U.S. Philips Corporation

Leonard Woldring

Alexander Joseph Thiessens

Jozef C Moerkens

An electric device comprising at least one low-pressure mercury vapor discharge tube intended to be connected to an AC voltage source at a frequency of 50 to 60 Hz. The discharge tube is of a type which produces a comparatively large current distortion and has a proportionally low required reignition voltage. The electric device produces relatively small electric losses. The discharge tube remains operative even for small deviations of the nominal AC supply voltage.

Electric device comprising at least one low-pressure mercury vapor

The invention relates to a lamp unit provided with a mercury vapor discharge tube and a stabilization ballast which forms one mechanical whole therewith. This lamp unit is provided with a lamp base of a type which is customary for incandescent lamps. In accordance with the invention the discharge tube is a low-pressure discharge tube having a relatively high arc voltage. This results in a lamp unit whose ballast portion is small.

Discharge lamp unit including integral ballast

The invention relates to a method of manufacturing an inductive stabilizing ballast for a gas and/or vapor discharge lamp. According to the invention, after placing the laminations in and about the coil, part of each lamination is turned about an axis which is parallel to the center line of the electric coil so that the lamination parts are tightly turned against the electric coil. This leads to a satisfactory thermal contact between the coil and the casing so that the removal of heat from the coil is enhanced.

Inductive stabilizing ballast for a gas and/or vapor discharge lamp

The invention relates to a capacitively stabilized discharge lamp shunted by a coil. During the starting procedure of the lamp the coil is brought into saturation so that, by means of resonance with the capacitive ballast, a high voltage is applied across the lamp to start it. The B-H magnetization curve of the coil has been chosen so that a transition from the unsaturated condition to the saturated condition also occurs during the operating condition of the device, namely just before the lamp is extinguished during each half cycle of the a.c. supply voltage. Consequently the ratio of the r.m.s. voltage of the a.c. voltage source to the operating voltage of the lamp may be relatively small. A resistor having a positive temperature coefficient shunts the lamp and is in series with the coil so as to limit the electric current if the lamp refuses to start.

Electric device for starting and supplying a gas-and/or vapor discharge

The invention relates to a method of manufacturing an inductive stabilizing ballast for a gas and/or vapour discharge lamp. According to the invention, after placing the laminations in and about the coil, part of each lamination is turned about an axis which is parallel to the centre line of the electric coil so that the lamination parts are tightly turned against the electric coil. This leads to a satisfactory thermal contact between the coil and the casing so that the removal of heat from the coil is enhanced.

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Eindhoven, Netherlands

Leonard Woldring