Disclosed is a lamp transformer assembly, transformer winding arrangement and method of assembling a transformer assembly and lamp igniter transformer core. The lamp transformer assembly comprises a transformer core comprising two or more core members, wherein the core members ends are adapted to provide a transformer core with axially distributed air gaps. Furthermore, the transformer assembly comprises a primary and secondary winding, wherein one or more core members and the secondary winding are adapted to provide insertion of the one or more core members within the interior of the secondary winding. The transformer core members are attached to complete the core.