Mains voltage stabiliser for battery charger - uses ferro-resonant transformer with load winding on outer limbs

摘要

Inherent voltage regulation to compensate for mains voltage variations is achieved by employing a ferro-resonant core type transformer between the supply and the charger. The primary (3) and resonant (4) winding are both on the central limb (1b) of the transformer core (1). Magnetic shunts (5) are placed between the windings. The output, or load, winding is divided into two coils (6), one on each outer limb (1c) of the core in a position in line with the resonance winding. Laminations (7) to increase the leakage flux are placed between output and resonance windings. The construction eliminates the need for a separate choke, specially tuned, in series with the output winding. To improve the output winding cooling an air gap (8) can be allowed between the external limbs of the coils (6) and the outer core limbs (1c).