Hammond 166M2 2.5V CT 3A Power Transformer, 7.5 VA

The 166M2 is a low voltage/filament power transformer from the 166 Series of economical single-primary, open style chassis mount transformers. It takes a 115V 60 Hz. primary and delivers a 2.5 V center-tapped (C.T.) secondary rated 3 A RMS, for a power rating of 7.5 VA. It suits OEM engineers, equipment builders and technicians who need a compact line-to-low-voltage transformer that bolts directly to a chassis. Rated 3 A (7.5 VA), it offers more secondary current than the 166K2 (1.5 A) and 166L2 (2.5 A) 2.5 V C.T. models.

Construction is open style with a channel bracket and two-hole chassis mounting. A dual bobbin design means no electrostatic shield is required, and the series uses Class B insulation (130 °C) for extra protection, while the design is UL listed as Class A (105 °C). Leads are a minimum of 6 in long. The drawing schematic shows black primary leads and green secondary leads, with a green/yellow center-tap lead.

Overall dimensions from the series table are A 2.81 in (71 mm), B 1.50 in (38 mm) and C 1.69 in (43 mm), with a D (hole-to-hole mounting) dimension of 2.38 in (60 mm); the mounting dimension column lists 0.19 in (5 mm) (mounting ref. C). The part drawing gives A 2.81 in / 71.4 mm, B 1.5 in / 38.1 mm, C 1.69 in / 42.9 mm, D 2.38 in / 60.5 mm and a width-wise mounting hole size of 0.187 in / 4.7 mm. Shipping weight is 0.7 lbs (0.32 kg).

The 166 Series is hi-pot tested at 2,000V RMS, UL listed and CSA certified, and this part is listed as RoHS and REACH compliant. For 117/234 V or 50/60 Hz operation or dual secondaries, the series literature points to the 266 Series instead.