Hammond CT500A 500:5 Toroidal Current Transformer, 2-20 VA Burden

The CT500A is a 500:5 toroidal current transformer with 0.3 - 1.2% rated accuracy and a 2 - 20 VA burden range. It is the largest ratio on the 4.75 in frame and the first with accuracy down to 0.3%, suited to metering 500 A feeders on a 5 A ammeter.

Construction is a toroidal design with 24" insulated secondary leads terminated in crimped ring connectors, and every model in the series has a two hole mounting bracket. It is suitable for use with a bare (uninsulated) primary conductor in circuits up to 600 V (4 KV Hi pot), or at higher voltages when a suitably insulated conductor is used. The series is listed under UL E227616 volume #1, file number X0DW2.

Overall dimensions for the CT500A are A 4.75 in (121 mm), B 1.35 in (34 mm), C 4.25 in (108 mm), D 4.00 in (102 mm), E 2.20 in (56 mm) and F 3.87 in (98 mm), with mounting slots G 0.22 in (6 mm) by H 0.37 in (9 mm). The listed shipping weight is 1.69 lbs (0.77 kg); the series table gives 1.8 lb. It is RoHS and REACH compliant.

To measure current, pass the wire carrying the current through the CT window so it acts as the primary winding, then connect the secondary to an ammeter with a 5 A movement. Where higher burden is needed at a lower current, the conductor can be looped through the window; the number of turns equals the multiple between 500 A and the required primary rating.