P-5000 Precision Current Transformer

APPLICATION

This transformer is very useful for high and low voltage work in the laboratory, shop, and field, for testing, measuring, and calibrating. The excellent accuracy and the One-to-One calibrating feature of the P-5000 transformer make it well suited as a standard for calibrating work. Because of the particular current ranges provided by this transformer (from 5 amperes to 5000 amperes), the P-5000 is especially well suited for testing current transformers for ratio errors and phase angle with the Knopp Transformer Comparator.

The range of a 5 ampere meter or wattmeter can be accurately extended by this transformer to cover all current values between 5 amperes and 5000 amperes, with the advantage that the ammeter need not be used below the half-scale point.

ACCURACY

The Knopp Precision Multirange Transformers have excellent ratio and phase angle performance, both inter-range and overall. The P-5000 transformer is furnished for a specified secondary burden, which can be any value between 0 and 25 volt-amperes. With a secondary burden of 15 volt-amperes, to give an example, the ratio of this transformer at 100% of full load current is well within .02% and the phase angle is within 1 minute, and at 10% of full load current the performance is within .04% and 2 minutes.

PRIMARY RANGES

A total of 30 primary ranges are provided. The self-contained primary ranges are: 5, 10, 15, 20, 25, 50, 75, and 100 amperes, and the following primary ranges can be obtained with an inserted primary of 1 primary turn: 5000, 4000, 3000, 2500, 2000, 1500, 1200; 2 turns: 1250, 1000, 750, 600; 3 turns: 500, 400; 4 turns: 625, 375, 300; 5 turns: 800, 240; 6 turns: 250, 200; 8 turns: 150; and 12 turns: 125 amperes. The secondary is 5 amperes.

INSULATION

The transformer housing insulates the inserted primary from the transformer windings for 2500 volt circuits. The wound primary is for use on 250 volt circuits.

CALIBRATION

The transformer can be calibrated in itself by the Knopp One-to-One method, by direct comparison of the primary current against the secondary current.

DESCRIPTION

The Type P-5000 Knopp Precision Multirange Transformer weighs 32.5 lbs.; and the bakelite case, which is fitted with a leather handle, measures 11.5" wide, 4.5" deep, and 13.875" high. The center opening is 4" in diameter. The secondary is provided with a convenient short-circuiting switch.