Insulation monitor principle and common failure analysis

Release time:


An insulation monitor is an instrument used to monitor the insulation status of electrical equipment, which judges the insulation status of electrical equipment by measuring insulation resistance. Its working principle is mainly based on the relationship between voltage and current, common insulation monitor using AC power supply, the test voltage applied to the electrical equipment under test, through the measurement of current to calculate the insulation resistance.
The working principle of the insulation monitor can be simply described as follows: when the electrical equipment is normally insulated, the test voltage is applied to the equipment, and only a small leakage current flows into the ground through the insulating material, at which time the insulation resistance is very large and the current is almost zero. And when the equipment insulation failure occurs, such as insulation material aging, damage, moisture and other reasons, the current will greatly increase, the insulation resistance decreases. Insulation monitor by measuring the change of current to determine the insulation status of the equipment, if the current exceeds a certain threshold, it is considered to be an insulation fault.
Common insulation monitor failure analysis includes the following aspects:
1. Measurement error: the insulation monitor may have a certain error in measurement, for example, due to the fluctuation of the measurement voltage source, the sensitivity of the current sensor and other reasons, resulting in a large deviation in the measurement results. In this case, you can calibrate the instrument or check whether the measurement voltage source and current sensor are working properly.
2. Power supply problem: insulation monitor needs stable AC power supply, if the power supply voltage is unstable or there is interference, it may affect the normal work of the instrument. In this case, you can check whether the power supply line is normally connected, whether there is stray current interference.
3. Sensor failure: the current sensor in the insulation monitor is the key component for measuring current, if the sensor is damaged or the sensitivity is reduced, it may lead to inaccurate measurement results. In this case, you need to check whether the sensor connection is good, whether there is damage and other issues.
4. Instrument failure: the insulation monitor itself may have faults, such as display damage, key failure, communication failure and other problems. In this case, consider replacing the display or keys, or check whether the instrument's communication module is working properly.
When using insulation monitors, they need to be inspected and maintained regularly to ensure that they work properly. At the same time, it is also necessary to pay attention to the operating specifications to avoid malfunctions caused by misoperation or other reasons. The insulation monitor can effectively monitor the insulation condition of electrical equipment, discover insulation faults in advance, and guarantee the safe operation of the equipment.