Instruction Manual ct-t1
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- Điều hướng trang này:
- 5.3.1. Degauss
| 5.2.b) Equation:
tan σ = Δ y Δ x The combination of both Equations 5.2.a) and 5.2.b) leads to the conversion of the slope and the angle. 5.2.c) Equation: s = tan σ ⇔ σ = arctan s 5.3 Measurement Method The measurement method as described in ANSI/IEEE C57.13.1, IEC 60044-1 standards is implemented in the CT-T1. The CT-T1 applies an AC variable test voltage (up to 2000Vac) to the CT’s secondary windings. The test voltage and excitation current are applied to the CT under test during the excitation measurement process. Once tests are completed, the results can be saved internally or printed on the built-in printer. IEEE-30, IEEE-45, ANSI / IEC 60044-1 (10/50) knee point voltages are also calculated and printed on the test report. The CT-T1 determines the CT current-ratio using the ANSI / IEEE C57.12.90 measurement method. A test voltage is applied on the CT’s X terminals and the induced voltage is measured across the CT’s H1 and H2 terminals. The current-ratio is displayed on the screen and stored in memory. The current-ratio measuring range is from 0.9 to 15'000. Winding polarity is displayed as a plus sign (in-phase) or minus sign (out-of-phase). 5.3.1. Degauss To get rid of previously induced magnetization - also called remanence - the CT under test is demagnetized by saturating the core for a certain amount of time. The slope of the curve in the square log-log graph (see Section 5.1) is used to determine the state of the CT under test’s core. Figure 4 shows a simplified square log-log graph containing a generic knee point with an associated slope s Sat . The core is assumed to be sufficiently saturated when the slope is more flat compared to core’s linear region and generic knee point. The highest and therefore flattest knee point as defined in Section 5.4 is ASA 10/50: s ASA 10/50 ≈ 0.235. The saturation region is higher and the threshold for the saturation region is defined as: tải về 3.13 Mb. Chia sẻ với bạn bè của bạn:
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