Hammond 182M117 300VA Toroidal Transformer, Dual 117V Secondary

The 182M117 is a 300 VA low-voltage toroidal power transformer from the 182 Series, built for chassis mounting in equipment that runs from 117 VAC or 234 VAC mains at 50/60 Hz. Its dual secondary windings can be connected in parallel for 117V at 2.56A, or in series for 234V centre-tapped at 1.28A, making it a flexible choice for engineers designing linear power supplies and OEM equipment around a 117V or 234V C.T. rail.

The toroidal design keeps the unit low profile, lightweight and cool running thanks to its high efficiency. The dual primary is wired in parallel for 117 VAC or in series for 234 VAC, and the units are designed to have all windings engaged. Minimum 8 in long flexible leads simplify wiring, and each design is Hi-Pot tested at 4,000 V RMS between primary and secondary.

The transformer measures 5.06 in (129 mm) in outside diameter and 2.27 in (58 mm) high, and weighs 5.58 lb according to the series table (shipping weight 6.6 lbs (2.99 kg)). Mounting is by a single centre hole, and this unit has a potted centre for extra mounting strength. It is supplied with one bottom rubber insulating pad and mounting hardware, including a 1/4-20 bolt 2.50 in long.

The 182 Series is CSA certified to C22.2 #66 (file 209651), UL recognized to UL 506 (file E207860) and CE certified to IEC 950; this part is also listed as RoHS and REACH compliant. Because toroidal transformers can draw a high magnetizing inrush current for up to about half a cycle at switch-on, Hammond advises a slow-blow fuse, time-delayed circuit breaker or soft-start circuitry on the supply line.

Note: the 182 Series will soon be discontinued as a stocked series and has been replaced with the 1182 Series; this part is available while quantities last.