Hammond 370EXP 119 VA 550V C.T. Potted Plate & Filament Transformer

The 370EXP is a 119 VA potted high voltage (plate) and filament power transformer from the 300P Series, built for designers and builders of equipment that need a plate supply and heater windings from one universal-primary transformer. At 119 VA it is the highest-rated model in the 3.31 x 3.88 x 4.25 in frame, with a 550V C.T. plate winding rated 144 mA, a 5V C.T. 3 A filament and a 6.3V C.T. 4 A filament. Its part drawing adds full lead colour coding and factory test limits.

The transformer is enclosed in a drawn steel case and completely potted in epoxy, finished in black powder paint to match the 1650P series of potted output transformers. Windings are concentric wound for low stray field and low noise, and a Faraday copper primary shield reduces capacitive coupling from the primary, attenuating higher frequency current coupling to the secondaries; the shield is internally grounded to the end bell.

The primary accepts 100, 110, 120, 200, 220, 230 or 240 VAC at 50/60 Hz. The 550V C.T. high voltage secondary is rated 144 mA and includes a 50 VAC bias tap (measured with the high voltage C.T. grounded), and the unit also provides a 5V C.T. @ 3A filament winding and a 6.3V C.T. @ 4A filament winding. It can be run full wave bridge or full wave C.T. The series is hipot tested at 2,000 VAC and is c UL us recognized (E207860), and the part drawing lists a primary-to-secondary hipot of 2500V, 60Hz for 1 second.

Listed dimensions are A 3.31 in (84 mm), B 3.88 in (99 mm) and C 4.25 in (108 mm). The 370EXP mounts using 1/4-20 threaded inserts, mounting hardware is included, and the shipping weight is 5 lbs (2.27 kg). All leads exit 8 in minimum and are stripped 0.5 in.