Hammond 166JB24 24V CT 1A Power Transformer, 24 VA

The 166JB24 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 24 V center-tapped (C.T.) secondary rated 1 A RMS, for a power rating of 24 VA. It suits OEM engineers, equipment builders and technicians who need a compact line-to-low-voltage transformer that bolts directly to a chassis.

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 and stripped 0.5 in, per the part drawing. The drawing identifies the leads as two 12V halves either side of a GRN/YEL center-tap lead.

Overall dimensions from the series table are A 3.25 in (83 mm), B 1.75 in (44 mm) and C 2.00 in (51 mm), with a D (hole-to-hole mounting) dimension of 2.81 in (71 mm); the mounting dimension column lists 0.19 in (5 mm) (mounting ref. C). The production drawing specifies A 3.250" ±0.063, B 1.750" ±0.125, C 1.995" ±0.063, D 2.813" ±0.063 and G 0.187" ±0.015. Shipping weight is 1 lbs (0.45 kg).

The 166JB24 drawing lists production test acceptance criteria: exciting current 56mA max. @ 115V, 60Hz, BLK - BLK; secondary no-load voltage 27.24V ±2% (GRN - GRN), with 13.62V ±2% (GRN - GRN/YEL = GRN/YEL - GRN); DC resistance 26.08 ±20% @ 20°C (BLK - BLK) and 1.518 ±20% @ 20°C (GRN - GRN); and a hi-pot test of 1500V, 60Hz, 1 sec (primary - secondary).

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.