker, so it is commonly referred to as a grounding resistance shaker. The external structure of the shaking table may vary slightly depending on the model, but the usage method is basically the same. The grounding resistance measuring instrument comes with two grounding detection rods and three wires. The usage method and measurement steps are as follows:
(a) Grounding resistance tester (b) connecting wire (c) measuring grounding rod
1. Disconnect the connection point between the grounding main line and the grounding body, or disconnect the connection points of all grounding branches on the grounding main line.
2. Insert two grounding rods into the ground 400mm deep, one 40m away from the grounding body and the other 20m away from the grounding body.
3. Place the shaking table on a flat surface near the grounding body, and then connect the wires.
(1) Connect the terminal post E on the meter and the grounding body E 'of the grounding device with a connecting wire.
(2) Connect the terminal post C on the meter to the grounding rod C 'located 40m away from the grounding body using a connecting wire.
(3) Connect the terminal post P on the meter to the grounding rod P 'located 20m away from the grounding body using a connecting wire.
4. Adjust the coarse adjustment knob (with three adjustable ranges) according to the grounding resistance requirements of the tested grounding body.
5. Shake the shaker evenly at a speed of approximately 120 revolutions per minute. When the pointer deviates, adjust the fine adjustment dial immediately until the pointer is centered. The ground resistance of the tested grounding body is obtained by multiplying the reading obtained by adjusting the dial with the coarse adjustment multiple. For example, if the fine adjustment reading is 0.6 and the coarse adjustment resistor positioning multiple is 10, then the measured grounding resistance is 6 Ω.
6. To ensure the reliability of the measured grounding resistance value, the orientation should be changed and retested. Take the average of several measurements as the grounding resistance of the grounding body.

Usage of Megger Resistance Tester
Before measurement, the power supply of the tested equipment must be cut off and short circuited to ground for discharge. Under no circumstances should the equipment be charged for measurement to ensure personal and equipment safety. For equipment that may induce high voltage electricity, this possibility must be eliminated before measurement can be carried out.
2. The surface of the tested object should be cleaned to reduce contact resistance and ensure the accuracy of the measurement results.
Before measurement, the megohmmeter should undergo an open circuit and short circuit test to check if it is in good condition. Before the megohmmeter is connected to the measured object, shake the handle to reach the rated speed of the generator (120r/min) and observe whether the pointer points to the "∞" position on the scale. Short circuit the terminal "wire (L) and ground (E)", slowly shake the handle, and observe whether the pointer points to the "0" position of the ruler. If the pointer cannot reach the designated position, it indicates a malfunction in the megohmmeter. It should be repaired before use.
When using a megohmmeter, it should be placed in a stable and secure place, and kept away from large external current conductors and magnetic fields.
5. Wiring must be done correctly. A megohmmeter usually has three terminals, with L connected to the insulated conductor part between the tested object and the ground, and E connected to the shell or ground of the tested object. G is connected to the shielding of the tested object or the part that does not require measurement. When measuring insulation resistance, generally only the "L" and "E" terminals are used. However, when measuring the insulation resistance of cables to ground or when the leakage current of the tested equipment is severe, the "G" terminal should be used and connected to the shielding layer or shell. After the circuit is connected, the handle can be rotated clockwise. The shaking speed should be slow and fast. When the speed reaches about 120 revolutions per minute (ZC-25 type), maintain a constant speed and read after 1 minute. The reading should be taken while shaking and should not be stopped.
During shake testing, place the megohmmeter in a horizontal position and ensure that there is no short circuit between its terminals when the handle rotates. The shaking of the handle should gradually increase from slow to fast. If the pointer points to zero, it indicates that the tested insulation material may have a short circuit. At this time, the handle cannot be further shaken to prevent damage to the coil inside the meter due to heating.
7. The reading is complete. Discharge the tested equipment. The discharge method is to remove the ground wire used for measurement from the megohmmeter and short-circuit it with the tested equipment (not discharge from the megohmmeter).

Megger Resistance Tester Product Application:
·Equipment design for insulation testing of high-voltage electrical equipment
·Wide voltage range also allows testing of low-voltage equipment
·Generators, motors, transformers, cables, and switches all require effective maintenance
·Insulation resistance of high-voltage power cables and high-voltage buses
·Insulation resistance of large motor/generator windings
·Insulation resistance of line and substation transformers