High-voltage insulation resistance tester (also called megohmmeter) is widely used to test the insulation performance of electrical equipment such as cables, transformers, motors, and generators. After getting the meter, many users first face the two most practical questions: "Which voltage range should I choose to measure?" and "Is the measured value qualified?"
Select the wrong voltage - the measured results may be falsely high or falsely low, or even damage the device under test.
This article takes the EM3500 series high-voltage insulation resistance tester as an example to sort out the test voltage ranges applicable to different equipment and the reference values for the qualification of insulation resistance.
Test voltage range applicable to the same equipment
The EM3500 series provides multiple voltage levels (ETCR3500: 50V ~ 5kV, a total of 6 levels; EM3500B: 50V ~ 10kV, a total of 7 levels). The following is the most commonly used voltage selection reference:
Type of Tested Equipment | Recommended Voltage Gear | Description |
Low-voltage electrical circuits (380V and below) | 500V | Commonly used for household and commercial low-voltage circuits |
10kV power cables | 2.5kV or 5kV | 5kV is recommended for long cables for faster charging |
Transformers of 35kV and above | 5kV or 10kV (3500B only) | High voltage is required for windings on the high-voltage side |
6kV/10kV high-voltage motors | 2.5kV or 5kV | Select according to the rated voltage of the motor |
Arresters and insulators | 5kV | With high withstand voltage, sufficient test voltage is required |
Insulation material samples | Subject to material standards | Generally ranging from 500V to 5kV |
See the picture below. The gears on the instrument knob correspond to different test scenarios. Turn to "V" to measure AC/DC voltage (used to check whether the device under test is charged);
Figure 1. Gears Rotary Knob Diagram
Guangdong Yidian Measurement and Control Technology Co., Ltd. specializes in the research, development, and production of power testing instruments and power quality management solutions. With nearly two decades of deep involvement in the power industry, the company remains committed to technological innovation and independent R&D, meticulously crafting every product and providing attentive service to every customer. The company actively supports OEM and ODM customization services, tailoring solutions to meet specific customer needs and creating greater value for them. Yidian Measurement & Control is the manufacturer of the EM3500, EM3520, 5 kV high-voltage insulation resistance testers, EM3500B, EM3520B, 10 kV high-voltage insulation resistance testers, EM3520C, 15 kV high-voltage insulation resistance testers, and the EM3580 online insulation resistance tester.
ETCRMETER is a high-end brand of ETCR. All products are manufactured by ETCR, which also provides technical support and after-sales service.
For more information, please visit the Yidian Measurement & Control official website: www.etcrmeter.com
10th Floor, Block 5, Liandong Intelligent Manufacture Park, No. 105, Shilong North Road, Nanhai District, Foshan City, Guangdong, China
