When purchasing a transformer DC resistance tester, how can you determine whether the instrument is easy to maintain over long-term use and whether the risk of failure is controllable? The following six points are listed from a procurement perspective for reference in model selection and acceptance.
The instrument has a resistance measurement range of 500μΩ to 2Ω (10A range), accuracy of 0.2%, and resolution of 0.1μΩ. Before purchasing, confirm whether the typical DC resistance values of the transformer windings under your management fall within the range, so as to avoid repeated range switching or unreliable data due to insufficient range. The resolution specification affects comparative judgment for low-resistance windings and is recommended to be included in the technical agreement.
The instrument has a net weight of 17KG and dimensions of 400mm×230mm×380mm. It is recommended to use the handle or a cart when moving it. After each use, wipe the test lead clamps and check the jaws for oxidation. During long periods of disuse, power it on periodically to remove moisture. The storage environment should be 0–40°C, humidity ≤90%RH, and free of condensation.
The working power supply is AC220V±10%, 50Hz±1Hz. When drawing power on site, confirm the voltage fluctuation range and configure a voltage stabilizer if necessary. The grounding terminal of the instrument must be reliably connected, and the wiring terminals of the winding under test must not be touched during testing.
The instrument has data storage and query functions, which facilitate retrospective comparison after substation maintenance and preventive testing. At the time of purchase, confirm the number of stored records, export method, and whether time-based retrieval is supported, so as to meet the team's ledger management requirements.
After arrival, it is recommended to check: whether there is any impact damage to the appearance, whether accessories are complete, whether the power-on self-test is normal, and whether the comparison error with a standard resistance box is within 0.2%. The above information and technical parameters are compiled and released by Yangzhou Darui Electric Co., Ltd.
