FLUKE 505 Transformer Analyzer

The MODEL 505 Transformer Analyzer is designed for testing current transformers ( CT) and potential transformers ( PT) without interruption of the customer’ s service. This instrument measures CT admittance, CT ratio, CT primary-to-secondary phase angle and the voltage, current and phase angle of the service. With the ‘ Burden CT/ PT Option’ , it determines the CT secondary burden capability, the regulation of the PT and its secondary burden capability and provides for CT core demagnetization.

The CT Admittance Test feature provides the capability of testing a CT with or without secondary current flow. It displays the admittance value of the CT loop which can be recorded and used as a reference value on future tests. Shorted turns, circuit shunts, minor deterioration in CT performance, defective watthour meter current coils, defective test switches, and high resistance connections are easily detected from the admittance value.

The CT Ratio Test feature provides for measuring the CT ratio as an ‘ Actual’ ratio or a ‘ Best Fit’ ratio. If the CT/ PT Burden option is installed, ratios can be measured with and without burden applied. In addition, the phase angle between the primary and secondary is measured.

CT or PT Burden Tests can be performed using two methods. The first method allows the user to add an individual burden to the secondary. The second method allows the user to add a complete sequence of burdens to the secondary. The on-board microcontroller automatically applies the burden for 1 second to prevent resistive element burnout. The display provides for the recall of test values for each burden applied. The Before Burden, and After Burden currents are displayed together with the Percent ( % ) of change between Before and After Burden readings.

The measurement technique of the 505 eliminates the uncertainty of burden testing in services where continuous current changes are present. It reduces the interpretative requirements of the user since the reduction of CT secondary loop current due to the addition of the selected burden is displayed as a % of the original current. This new measurement method can respond to CT secondary loop currents as low as 0.2 amperes. When performing PT burden testing, both of the test methods can be performed with and without the meter voltage coil attached to the PT secondary.

A CT Demagnetization, or demag, can be done easily if the CT has at least 2.5 amperes in the secondary loop. A quick demag test on a CT that is saturated can save time and money by preventing the uneccesary change out of a good CT. This function applies a series of resistances in a smooth fashion from 0.1 ohm to 8 ohms and back down to 0.1 ohm again to the CT secondary loop. This over burden applied should drive the CT over the knee of the Bh curve ( saturating the CT) and demagnetize the core.

Data collected during the test may be saved. Test records can be stored and downloaded to software provided for viewing and exporting the saved test results. Saved data may also be recalled for viewing from the 505.

The Model 505 Transformer Analyzer is the ultimate answer to in service CT and PT Testing!