Hammond CT150A 150:5 Toroidal Current Transformer, 1.2% Accuracy

The CT150A is a 150:5 toroidal current transformer with 1.2% rated accuracy at a 2 VA burden. It shares the compact 3.75 in frame of the smaller models while offering tighter accuracy, making it useful for monitoring feeders around 150 A on a standard 5 A ammeter.

The unit is a toroidal current transformer fitted with a two hole mounting bracket and 24" insulated secondary leads with crimped ring connectors. A bare primary conductor may be used in circuits up to 600 V (4 KV Hi pot); at higher voltages, use a suitably insulated conductor. The series carries UL E227616 volume #1, file number X0DW2.

Overall dimensions for the CT150A are A 3.75 in (95 mm), B 1.35 in (34 mm), C 3.25 in (83 mm), D 3.00 in (76 mm), E 1.20 in (30 mm) and F 2.87 in (73 mm), with mounting slots G 0.22 in (6 mm) by H 0.37 in (9 mm). The listed shipping weight is 1.05 lbs (0.48 kg); the series table gives 1.4 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. Because the ratio can be reduced by looping the conductor, a CT150A can also serve a 75:5 application with 2 primary turns through the window, following the series method of choosing a primary that is a multiple of the required rating.