Motorola Lighting, Inc.

Motorola Corporation

Rembert R Stokes

Youngkee Ahn

Anand K Upadhyay

Fred E Ostrem

David J Priniski

A transformer (202) has a bobbin (2) which has an inner portion (104) supporting an inner electrical winding (140) and having a magnetic core recess. The inner portion is located within an outer portion (4) supporting an outer electrical winding (40). The inner portion further has an end with a termination connected to the inner winding, an annular recess (126) in which the inner winding is situated, and a channel (132) communicating between the termination end of the inner portion and a remote end of the annular recess. The channel is positioned radially inwardly of the first annular recess and accommodates a portion of the inner winding. By providing the channel radially inwardly of the annular recess, winding wire can extend between the termination end of the inner portion and the remote end of the annular recess across the annular recess without significantly increasing the size of the inner portion and without increasing the gap between the inner and outer portions. This allows the size, weight and cost of a transformer built with the bobbin to be reduced, and improves the transformer's magnetic performance. The channel also allows layered windings terminating at the same end of the inner portion to be formed from an odd number of winding passes, reducing corona voltage breakdown effect and so prolonging the practical life of the windings. This also allows the inner portion to be wound uninterruptedly by machine without manual intervention.

Bobbin for electrical windings

A transformer or inductor bobbin (2) having pins (24) of a rectangular cross-section with complementarily profiled ends (24A, 24B), of which one (24A) is tapered and the other (24B) has a recess (24E). The rectangular cross-section allows the pins to offer greater resistance to bending in the direction of their cross-section's greater dimension (for pulling winding wire from the pins), while offering easier bending in the direction of their cross-section's greater dimension (for clinching to a printed circuit board). The use of pins having complementary profiles at their opposite ends allows the pins to be separated simply and efficiently from a length of material with no material wastage, and the provision of a taper at one end of a pin and a recess at the other end allows easy insertion of the tapered end into a pre-formed printed circuit board hole while the recessed end provides for collection of scraped material during pin insertion into an undersized hole (22) in the bobbin. The undersized hole (22) is open at its top, allowing 'out-gassing' of otherwise trapped air during soldering.

Bobbin for an electrical winding and method of manufacture

A transformer bobbin (2) having pins (24) extending therefrom is fabricated by winding connecting wire around the pins and pulling the wire until it breaks, then soldering the wire to the pins. The stresses imparted to the pins cause the pins to become mis-aligned when the bobbin material becomes softened during soldering. In order to correct this misalignment the pins are inserted, while the bobbin material is still soft, into holes (36) in a plate (34). The holes are aligned in the desired alignments of the pins and have at their upper ends (38) tapering profiles which contain the mis-aligned pins and guide them into their desired alignments. The pins are retained in the plate until the bobbin material has resolidified and the pins have become fixed in their desired alignments. During this time electrical continuity testing is performed on the soldered transformer.

Method of fabricating an electrical component assembly

Gas discharge lamp ballast

An electrical component/housing has a main body with a geometric central point and a lead frame having a plurality of leads formed of flat sheet stock. An intermediate flexible planar portion of each lead extends between emerging and end portions of each lead. The intermediate portion is orientated toward the central point so as to maximize absorption of thermal expansion stresses which are radially directed between the central point and the end lead portion which will be bonded to another structure. Also, a thermally stable connection arrangement comprising: a substrate having an electrical conductor thereon to which a component lead is connected at a third position, the substrate having a first coefficient of thermal expansion (a.sub.1); a heat sink base upon which the substrate is located at a first position, the base having a second predetermined coefficient of thermal expansion (a.sub.2); and a housing fixed to the base at a second position and having the lead extending therefrom to the electrical conductor to which it is soldered, the lead having a third predetermined coefficient of thermal expansion (a.sub.3). A first distance (l.sub.1) between the first position and the third position and a second distance (l.sub.2) between the first position and the second position being in the ratio (a.sub.2 -a.sub.3)/(a.sub.1 -a.sub.3) so that there is substantially no differential movement due to thermal expansion between the substrate and the component lead at the third position.

Electrical device having improved lead frame and thermally stable

A signal wrap for transducer fault isolation for use in a telephone system providing remote isolation and identification of malfunctions in end-user telephone equipment such as a handset microphone and handset receiver (earpiece speaker) with an associated sound source and sound receiver.

Growing community of inventors

Inverness, IL, United States of America

Rembert R Stokes