LB-634 - 

Features: The Low Boy™ power transformer is designed to surpass competitive market offerings in cost, size and versatility to the designer. Applicable to low clearance, stacked printed circuit board and solid state power designs, the Low-Boy will allow closer board stack spacing at lower power levels (down to 200 mA at 10 volts). Semi-toroidal construction reduces radiated magnetic fields and results in balanced windings. Non-concentric winding provides isolation by design, eliminating the need for an electrostatic shield. Allow 3⁄4" card spacing for 2 and 3, VA units; 1" for 4, 5, and 6 VA; 11⁄4" for 12 VA units. Dual primaries — 115/230 V, 50/60 Hz. Allows standard Hi-Pot — 2000 volts. Precision spaced PC terminals. UL Recognized unit (file card E-68100).
Explanation of Low Boy Interconnections. Because of the toroidal effect, two identical coils are connected in series or parallel, but one of the coils must be connected in reverse in order to get correct polarity and voltage.