Contaminants like moisture, dissolved acids and dirt can affect the resistivity of the insulation oil. Since these contaminants are conductive, they reduce the resistance of the insulation oil and may allow currents to flow. This may lead to short circuits and eventual failure of the electrical component. To help determine the effectiveness of the insulation oil, technicians test for the breakdown voltage. A small sample is taken and a high voltage is applied and slowly increased until electrical breakdown is achieved. A low breakdown voltage means the insulation oil needs to be replaced.
The Doble OTC is a test vessel that can hold a sample for insulation oil reliability. Aside from letting you test for breakdown voltage, it also allows you to test for dielectric constant and capacitance. This test vessel is used together with a power factor tester like the Doble M4100.
Protec offers the Doble Oil Test Cell and other test equipment for electrical maintenance. Rent, lease or purchase testers you need according to your needs. Contact us at 1-866-352-5550 for more details about our services.