Abstract: High voltage winding lead and terminal structures are disclosed. In the winding of slot wound transformers by means of a plurality of coils of fine wire, wherein each coil is of narrow width and large diameter, a severe problem of corona discharge is present in trying to make a connection to the inner end of each of the winding coils. To solve this problem, relatively wide members are provided on the coil form to form the winding slots. Grooves are provided in these members with a conductor of large cross section being placed in the groove to make an electrical connection with the inner end of each of the winding coils. Preferably, the large conductor is mounted tangent to the inner turn of the coil and the fine wire of the coil is pulled in contact with the conductor of large cross section by automatic winding machinery.

Abstract: A twelve pulse converter system is disclosed in which the two three-phase converter bridges forming the system are arranged one on top of the other in a single tower-like assembly and the valves of the bridges are disposed successively and separately as to phase. Additionally, the DC and AC terminals of one of the converter bridges are disposed on the one side of the tower-like assembly and the DC and AC terminals of the other of the converter bridges are disposed on the other side of the tower-like assembly, the DC terminals located on opposite sides being connected to each other by a DC lead.

Abstract: A high-voltage thyristor converter having a plurality of series-connected thyristor units and a gate control system. Each of the series-connected thyristor units has a plurality of series-connected thyristors and a gate-drive power supply circuit (hereinafter referred to as a gate power supply) connected between both extreme ends of the series-connected thyristors for supplying gate-drive power to the thyristors. The gate control system detects whether or not an output voltage of the gate power supply of at least one of the series-connected thyristor units is at least equal to or higher than a predetermined value and transmits a gate signal simultaneously to all of the thyristors when the output voltage is higher than the predetermined value, so that a protective action for preventing breakdown of the thyristors can be performed upon an instantaneous power failure or the like trouble.

Abstract: A high voltage transformer winding assembly is disclosed which enables tuning to preferably provide a rectangular pulse output for improving voltage regulation. The winding assembly comprises a pair of winding subassemblies mounted on opposite legs of a magnetic core. Each winding subassembly is provided with a plurality of windings. The plurality of windings of the two subassemblies are interconnected to form a plurality of winding pairs. The interconnection is such as to form an a-c null or minimal a-c voltage substantially at the connection point between the windings making up a winding pair. When the start turns of the windings are interconnected to form the winding pairs the a-c null of each winding pair appears adjacent the core to reduce the likelihood of corona discharge. The plurality of winding pairs are connected in d-c series aiding by means of diodes which provide a-c isolation between the winding pairs.

Abstract: Electrical ballast circuit for operating gaseous discharge lamps with direct current. An inductive reactor coil connected to an alternating current source is connected to a discharge lamp via a full-wave rectifier, and an auxiliary induction coil inductively coupled to the reactor coil is connected to the discharge lamp via another full-wave rectifier, resulting in the currents from the respective rectifiers to the lamp being out of phase with one another, thereby raising the average current through the lamp and the voltage across the lamp to prevent lamp de-ionization and reduce lamp re-ignition voltage. Series connected capacitors may be incorporated in the circuit to increase the starting voltage on the lamp if necessary.