Hammond 166U7 7.5V CT 15A Open Style Power Transformer, 112.5 VA

The 166U7 is a 112.5 VA low voltage power transformer delivering 7.5 V centre-tapped at 15 A from a 115 V, 60 Hz primary. It targets builders who need a heavy-current, low-voltage winding in an open style, chassis mount package, for example for filament or low-voltage DC supply circuits.

Construction follows the 166 Series design: an open style unit on a channel bracket, a dual bobbin winding arrangement that needs no electrostatic shield, and Class B insulation rated to 130 °C for extra protection, while the transformer is UL listed as a Class A (105 °C) design. Every unit is hi-pot tested at 2,000V RMS, and it is supplied with minimum 6 in long leads. The 7.5 V C.T. secondary provides two 3.75 V halves around the centre tap.

Overall dimensions are A 4.50 in (114 mm), B 2.50 in (64 mm) and C 3.00 in (76 mm). The 166U7 mounts with two holes of 0.203 in (5.2 mm) spaced 4.00 in (102 mm) hole to hole (mounting reference C). Shipping weight is 3.5 lbs (1.59 kg). On the drawing schematic the primary leads are black (BLK/BLK) and the secondary leads are green (GRN/GRN) with a green/yellow (GRN/YEL) centre tap.

The transformer is UL listed and CSA certified, and it is declared RoHS and REACH compliant. Check the 115 V, 60 Hz primary against your supply before ordering; for 117/234 V or 50/60 Hz operation across the range, or dual secondaries, the manufacturer points to its 266 Series.