This article mainly explains the measurement cases and methods of insulation resistance.
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Note: The insulation resistance test can only be carried out on the circuit without electricity. Before the test, check whether the test wire is good and confirm whether the circuit under test is powered.
One or four steps insulation resistance test method
Step 1: Turn the rotary switch to Ω, then press the yellow VSEL button on the left to select the voltage to be tested. There are: 250V/1000V/2500V/5000V
Step 2: Connect the grounding wire (black) to the EARTH end of the ES3025E meter and the other end to the ground of the device under test.
Step 3: One end of the high voltage bar test line (red) is connected to the LINE end of the ES3025E meter, and the other end is in contact with the device under test.
Step 4: As shown below, press the red TEST test button. The LCD displays the measured value. After the measurement, the display value is fixed and the insulation resistance value is read.
Second, insulation resistance meter measurement application
Measuring cable insulation resistance
Measuring the insulation resistance of the generator
Measuring motor insulation resistance
Third, the insulation resistance size index
1. The insulation resistance of low-voltage lines and equipment after new and overhaul should not be less than 0.5 megaohms.
2. The value of the insulation resistance of the low-voltage line and equipment and 毎V voltage in operation shall not be less than 1 kΩ, for example 220V, the insulation resistance value shall not be less than 0.22 mega ohm, and the 380V shall not be less than 0.38 mega ohm.
3. The insulation resistance of the line and equipment in the humid environment and the electric volts per volt is not less than 500 ohms.
4. The insulation risk of portable electrical equipment or hand-held power tools should not be less than 2 megohms.
5. The insulation resistance of the control circuit should not be less than 1 megohm. In humid environments, it can be reduced to 0.5 megohms.
6. Overhead lines The insulation resistance of each suspension insulator should not be as low as 300 megohms.
7. The insulation resistance of high-voltage lines and equipment is generally not less than 1000 megohms.
The insulation resistance of the 8, 6 to 10 kV cable line is not less than 400 to 1000 megohms.
9. The insulation resistance value before the power transformer is put into operation should not be lower than 70% at the time of shipment, and it can be appropriately reduced during operation.
When the rated load of the motor is working to a steady state, the insulation resistance Rm (in MΩ) between the winding and the casing shall conform to the relationship expressed by the following formula. Rated voltage / V ≤36 >36--500 >500--3300 >3300 Use the specification of the megohmmeter /V 250 500 1000 2500
Where: U is the rated voltage of the motor winding of the test, the unit is V; P is the rated power of the tested motor, the unit is kw. Rm≥U/(1000+P/100) Convert cold resistance value for reference: RMC≥U÷1000×(75-t)÷5 Where: RMC----Cold resistance evaluation value (Mega) t----the temperature of the winding during measurement (°C) u----the rated voltage of the winding (V).
Fourth, insulation resistance meter product introduction list Product model: ES3025 Product name: Digital insulation resistance meter Features: Function: insulation resistance test, voltage test, rated voltage (V): 100; 250; 500; 1000; 2500, insulation resistance range (GΩ): 0.01MΩ ~ 200GΩ , DC voltage range: 0 ~ 1000V, AC voltage range: 0 ~ 750V, data storage: 500 groups......[detailed]
Product model: ES3025E Product name: Digital high-voltage insulation resistance meter Features: Function: insulation resistance test, voltage test, rated voltage (V): 250; 500; 1000; 2500; 5000, insulation resistance range (GΩ): 0.01MΩ ~200GΩ, DC voltage range: 0 ~ 1000V, AC voltage range: 0 ~ 750V, data storage: 500 groups......[detailed]
If you need to buy an insulation resistance tester or consult more about insulation resistance measurement. QQ or dial http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
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