The Usage Methods of Megohmmeters

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The megohmmeter, also known as the insulation resistance tester, is mainly used to measure the insulation resistance of electrical equipment. The following are its usage methods:

### Preparation Work
1. **Select the appropriate megohmmeter**: Select a megohmmeter with a corresponding voltage level according to the voltage level of the equipment to be tested. Generally speaking, for equipment with a voltage of less than 500V, a 500V or 1000V megohmmeter can be selected; for equipment with a voltage of more than 500V, a 1000V or 2500V megohmmeter should be selected.
2. **Check whether the megohmmeter is in good condition**: Before use, place the megohmmeter horizontally first. Shake the handle of the megohmmeter without any load to make the generator reach the rated speed. At this time, the pointer should point to "∞". Then, short-circuit the two terminals L (line) and E (ground). Shake the handle slowly, and the pointer should point to "0". If the pointer cannot point to the corresponding position, it indicates that the megohmmeter is faulty and needs to be repaired or replaced.
3. **Cut off the power supply of the equipment to be tested**: And fully discharge the equipment to ensure the safety of personnel and equipment. The discharging method is to short-circuit the terminals of the equipment to the ground, and the discharging time is generally not less than 2 minutes.
4. **Clean the surface of the equipment to be tested**: Use a clean cloth or brush to remove dust, oil stains, moisture, etc. on the surface of the equipment to be tested, so as not to affect the measurement results.

### Wiring
- **General measurement**: Connect the L terminal of the megohmmeter to the conductive part of the equipment to be tested, and connect the E terminal to the casing or grounding part of the equipment to be tested. If measuring the insulation resistance of a cable, the G (shield) terminal of the megohmmeter should also be connected to the shielding layer of the cable to eliminate the influence of the leakage current on the cable surface on the measurement results.
- **Special cases**: For a double-winding transformer, when measuring the insulation resistance of the high-voltage winding to the low-voltage winding and the ground, connect L to the high-voltage winding and E to the low-voltage winding and the casing; when measuring the insulation resistance of the low-voltage winding to the high-voltage winding and the ground, connect L to the low-voltage winding and E to the high-voltage winding and the casing.

### Measurement
1. **Shake the handle**: Shake the handle clockwise at a uniform speed to make the generator speed gradually reach the rated speed (generally 120r/min). During the process of shaking the handle, keep the speed stable and avoid shaking it too fast or too slow, so as not to affect the accuracy of the measurement results.
2. **Read the value**: After the pointer stabilizes, read the value indicated by the pointer, which is the insulation resistance value of the equipment to be tested. When reading the value, it should be carried out at specific times such as 15 seconds and 60 seconds after the pointer of the megohmmeter stabilizes, so as to facilitate the comparison and analysis of the measurement results. For the measurement of the absorption ratio, the insulation resistance values at 15 seconds and 60 seconds should also be read respectively, and the absorption ratio (R60/R15) should be calculated.
3. **Measurement time**: For large-capacity equipment, such as large transformers, generators, etc., the time for measuring the insulation resistance should be appropriately extended, generally not less than 1 minute, to ensure the accuracy of the measurement results.

### Wrapping-up Work
1. **Stop shaking the handle**: After the measurement is completed, stop shaking the handle first, and then remove the connection wires on the L and E terminals to avoid damaging the megohmmeter due to the reverse charging of the equipment to be tested to the megohmmeter during the disconnection process.
2. **Discharge the equipment to be tested again**: After the measurement, since the equipment to be tested may have been charged during the measurement process, it needs to be discharged again to ensure safety.
3. **Arrange the equipment**: Wipe the megohmmeter clean and store it properly for future use. At the same time, record the measurement results well for analysis and comparison.

When using the megohmmeter, it is necessary to strictly abide by the operating procedures to ensure the safety of personnel and equipment. When using the megohmmeter in a humid environment or at high altitudes, corresponding safety measures should also be taken.#tiktokrefugee#cat#tiktokban#china#抖音难民#transformers #transformer #electrical #technology #factory #foryou #viral #shortvideo #manufacture #machine #power #shorts #trending #wiring #factorywork #electricalengineering #powertransformer #electriacaltransformer #manufacturing #process #manufacturer #manufacturingprocess #HighVoltageWinding #usa #canada #australia #uk#dailyvlog #daily #bluecollar #Tesla#WorkshopDaily #electricwire #powerengineering #transformer #foilwinding #lowvoltagenation #electricalengineering #LowVoltageFoilWinding #FoilWinding #ElectricalEngineering #TransformerDesign #InductorDesign#TransformerTechnology #ElectricalEngineering #FoilWinding #TransformerManufacturing #EnergyEfficiency #ElectricalDesign #TransformerWinding #EngineeringInnovation #TransformerTechnology #CopperFoilWinding #PowerTransformers #EngineeringTechniques #ElectricalComponents