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Spot Bad Insulation with Doble Test Sets

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Doble insulation testers are extensively used in insulation testing of transformers and motors. Because of the popularity of the test equipment used in this test, this procedure is eventually called Doble test. Doble Engineering is one of the leading manufacturers of high quality electrical diagnostic equipment. Many trust this brand because of its durability and accurate measurements.


The purpose of an insulation resistance test is to detect the presence of moisture or contamination which can cause tracking and eventually short circuit. This can be dangerous because it can cause electrical fires or shock to personnel. A Doble test is performed by passing a high voltage alternating current to the insulation wall of the test device. With this setup, it forms a capacitor and allows a small capacitive current to pass through the insulator. Any sudden increase of this current during the test can be an indicator of insulation problems like moisture or conductive contaminants. This can cause arcing and char the remaining insulation which can cause catastrophic damages to equipment. Regular tests will prevent such events from happening.

Doble insulation testers and other diagnostic equipment are available for rent through Protecequipment resources. We also offer other high voltage test equipment from leading manufacturers. Contact us now for test equipment rental rates.