The polarity markings on a CT designate the general immediate directions of the currents. The polarity examination shows the predicted course of supplementary CT recent (leaving) is actually appropriate for certain direction of major latest (penetrating).
Taking care to see right polarity is essential whenever installing and linking present transformer to power metering and safety relays. In one immediate of the time, your major existing is going into the biggest terminal the corresponding secondary present should be making the likewise noted second terminal.
A CT under test was assumed to own appropriate polarity if instant present path for primary and second present is actually contrary to each other. CT Polarity is crucial when CT’s are now being put along in single-phase or three-phase programs.
Most contemporary time CT examination machines is capable of carrying out the proportion examination automatically using a simplified examination lead setup and can exhibit polarity as proper or incorrect. CT polarity try verified manually by utilizing a 9V electric battery and analogue voltmeter making use of soon after test procedure:
Marks on latest transformers have been from time to time misapplied from the manufacturer. You’ll be able to confirm the polarity of a CT in that particular niche with a 9V electric battery. Photograph: TestGuy.
CT Polarity Test Therapy
- Detach all-power just before evaluating and hook the analog voltmeter towards the secondary terminal from the CT are tested. The positive terminal with the meter are attached to terminal X1 for the CT as the negative terminal is actually connected to X2.
- Manage an item of line through the large side of the CT screen and fleetingly make contact with the good end of the 9-volt power into the H1 side (sometimes marked with a mark) therefore the unfavorable end to your H2 part. Читать далее A CT under test was presumed to own correct polarity if immediate latest direction for major and additional current try reverse to each other. Photo: TestGuy.